Jostein Grytten

• Islam, Md Monirul; Põld, Ave; Janssen, Jip; Németh, Orsolya; Listl, Stefan & Grytten, Jostein Ivar [Vis alle 8 forfattere av denne artikkelen] (2026). Factors Influencing the Inter-Country Movement Intentions of Future Dentists in Ireland: A Cross-Sectional Study. International Journal of Dentistry. ISSN 1687-8728. 2026(1). doi: 10.1155/ijod/6636193. Fulltekst i vitenarkiv
• Linde, Astrid de; Grytten, Jostein Ivar; Skau, Irene & Kinge, Jonas Minet (2025). Maternity Ward Closures and Infant Health Outcomes, Maternal Health Outcomes, and Birth Procedures. Health Economics. ISSN 1057-9230. 35(2), s. 360–376. doi: 10.1002/hec.70053. Fulltekst i vitenarkiv
• Jiang, Nan; Kinge, Jonas Minet; Skau, Irene & Grytten, Jostein Ivar (2025). COVID-19 and access to subsidized dental care according to household income. A register-based population study from Norway. Acta Odontologica Scandinavica. ISSN 0001-6357. 84, s. 600–606. doi: 10.2340/aos.v84.44938. Fulltekst i vitenarkiv Vis sammendrag

  Objective: The objective of this study was to examine inequalities in access to subsidized dental care according to household income before, during and after the COVID-19 lockdown in Norway. Material and methods: Our data encompassed all individuals aged 20 years and above (n = 3,977,747). The data were analyzed using a linear probability model. The outcome variable was whether an individual had received subsidized dental care, and the main independent variable was net household income. Analyses were carried out with and without the following control variables: gender, age (fixed effects), level of education, immigrant background and place of residence (fixed effects for county). Inequalities were measured using concentration indices. Results: The proportion of adults who received subsidized dental care was 3.10% before lockdown, 0.47% during lockdown and 2.15% after lockdown. The concentration indices were small. The unstandardized concentration indices (without control variables included) were: 0.04 before, 0.002 during and 0.04 after lockdown. The standardized concentration indices (with control variables included) were: 0.02 before, −0.007 during and 0.02 after lockdown. We carried out several supplementary analyses. They all supported our main findings. Conclusion: The lockdown did not lead to inequalities in access to subsidized dental care in Norway according to income.

• Grytten, Jostein Ivar & Skau, Irene (2025). Mothers’ level of education and infant health. Causal effects of the introduction of a school reform in Norway. Social Science and Medicine. ISSN 0277-9536. 386. doi: 10.1016/j.socscimed.2025.118632. Fulltekst i vitenarkiv
• Fardal, Øystein & Grytten, Jostein Ivar (2025). A retrospective study of stabilizing bridges in patients with stages III and IV periodontitis - o to 35 years of clinical audit. Journal of Clinical Periodontology. ISSN 0303-6979. doi: 10.1111/jcpe.14116. Fulltekst i vitenarkiv
• Fardal, Øystein & Grytten, Jostein Ivar (2025). A Retrospective Study of Stabilizing Bridges in Patients With Stages III and IV Periodontitis: Up to 35 Years of Clinical Audit. Journal of Clinical Periodontology. ISSN 0303-6979. 52(6), s. 826–835. doi: 10.1111/jcpe.14116. Fulltekst i vitenarkiv
• Raittio, Eero; Grytten, Jostein Ivar; Fernandez, Nestor Rodrigo Lopez; Blich, Carl Christian; Vettore, Mario Vianna & Bælum, Vibeke (2024). Applying current European periodontitis clinical practice guidelines is not feasible even for the richest countries in the world. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. 53(1), s. 1–6. doi: 10.1111/cdoe.13003. Fulltekst i vitenarkiv Vis sammendrag

  Clinical practice guidelines aim to enhance the quality, equality and consistency of care but often demand more time than is available, rendering adherence impractical and exceeding feasible resources. The 2017 introduction of a new periodontal classification system by the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP) sought to refine clinical and epidemiological practices by serving as the basis for clinical practice guidelines and epidemiological investigations around the world. Following this classification, the EFP recommends supportive periodontal care visits every 3–12 months for all periodontitis cases. Given that in Norway, approximately 72% of the adult population are identified as periodontitis cases under the current AAP/EFP case definition, this poses a significant demand on healthcare resources. We calculated that between 60% and 70% of all estimated available working hours available for adult dental care provided by dentists and dental hygienists in Norway in 2017 would be spent on supportive periodontal care visits alone if the recommendations were to be met. This situation calls for a reevaluation of disease definitions and clinical practice guidelines to ensure they are practical, financially feasible and patient-outcome relevant.

• Linde, Astrid de; Grytten, Jostein Ivar; Skau, Irene & Kinge, Jonas Minet (2024). Maternity ward closures and infant health outcomes, maternal health outcomes, and birth procedures. HERO skriftserie / Working paper. ISSN 1501-9071. Fulltekst i vitenarkiv
• Holden, Mari Brekke; Skau, Irene & Grytten, Jostein Ivar (2024). Forbruket av tannhelsetjenester i voksenbefolkningen 20-70 år - mye kontroller og mindre behandling. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 134, s. 796–805. doi: 10.56373/2024-10-3. Fulltekst i vitenarkiv
• Eskild, Anne; Skau, Irene; Haavaldsen, Camilla; Saugstad, Ola Didrik & Grytten, Jostein Ivar (2024). Short inter-pregnancy interval and birthweight: a reappraisal based on a follow-up study of all women in Norway with two singleton deliveries during 1970–2019. European Journal of Epidemiology (EJE). ISSN 0393-2990. 39(8), s. 905–914. doi: 10.1007/s10654-024-01148-y. Fulltekst i vitenarkiv Vis sammendrag

  We studied mean changes in birthweight from the first to the second delivery according to length of the inter-pregnancy interval. We also studied recurrence risk of low birthweight, preterm birth and perinatal death. We followed all women in Norway from their first to their second singleton delivery at gestational week 22 or beyond during the years 1970–2019, a total of 654 100 women. Data were obtained from the Medical Birth Registry of Norway. Mean birthweight increased from the first to the second delivery, and the increase was highest in pregnancies conceived < 6 months after the first delivery; adjusted mean birthweight increase 227 g (g) (95% CI; 219–236 g), 90 g higher than in pregnancies conceived 6–11 months after the first delivery (137 g (95% CI; 130–144 g)). After exclusion of women with a first stillbirth, the mean increase in birthweight at inter-pregnancy interval < 6 months was attenuated (152 g, 95% CI; 143–160 g), but remained higher than at longer inter-pregnancy intervals. This finding was particularly prominent in women > 35 years (218 g, 95% CI; 139 –298 g). In women with a first live born infant weighing < 2500 g, mean birthweight increased by around 1000 g to the second delivery, and the increase was most prominent at < 6 months inter-pregnancy interval. We found increased recurrence risk of preterm birth at inter-pregnancy interval < 6 months, but no increased recurrence risk of low birthweight, small for gestational age infant or perinatal death. In conclusion, we found the highest mean increase in birthweight when the inter-pregnancy interval was short. Our results do not generally discourage short pregnancy intervals.

• Hussain, Badra; Grytten, Jostein Ivar; Rongen, Gunnar; Alonso, Mariano Sanz & Haugen, Håvard Jostein (2024). Surface Topography Has Less Influence on Peri-Implantitis than Patient Factors: A Comparative Clinical Study of Two Dental Implant Systems. ACS Biomaterials Science and Engineering. 10(7), s. 4562–4574. doi: 10.1021/acsbiomaterials.3c01809. Fulltekst i vitenarkiv Vis sammendrag

  Objectives: This study aims to assess the risk of peri-implantitis (PI) onset among different implant systems and evaluate the severity of the disease from a population of patients treated in a university clinic. Furthermore, this study intends to thoroughly examine the surface properties of the implant systems that have been identified and investigated. Material and methods: Data from a total of six hundred and 14 patients were extracted from the Institute of Clinical Dentistry, Dental Faculty, University of Oslo. Subject- and implant-based variables were collected, including the type of implant, date of implant installation, medical records, recall appointments up to 2022, periodontal measurements, information on diabetes, smoking status, sex, and age. The outcome of interest was the diagnosis of PI, defined as the occurrence of bleeding on probing (BoP), peri-implant probing depth (PD) ≥ 5 mm, and bone loss (BL). Data were analyzed using multivariate linear and logistic regression. Scanning electron microscopy, light laser profilometer, and X-ray photoelectron spectroscopy were utilized for surface and chemical analyses. Results: Among the patients evaluated, 6.8% were diagnosed with PI. A comparison was made between two different implant systems: Dentsply Sirona, OsseospeedTM and Straumann SLActive, with mean follow-up times of 3.84 years (SE: 0.15) and 3.34 years (SE: 0.15), respectively. The surfaces have different topographies and surface chemistry. However, no significant association was found between PI and implant surface/system, including no difference in the onset or severity of the disease. Nonetheless, plaque control was associated with an increased risk of developing PI, along with the gender of the patient. Furthermore, patients suffering from PI exhibited increased BL in the anterior region. Conclusion: No differences were observed among the evaluated implant systems, although the surfaces have different topography and chemistry. Factors that affected the risk of developing PI were plaque index and male gender. The severity of BL in patients with PI was more pronounced in the anterior region. Consequently, our findings show that success in implantology is less contingent on selecting implant systems and more on a better understanding of patient-specific risk factors, as well as on implementing biomaterials that can more effectively debride dental implants.

• Janssen, Jip; Pöld, Ave; Islam, Md Monirul; Németh, Orsolya; Grytten, Jostein Ivar & Woods, Noel [Vis alle 7 forfattere av denne artikkelen] (2024). How to ensure an appropriate oral health workforce? Modelling future scenarios for the Netherlands. Human Resources for Health. 22(1). doi: 10.1186/s12960-024-00957-2. Fulltekst i vitenarkiv Vis sammendrag

  Background Current methods for oral health workforce planning lack responsiveness to dynamic needs, hampering efficiency, equity and sustainability. Effective workforce planning is vital for resilient health care systems and achieving universal health coverage. Given this context, we developed and operationalised a needs-adaptive oral health workforce planning model and explored the potential of various future scenarios. Methods Using publicly available data, including the Special Eurobarometer 330 Oral Health Survey, we applied the model in a hypothetical context focusing on the Dutch population’s dental needs from 2022 to 2050. We compared current and future provider supply and requirement and examined, in addition to a base case scenario, several alternative scenarios. These included epidemiological transition scenarios with different oral health morbidity trajectories, skill-mix scenarios with independent oral hygienists conducting check-ups and multiple dental student intake and training duration (5 instead of 6 years) scenarios. Results Based on the aforementioned historical data, our model projects that provider requirement will exceed supply for the planning period. If the percentage of people having all natural teeth increases by 10% or 20% in 2032, 34 or 68 additional full-time equivalent (FTE) dentists will be required, respectively, compared to the base case scenario. In the skill-mix scenario, the model indicates that prioritising oral hygienists for check-ups and shifting dentists’ focus to primarily complex care could address population needs more efficiently. Among the student intake and training duration scenarios, increasing intake to 375 and, to a lesser extent, reducing training to 5 years is projected to most effectively close the provider gap. Conclusions The study underscores the importance of understanding oral health morbidity trajectories for effective capacity planning. Due to limited dental epidemiological data, projections carry substantial uncertainty. Currently, demand for FTE dentists seems to exceed supply, though this may vary with epidemiological changes. Skill-mix strategies could offer efficiency gains by redistributing tasks, while adjustments in dental intake and training duration could also help address the requirement-supply gap. Resolving dentistry workforce challenges requires a multifaceted approach, including strengthening oral epidemiology projections, addressing the root causes of dental health issues and prioritising harmonious dental public health and general practice prevention measures.

• Grytten, Jostein Ivar; Skau, Irene & Sørensen, Rune Jørgen (2023). Fertility and immigration: Do immigrant mothers hand down their fertility pattern to the next generation? Evidence from Norway. Economics and Human Biology. ISSN 1570-677X. 52. doi: 10.1016/j.ehb.2023.101339. Fulltekst i vitenarkiv Vis sammendrag

  We examined whether the fertility pattern of immigrant mothers is handed down to the next generation. Our analyses were carried out on population register data. These data contained information on all immigrants to Norway from 123 countries during the period 1935–1995. We examined whether there was a relationship between the fertility rate in the country of origin and the number of children for generations 1.5 and 2 in Norway. We estimated three models: fixed effects for country of origin, fixed effects for region, and no fixed effects. The three specifications yielded estimates with overlapping confidence intervals. We interpret the estimates from the models with fixed effects for region, and the model with no fixed effects as upper-bound estimates. They show that an increase of 1.00 in the fertility rate in the country of origin leads to an average increase in the number of children of 0.12 (no fixed effects) or 0.14 (fixed effects for region) for immigrant women in generations 1.5 and 2. The estimate from the model with fixed effects for country of origin was small and not statistically significant at the conventional level. We interpret this as a lower-bound estimate. Our upper-bound estimates for generations 1.5 and 2 are smaller than the estimates for generation 1, i.e. there has been a decrease in the fertility rate from the first to the second generation. As a result, if the proportion of the population with an immigrant background continues to increase, it may increase at a slower rate in the future.

• Jiang, Nan; Kinge, Jonas Minet; Skau, Irene & Grytten, Jostein Ivar (2023). Reduserer subsidiert kjeveortopedisk behandling ulikheter i tilgang? Funn fra Norge basert på folkeregisterdata. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 133, s. 906–906. Fulltekst i vitenarkiv
• Jiang, Nan; Kinge, Jonas Minet; Skau, Irene & Grytten, Jostein Ivar (2023). Does subsidized orthodontic treatment reduce inequalities in access? Evidence from Norway based on population register data. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. doi: 10.1111/cdoe.12918. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Objective An important part of Norwegian welfare policy is to provide subsidized orthodontic treatment for children and adolescents. The objective of this policy is that dental services should be allocated according to children's need for treatment, and not according to parents' ability to pay. The probability of receiving orthodontic treatment independent of parent's household income was examined. Methods The study population encompassed children and adolescents aged 10–18 years in 2019 ( n  = 354 439). Information about whether they had started orthodontic treatment was obtained from the Norwegian Health Economics Administration. The key independent variable was net equalized household income. Inequalities were measured using concentration indices, which were estimated according to the severity of the malocclusion (very great need, great need, obvious need and no need). Two indices were used to measure relative inequality: the unstandardized concentration index and the partial concentration index. Absolute inequality was measured using the corrected concentration index. Relevant control variables were included in some of the analyses. Results The unstandardized indices were in the range 0.04 (very great need) to 0.05 (obvious need). For all three groups of severity, the 95% confidence intervals overlapped. The values of the partial indices were significantly lower than the values of the unstandardized indices. The partial indices were in the range 0.008 (very great need) to 0.03 (obvious need). The 95% confidence intervals for the partial indices did not overlap with the 95% confidence intervals of the unstandardized indices. For all three groups of severity, the indices that measured absolute inequality were close to zero. Conclusions It is possible to achieve the egalitarian aim of equality in service provision by subsidizing orthodontic treatment. This is possible within a system where the cost of orthodontic treatment is reimbursed according to the criteria of need. These criteria function in such a way that patients with the greatest need for orthodontic treatment are given the highest priority.

• Eskild, Anne; Skau, Irene; Grytten, Jostein Ivar & Haavaldsen, Camilla (2023). Inter-pregnancy interval and placental weight. A population based follow-up study in Norway. Placenta. ISSN 0143-4004. 144, s. 38–44. doi: 10.1016/j.placenta.2023.11.003. Fulltekst i vitenarkiv Vis sammendrag

  Introduction We studied changes in placental weight from the first to the second delivery according to length of the inter-pregnancy interval. Methods We followed all women in Norway from their first to their second successive singleton pregnancy during the years 1999–2019, a total of 271 184 women. We used data from the Medical Birth Registry of Norway and studied changes in placental weight (in grams (g)) according to the length of the inter-pregnancy. Adjustments were made for year and maternal age at first delivery, changes in the prevalence of maternal diseases (hypertension and diabetes), and a new father to the second pregnancy. Results Mean placental weight increased from 655 g at the first delivery to 680 g at the second. The adjusted increase in placental weight was highest at inter-pregnancy intervals <6 months; 38.2 g (95 % CI 33.0g–43.4 g) versus 23.2 g (95 % CI 18.8g–27.7 g) at inter-pregnancy interval 6–17 months. At inter-pregnancy intervals ≥18 months, placental weight remained higher than at the first delivery, but was non-different from inter-pregnancy intervals 6–17 months. Also, after additional adjustment for daily smoking and body mass index in sub-samples, we found the highest increase in placental weight at the shortest inter-pregnancy interval. We estimated no difference in gestational age at delivery or placental to birthweight ratio according to inter-pregnancy interval. Discussion Placental weight increased from the first to the second pregnancy, and the increase was most pronounced at short inter-pregnancy intervals. The biological causes and implications of such findings remain to be studied.

• Fardal, Øystein; Skau, Irene & Grytten, Jostein Ivar (2023). A 30-year retrospective cohort outcome study of periodontal treatment of stages III and IV patients in a private practice. Journal of Clinical Periodontology. ISSN 0303-6979. 52, s. 102–112. doi: 10.1111/jcpe.13877. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Aim Tooth loss studies show that periodontal treatment is effective. However, it is not known whether these results can be projected into a lifetime of treatment. The aim of the study was to study all patients with stages III/IV of periodontitis over 30 years in a private practice. Materials and Methods All patients referred between 1986 and 1990 were monitored for 30 years for tooth loss and prognostic factors. All dropouts were accounted for. Results In all, 386 patients were followed, of whom 283 patients dropped out, leaving 103 patients (67 females and 36 males, average age 40.1 years) monitored over 30 years. Tooth loss was stable until 16 years, when the population was divided into groups of low ( n  = 65), moderate ( n  = 18) and high ( n  = 20) tooth loss, losing 1.05 (SD 1.27), 4.83 (SD 0.96) and 11.90 (SD 4.25) teeth, respectively. The strongest prognostic factors were first‐degree relatives with periodontitis, periodontal treatment before the age of 35 years, diabetes and patients with teeth with initial hopeless prognosis. Conclusion The majority of patients with stages III and IV periodontitis could be successfully treated with conventional periodontal treatment over a period of 30 years. The findings suggest that retrospective studies with shorter observation times cannot automatically be projected onto the outcome of a lifetime of periodontal treatment.

• Listl, S.; Ardenne, Ardenne van; Grytten, Jostein Ivar; Gyrd-Hansen, Dorte; Lang, H. & Melo, P. [Vis alle 14 forfattere av denne artikkelen] (2023). Prioritization, Incentives, and Resource Use for Sustainable Dentistry: The EU PRUDENT Project. JDR Clinical and Translational Research. ISSN 2380-0844. doi: 10.1177/23800844231189485. Fulltekst i vitenarkiv Vis sammendrag

  PRUDENT (Prioritization, incentives and Resource use for sUstainable DENTistry) is a multinational project funded under the European Union’s (EU’s) Horizon Europe program. Our team includes partners from Denmark, Estonia, France, Germany, Hungary, Ireland, Malta, the Netherlands, Norway, Portugal, and the United Kingdom; we aim to develop and implement an innovative and context-adaptive framework for optimal financing of oral health care that enables access to essential oral health care for everyone without causing financial hardship. PRUDENT will leverage health economics and implementation science methods to convert novel evidence on oral health financing into meaningful improvements of oral care. PRUDENT will harness behavioral experiments, system dynamics modeling, implementation trials, deliberative processes, and a multicountry monitoring framework on oral health care financing in the EU. Using a mixed-methods research design, PRUDENT addresses 3 objectives: (1) to develop a harmonized core set of oral health system indicators, implement them in a novel EU-wide monitoring system, and integrate them in deliberative processes to set priorities for oral care financing; (2) to identify optimization strategies for oral health care financing, in which real-world and lab experiments on provider payment and oral care insurance coverage, needs-adaptive resource planning, regulatory learning, and digital decision aid tools are leveraged to help accelerate transformations in oral care financing; and (3) to harness innovative knowledge transfer strategies for the co-development and co-production of sustainable implementation strategies for oral and general health care financing. Through improving access to essential oral care for everyone without causing financial hardship, PRUDENT is expected to help achieve universal health coverage for oral health. Knowledge Transfer Statement: The EU PRUDENT project aims to enhance the financing of oral health systems through novel evidence and implementation of better financing solutions together with citizens, patients, providers, and policy makers. The multicountry nature of the project offers unique windows of opportunity for rapid learning and improving within and across various contexts. PRUDENT is anticipated to strengthen capacities for better oral care financing in the EU and worldwide.

• Preus, Hans Ragnar; Aass, Anne Merete & Grytten, Jostein Ivar (2022). Munnhelse i sykehjem - en undersøkelse gjort i Akershus. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 132(4), s. 320–326. doi: 10.56373/2022-4-3. Fulltekst i vitenarkiv
• Blix, Ellen; Eskild, Anne; Skau, Irene & Grytten, Jostein Ivar (2022). The impact of the introduction of intrapartum fetal ECG ST segment analysis. A population study. Acta Obstetricia et Gynecologica Scandinavica. ISSN 0001-6349. 101(7), s. 809–818. doi: 10.1111/aogs.14347. Fulltekst i vitenarkiv Vis sammendrag

  Introduction ST segment analysis (STAN) of the fetal electrocardiogram was introduced as an adjunct to cardiotocography for intrapartum fetal monitoring 30 years ago. We examined the impact of the introduction of STAN on changes in the occurrence of fetal and neonatal deaths, Apgar scores of <7 at 5 min, intrapartum cesarean sections, and instrumental vaginal deliveries while controlling for time- and hospital-specific trends and maternal risk factors. Material and Methods Data were retrieved from the Medical Birth Registry of Norway from 1985 to 2014. Individual data were linked to the Education Registry and the Central Person Registry. The study sample included 1 132 022 singleton births with a gestational age of 36 weeks or beyond. Information about the year of STAN introduction was collected from every birth unit in Norway using a questionnaire. Our data structure consisted of a hospital-year panel. We applied a linear probability model with hospital-fixed effects and with adjustment for potentially confounding factors. The prevalence of the outcomes before and after the introduction of STAN were compared within each birth unit. Results In total, 23 birth units, representing 76% of all births in Norway, had introduced the STAN technology. During the study period, stillbirths declined from 2.6 to 1.9 per 1000 births, neonatal deaths declined from 1.7 to 0.7 per 1000 live births, babies with Apgar score <7 at 5 min after birth increased from 7.4 to 9.5 per 1000 births, intrapartum cesarean sections increased from 6.4% to 9.5%, and instrumental vaginal deliveries increased from 7.8% to 10.9%. Our analyses found that the introduction of STAN was not associated with the decline in proportion of stillbirths (p =0.76) and neonatal deaths (p =0.76) or with the increase in intrapartum cesarean sections (p =0.92) and instrumental vaginal deliveries (p =0.78). However, it was associated with the increased occurrence of Apgar score <7 at 5 min (p =0.01). Conclusions There is no evidence that the introduction of STAN contributed to changes in the rates of stillbirths, neonatal deaths, intrapartum cesarean sections, or instrumental vaginal deliveries. There was an association between the introduction of STAN and a small increase in neonates with low Apgar scores.

• Grytten, Jostein Ivar; Listl, Stefan & Skau, Irene (2022). Do Norwegian private dental practitioners with too few patients compensate for their loss of income by providing more services or by raising their fees? Community Dentistry and Oral Epidemiology. ISSN 0301-5661. s. 1–8. doi: 10.1111/cdoe.12750. Fulltekst i vitenarkiv Vis sammendrag

  Objective In Norway, supply of dental services exceeds demand, mainly because of the marked improvement in dental health during the last few decades. The aim of the study was to investigate whether private dental practitioners counteract a fall in demand for their services by providing more services or by raising their fees. Methods The data were collected using a questionnaire that was sent to all private dental practitioners in Norway. Altogether 1237 practitioners responded, which gave a response rate of 56%. Our sample was representative of the population of practitioners in Norway. As a measure of patient supply, responses from the following questions were used: ‘Based on an overall assessment of economy, workload and other personal factors, is the number of regular patients adequate? If not, do you wish to have more patients, or fewer patients?’ The outcome variables were dental fees, length of recall interval and mean cost per visit. The data were analysed using ordinary least square regression and a linear probability model. The following characteristics of the private dental practitioners were included as control variables: age, gender, work experience in years and whether they worked in a solo practice. To test the robustness of the findings, a supplementary analysis with the patient as the unit of analysis was carried out, using survey data of Norwegians aged 20 years and older. Based on this survey, the relationship between population: dentist ratio and mean cost per dental visit were examined. Results Nearly 40% of all practitioners reported that they had too few patients. They compensated for their loss of income by raising their fees, by recalling their patients more often and by increasing the cost per visit. The finding in the supplementary analysis using survey data from patients was similar to the findings in the main analyses using survey data from private dental practitioners. Conclusion The findings show that practitioners have market power. They were able to counteract a fall in demand for their services by providing more services and by raising their fees. The dental profession should be encouraged to provide appropriate services, in the present situation where supply exceeds demand.

• Salvesen, Barbro Fostad; Grytten, Jostein Ivar; Rongen, Gunnar & Vandevska-Radunovic, Vaska (2022). Patient‐reported outcome measures on oral hygiene, periodontal health, and treatment satisfaction of orthodontic retention patients up to ten years after treatment—A cross‐sectional study. International Journal of Environmental Research and Public Health (IJERPH). ISSN 1661-7827. 19(8), s. 1–10. doi: 10.3390/ijerph19084843. Fulltekst i vitenarkiv Vis sammendrag

  Background: This cross-sectional study evaluated patient-reported outcome measures (PROMs) on (1) oral hygiene, (2) periodontal health, (3) retainer failure, (4) orthodontic treatment satisfaction, and (5) outcome satisfaction in orthodontic retention patients. The purpose of the study was to evaluate whether orthodontic retention treatment is associated with patient-reported outcome measures on oral hygiene, periodontal health, and treatment satisfaction. Methods: A ten-item questionnaire on the five PROMs was conducted among 211 consecutive retention patients up to ten years following orthodontic treatment. Linear regression models were computed to detect possible associations between the PROMs and retention treatment or patient characteristics. Results: The presence of a fixed lingual retainer was not associated with the reduced ability to perform oral hygiene, self-perceived periodontal health, or orthodontic outcome satisfaction. Older patients were more content with the orthodontic treatment result (p &lt; 0.05). Patients with fixed lingual retainers in the mandible were less satisfied with the course of orthodontic treatment (p &lt; 0.05). Smokers more often reported gingival bleeding (p &lt; 0.05). Females reported increased gingival recessions (p &lt; 0.05) and perceived their teeth as longer than before treatment (p &lt; 0.05). Longer orthodontic treatment duration corresponded to retainer failure (p &lt; 0.05). Conclusions: In general, long-term orthodontic retention patients were satisfied with orthodontic treatment. These patients reported the satisfactory ability to perform adequate oral hygiene and periodontal health, and they communicated a high degree of treatment and outcome contentment. However, patients with a retainer in the mandible were less satisfied with orthodontic treatment.

• Fardal, Øystein; Skau, Irene; Nevland, Kristian & Grytten, Jostein Ivar (2021). Proposing a model for auditing data quality of long-term periodontal outcome studies. Acta Odontologica Scandinavica. ISSN 0001-6357. 80(5), s. 375–381. doi: 10.1080/00016357.2021.2020895. Fulltekst i vitenarkiv Vis sammendrag

  Objective The assessment of the success of conventional periodontal therapy is based on retrospective studies from private practice and university clinics. Due to their marked heterogeneity, it is difficult to assess the data quality and rate these studies. The aim is to test a model for auditing and rating the data quality of periodontal outcome studies. Methods The method was adapted from the NIH Health Care Systems Collaboratory model, which uses three data quality dimensions: completeness (including all the relevant variables), consistency (ensuring that the same variables are compared) and accuracy (proportion of data in error with a gold standard). The model was applied to studies from a Norwegian specialist practice and data from the Norwegian Health database to test if the auditing process was workable using real world data. Results Forty-seven risk and prognostic factors were included for completeness. Seven variables were specified for consistency: tooth loss, smoking, systemic conditions, oral hygiene, individual tooth prognosis, maintenance profiles and timing of extractions. The factors tested showed a 95.7% completeness and an average accuracy deviation from the gold standard of −2.3% for each of the risk/prognostic factors and an overall study score of 93.3%. Conclusions It was possible to develop a method for auditing and rating the quality of periodontal outcome studies. The model was tested using both real world data including risk and prognostic factors from individual outcome studies and national big data. The application of the model to these sets of data showed a high accuracy of the risk/prognostic factors and a close relationship with national big data.

• Grytten, Jostein & Skau, Irene (2021). Improvements in Dental Health and Dentists’ Workload in Norway, 1992 to 2015. International Dental Journal. ISSN 0020-6539. doi: 10.1016/j.identj.2021.07.004. Fulltekst i vitenarkiv Vis sammendrag

  Objectives There has been a marked improvement in dental health in Norway during the last few decades. What effect has this had on provision of dental services, and how has private dental practitioners’ assessment of their workload changed? Methods The data were from 2 large surveys of private dental practitioners carried out in 1992 (n = 1056) and 2015 (n = 1237). An analysis of nonresponders showed that they were evenly distributed according to their age, gender, and the region in which their practice was located. Thus, the samples were representative of private dental practitioners. For 1 representative week in practice, the practitioners were asked to report the number of visits and the number of patients who received 1 or more of the following items of treatment: filling, crown, bridge, denture, root filling, extraction, and periodontal treatment. As a measure of patient supply, the responses from the following questions were used: “Based on an overall assessment of economy, workload, and other personal factors, is the number of regular patients adequate? If not, do you wish to have more patients or fewer patients?” Results From 1992 to 2015, the annual number of visits per practitioner decreased by 23%. The number of patients per practitioner who received fillings, crowns, bridges, dentures, root fillings, or extractions decreased by 50% or more. The decrease was largest for practitioners younger than 35 years and for men. The proportion of practitioners who reported a deficit of patients increased from 20% to 37%. Conclusions Many dentists will have too few patients and a fall in income in the years to come is expected.

• Grytten, Jostein Ivar; Skau, Irene & Eskild, Anne (2021). Does the use of Doppler ultrasound reduce fetal mortality? A population study of all deliveries in Norway 1990-2014. International Journal of Epidemiology. ISSN 0300-5771. 50(6), s. 2038–2047. doi: 10.1093/ije/dyab098. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Background The aim of the present study was to examine the effect that the introduction of Doppler ultrasound in obstetric care has had on fetal death in Norway. One mechanism by which Doppler ultrasound may reduce fetal death may be through the increased use of Caesarean delivery. Therefore, we also examined the effect that the use of Doppler ultrasound has had on the use of Caesarean delivery. Methods The Medical Birth Registry of Norway provided detailed medical information for ∼1.2 million deliveries from 1990 to 2014. Information about the year of introduction of Doppler ultrasound was collected directly from the maternity units, using a questionnaire. The data were analysed using a hospital fixed-effects regression model with fetal death as the outcome measure. The key independent variable was the introduction of Doppler ultrasound at each maternity ward. Hospital-specific trends and risk factors of the mother for fetal death were included as covariates. Results For pre-term deliveries, the introduction of Doppler ultrasound contributed to a reduction in fetal death of ∼30% and to an increase in planned Caesarean section of ∼15%. There were no effects for emergency Caesarean sections or inductions pre-term. The introduction of Doppler ultrasound had no effect on fetal death or Caesarean section for term deliveries. Conclusions The introduction of Doppler ultrasound during the 1990s and 2000s made a significant contribution to the decline in the number of pre-term fetal deaths in Norway. Increased use of Caesarean section may have contributed to this reduction.

• Grytten, Jostein Ivar (2021). Befolkningens utdanning og tilgjengelighet til trygdefinansiert tannpleie i Norge. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 131, s. 24–30. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2021). Forbedringer i tannhelsen og tannlegenes arbeidsmengde i Norge 1992-2015. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 131( ), s. 1014–1015. Fulltekst i vitenarkiv
• Jiang, Nan; Grytten, Jostein & Kinge, Jonas Minet (2021). Inequality in access to dental services in a market-based dental care system: A population study from Norway 1975–2018. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. doi: 10.1111/cdoe.12709. Fulltekst i vitenarkiv Vis sammendrag

  Objective To examine income-related inequalities in access to dental services from 1975 to 2018. In Norway, dental care services for adults are privately financed. This may lead to income-related inequalities in access. In the early 1970s, that is, at the beginning of the study period, there were marked inequalities in access to dental services according to personal income. However, from the beginning of the 1970s, there has been a large increase in gross national income per capita in Norway as a result of the growth of the oil and gas industry. This increase in income also meant that people with a low income in 1975 had a rise in their level of income. According to the law of diminishing utility, an increase in income leads to higher consumption of dental services for people with a low level of income compared to people with a high level of income. The study hypothesis is that the inequalities in access to dental services that existed in 1975 became less over time. Methods Statistics Norway collected samples of cross-sectional health survey data for the following years: 1975, 1985, 1995, 2002, 2008, 2012 and 2018. For each sample, individuals 21 years and older were drawn randomly from the non-institutionalized adult population using a two-stage stratified cluster sample technique. Inequalities were measured using the concentration index. The dependent variable was the use of dental services during the last year, and the key independent variable was equivalized household income. Results The concentration index for inequalities in use of dental services according to income decreased from 0.10 (95% CI = 0.09, 0.11) in 1975 to 0.04 (95% CI = 0.03, 0.05) in 2018. The decrease was particularly large from 2002 to 2012. This was a period with a large growth in gross national income. Conclusion People with a low income had a marked increase in their purchasing power from 1975 to 2018. This coincided with an increase in demand for dental care for this low-income group.

• Eskild, Anne; Skau, Irene; Haavaldsen, Camilla & Grytten, Jostein Ivar (2021). A.Eskild og medarbeiderne svarer. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 141(12). doi: 10.4045/tidsskr.21.0584. Fulltekst i vitenarkiv
• Salvesen, Barbro Fostad; Grytten, Jostein; Rongen, Gunnar; Koldsland, Odd Carsten & Vandevska-Radunovic, Vaska (2021). Periodontal status in long-term orthodontic retention patients up to 10 years after treatment – a cross-sectional study. Acta Odontologica Scandinavica. ISSN 0001-6357. 79(8), s. 623–629. doi: 10.1080/00016357.2021.1921842. Fulltekst i vitenarkiv Vis sammendrag

  Objective To assess periodontal status in long-term orthodontic retention patients and investigate possible risk indicators. Materials and Methods Plaque index (PI), gingival index (GI), probing pocket depth (PPD), gingival recessions (GR) and calculus were recorded in 211 patients with or without fixed retainers. Results Periodontal parameters were within the limits of clinically healthy periodontium. The use of fixed retainers was associated with higher PI in the maxilla (ß = 1.10 [0.37]; p <.05). Older age was associated with higher PI in the mandible (ß = 0.27 [0.11]; p <.05). Smoking was associated with gingival bleeding on both palatal (ß = 0.63 [0.16]; p < .01) and labial sides in the maxilla (ß = 0.46 [0.20]; p <.05). Smoking was also associated with increased prevalence of GR in the mandible (ß = 0.24 [0.07]; p <.01), while use of snuff had similar effect on the labial side in the maxilla (ß = 0.35 [0.08]; p <.01). Higher age (ß = 0.05 [0.02]; p <.05) and the presence of a retainer (ß = 0.23 [0.07]; p < .05) were associated with calculus accumulation on the lingual side in the mandible. Conclusion The present observational study suggest that long-term fixed retainers alone have no detrimental effect on the periodontium. Additional factors may increase the risk of plaque deposits and increased probing pocket depths. Further prosepective studies are needed to confirm the present outcome.

• Kinge, Jonas Minet & Grytten, Jostein Ivar (2021). The impact of primary care physician density on perinatal health: Evidence from a natural experiment. Health Economics. ISSN 1057-9230. 30(12), s. 2974–2994. doi: 10.1002/hec.4426. Fulltekst i vitenarkiv Vis sammendrag

  We examined the impact of primary care physician density on perinatal health outcomes in Norway. From 1992 and onwards, primary care physicians who chose to work in selected remote municipalities were given an annual reduction in their student loan. This reduction, combined with increased supply of physicians, led to an increase in the density of primary care physicians in these selected municipalities. Our register-based population study showed that this increase in physician density significantly improved perinatal health in terms of fewer fetal deaths and increased birth weight. The richness of the data allowed us to perform several robustness tests.

• Grytten, Jostein Ivar; Skau, Irene & Sørensen, Rune Jørgen (2020). Who dies early? Education, mortality and causes of death in Norway. Social Science and Medicine. ISSN 0277-9536. 245. doi: 10.1016/j.socscimed.2019.112601. Fulltekst i vitenarkiv Vis sammendrag

  We estimated the effects of education on mortality and causes of death in Norway. We identified causal effects by exploiting the staggered implementation of a school reform that increased the length of compulsory education from seven to nine years. The municipality-level education data were combined with complete records of all deaths from 1960 to 2015 from the Norwegian Cause of Death Registry. These data covered the entire life span of persons aged 16–64. One additional year of education caused a reduction in mortality of about 10% for men. The effect was negligible for women. For men, a large part of the effect was due to fewer accidental deaths. We suggest two explanations for this finding. First, there are differences in risk-taking behaviour between people with a high level of education and those with a low level. Second, more education leads to upward occupational mobility. This mobility is mainly from occupations for which the risk of accidents is high to occupations for which the risk is low. Our results supported the fundamental cause theory. This is because education had a stronger effect on mortality for causes of death that are preventable than for causes of death that are not preventable. More education had no effect on the probability of dying of diseases that were amenable to medical intervention only. This gives some support to our results that patients are treated equally, independent of their level of education. This may be due to the large public involvement in financing and provision of health services.

• Fardal, Øystein; Skau, Irene; Rongen, Gunnar; Heasman, Peter & Grytten, Jostein Ivar (2020). Treatment provision of periodontal diseases in Norway in 2013 - a national profile. International Dental Journal. ISSN 0020-6539. 70(4), s. 266–276. doi: 10.1111/idj.12565. Fulltekst i vitenarkiv Vis sammendrag

  Background Epidemiological studies have reported high levels of periodontal diseases worldwide. Over the last 40 years, Norway has introduced several measures including major financial support to reduce periodontal diseases. The aims of this study were to establish the present level of periodontal treatment, the treatment profiles for the nation, and to assess if long‐term clinical data support the findings. Materials and methods The database of the Norwegian Health Economic Administration for 2013 was analysed to establish the prevalence of treated periodontitis in a cross‐sectional register‐based study. Treatment profiles including patients' ages, gender, geographic distributions, treatment types, prosthetic tooth replacements and the treatment distributions between the dental health professionals were assessed. Results 4.4% of the 20 years and older age group was treated for periodontitis. More females (55%) than males (45%) were treated with predominance in the 60–69 year age group. Private general dental practitioners performed 43.8% of the total periodontal treatment, while dental hygienists performed 22.5%. Periodontists performed 32.8% of the non‐surgical and 74.6% of the surgical treatment. Tooth replacements for teeth lost due to periodontal diseases were provided for 0.57% of the population. Clinical studies from Norway showed marked improvements in the periodontal parameters examined over the last 40 years. Conclusion The frequency of periodontal treatments in Norway was low, but sufficient to maintain major tooth retention for the population. Long‐term external clinical data supported these findings. The treatments were well distributed between private general dental practitioners, hygienists and periodontists.

• Grytten, Jostein Ivar; Pervaiz, Maryam; Rongen, Gunnar & Skau, Irene (2020). De unge voksnes tannhelse - hvor stort er deres behandlingsbehov? En analyse av studenter som var pasienter hos SiO Helse Tannlege i perioden 2007-2018. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 130, s. 904–912. Fulltekst i vitenarkiv
• Fardal, Øystein; Skau, Irene; Rongen, Gunnar; Heasman, Peter & Grytten, Jostein Ivar (2020). Provision of treatment for periodontitis in Norway in 2013 – a national profile. International Dental Journal. ISSN 0020-6539. 70(4), s. 266–276. doi: 10.1111/idj.12565. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2020). Educational inequalities in access to fixed prosthodontic treatment in Norway. Causal effects using the introduction of a school reform as an instrumental variable. Social Science and Medicine. ISSN 0277-9536. 260. doi: 10.1016/j.socscimed.2020.113105. Fulltekst i vitenarkiv Vis sammendrag

  Objectives Equality in access to dental services, independent of level of education, is an important aim of Scandinavian welfare policy. In Norway, this policy is the main justification for a dental public subsidy scheme for adults. An important part of the subsidy scheme is to cover the cost of fixed prosthodontic treatment, including implant-based crowns and bridges for premolars, canines and incisors. A stated policy goal is to secure equal access to everybody in need of these services, independent of their level of education. The aim of this study was to estimate the causal effect of education on the probability of receiving fixed prosthodontic treatment in the adult Norwegian population. Methods During the period 1960–1972, all municipalities in Norway were required to increase the number of compulsory years of education from seven to nine years. We used this education reform as the instrumental variable to create exogenous variation in the individual's number of years of education. The education data were combined with data from the Norwegian Health Economics Administration, which contained our outcome variable. Our sample included individuals with 9 years education or less. Altogether 113 237 individuals were included in the study. Results For men, the first stage regression coefficient was 0.87 (confidence interval: 0.82–0.92). This means that the reform resulted in 0.87 additional years of education. For men, the probability of receiving fixed prosthodontic treatment increased by 0.67 percentage points per additional year of schooling. For women, the first stage regression coefficient was 0.84 (confidence interval: 0.79–0.88). The second stage regression coefficient was small (= 0.0022) and not statistically significant at a conventional level. Conclusion From a welfare policy point of view, for men, the subsidy scheme has not succeeded to redistribute resources so that dental services are accessible independent of their social status.

• Fardal, Øystein; Skau, Irene & Grytten, Jostein Ivar (2020). Familial tendency as a determinant of tooth loss during long-term periodontal therapy. Journal of Clinical Periodontology. ISSN 0303-6979. 47(2), s. 213–222. doi: 10.1111/jcpe.13219. Fulltekst i vitenarkiv Vis sammendrag

  Aim Little evidence exists on how familial tendencies affect the long‐term success of periodontal therapy. The aim of this study was to compare outcomes for two generations and their control patients treated in the same private practice. Materials/methods Parents and their children were observed for tooth loss between 1986 and 2017. Matching control groups were identified from the same practice, one for the parent and one for the children group. The control patients had no close family members with a history of periodontal diseases. Both the generations and control groups completed a similar course of periodontal therapy. The matching strategy aimed at making the groups as similar as possible with respect to well‐known risk and prognostic factors. The data were analysed by multiple regression where the outcome was the number of teeth lost due to periodontal disease. Results A total of 435 patients were identified (148 parents, 154 children and 133 controls). 72 parents and 61 children (133) had more than 5 years follow‐up (average 15.5 and 12.9 years, respectively). Balancing tests showed that the matching was successful. 65% of tooth loss was attributable to close family history. The regression showed that the parent generation lost 1.02 more teeth than the controls, while the children lost 0.61 more teeth. Conclusion Having close family members with a history of periodontal diseases is a strong prognostic factor affecting the long‐term outcome of periodontal therapy.

• Grytten, Jostein Ivar; Bukholm, Ida Rashida Khan; Blich, Carl Christian; Rongen, Gunnar & Skau, Irene (2019). Norsk pasientskadeerstatning - diagnostikk og behandlingssvikt. En oversikt. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 129, s. 1088–1095. Fulltekst i vitenarkiv
• Listl, Stefan; Grytten, Jostein Ivar & Birch, Stephen (2019). What is health economics? Community Dental Health. ISSN 0265-539X. 36(4), s. 263–275. doi: 10.1922/CDH_4581Listl13. Fulltekst i vitenarkiv
• Eskild, Anne; Sommerfelt, Silje; Skau, Irene & Grytten, Jostein Ivar (2019). Offspring birthweight and placental weight in immigrant women from conflict-zone countries; does length of residence in the host country matter? A population study in Norway. Acta Obstetricia et Gynecologica Scandinavica. ISSN 0001-6349. s. 1–8. doi: 10.1111/aogs.13777. Fulltekst i vitenarkiv Vis sammendrag

  Introduction We aimed to estimate differences in offspring birthweight and placental weight between Norwegian women and immigrants in Norway from countries with armed conflicts. We also studied whether length of residence in Norway was associated with offspring birthweight and placental weight. Material and methods We included in our study all singleton births in Norway at gestational week 28 or beyond during the years 1999‐2014, to mothers who were born in Somalia, Afghanistan, Iraq (total immigrants n = 18 817), or Norway (n = 668 439). Data were obtained from The Medical Birth Registry of Norway and the Central Person Registry of Norway. We estimated the differences between Norwegian and immigrant women in mean offspring birthweight and mean placental weight by applying linear regression analyses. Adjustments were made for maternal age, parity, year of delivery, gestational age at delivery, preeclampsia, and diabetes. Results The immigrant women had 206 g (95% CI 199 to 213 g) lower mean offspring birthweight and 16 g (95% CI 14 to 18 g) lower mean placental weight than Norwegian women. Immigrant women with ≥5 years of residence in Norway had higher offspring birthweight (40 g) and higher placental weight (17 g) than immigrant women with <5 years of residence. Conclusions Immigrant mothers from Somalia, Afghanistan, and Iraq gave birth to infants and placentas with lower weight than Norwegian women. However, the difference between Norwegian women and immigrant women was reduced by length of residence in Norway.

• Emrani, Reza; Sargeran, Katayoun; Grytten, Jostein Ivar & Hessari, Hossein (2019). A Survey of Common Payment Methods and Their Determinants in Dental Clinics, in Tehran, 2018. European Journal of Dentistry. ISSN 1305-7456. 13(4), s. 535–539. doi: 10.1055/s-0039-1697556. Fulltekst i vitenarkiv Vis sammendrag

  Objective It is believed that the payment method to dentists may affect their treatment decisions. Although payment systems may enhance job satisfaction, reduce the costs, and make better treatment decisions, there is little information about how to achieve these objectives. The aim of the present study was to survey the payment methods and the related factors in dental clinics of Tehran. Materials and Methods Using the latest list published by the Iranian Ministry of Health, we visited all dental clinics located in Tehran, and used a checklist to collect the data of the type of management, geographical location of the clinic in Tehran, payment method and its amount, history of payment method changes in the last decade, relationship between the amount of payment and the position of technical supervisor dentist, any difference in the amount of payment to male and female dentists and to young and experienced dentists. Then, the relationship between the amount of payment and the above-mentioned variables was investigated. Results The governmental sector tends to use fixed salary methods and the private sector usually uses the fee-for-service (FFS) method. Geographical location, type of management, date of establishment, and having the position of technical supervisor dentist had a significant relationship with the amount of payment. The dentist’s gender and years of experience did not have any relationship with the amount of payment. Conclusion According to the results of the present study, the method and amount of payment to dentists were related to the date of clinic establishment, having the position of technical supervisor dentist, and geographical location of the clinic. These factors could be considered as the main elements in balancing costs in clinics and improving job satisfaction among dentists.

• Fardal, Øystein; Grytten, Jostein Ivar; Martin, John; Ellingsen, Stig; Fardal, Patrick & Heasman, Peter [Vis alle 7 forfattere av denne artikkelen] (2018). Adding smoking to the Fardal model of cost‐effectiveness for the lifetime treatment of periodontal diseases. Journal of Periodontology. ISSN 0022-3492. 89(11), s. 1283–1289. doi: 10.1002/JPER.17-0467. Fulltekst i vitenarkiv Vis sammendrag

  Background Little is known about the financial costs that smoking adds to the lifetime treatment of periodontal disease. Methods The total lifetime cost of periodontal treatment was modeled using data from private periodontal practice. The costs of initial and supportive therapy, re‐treatment and tooth replacements (with bridgework or implants) were identified using average dental charges from the American Dental Association survey. Smoking costs at $6 and $10 for 20 cigarettes were compared to the costs of lifetime periodontal treatment for stable and unstable compliant patients. Results Smoking added 8.8% to the financial cost of the lifetime cost of periodontal therapy in stable maintenance patients, 40.1% in patients who needed one extra maintenance visit, and 71.4% in patients who needed two extra maintenance visits per year in addition to added retreatment. The cost of smoking far exceeded the cost of periodontal treatment; For patients who smoked 10 to 40 cigarettes per day at the cost of $6 or $10 a pack, the cost of smoking exceeded the cost of lifetime periodontal treatment by between 2.7 and 17.9 times. Smoking 40 cigarettes at $10 a packet for 3.4 years would pay for the entire lifetime cost of periodontal treatment. Conclusion Smoking adds considerable extra financial costs to the lifetime treatment of periodontal diseases. The cost of smoking itself exceeds the cost of periodontal therapy.

• Grytten, Jostein Ivar; Skau, Irene; Sørensen, Rune Jørgen & Eskild, Anne (2018). Does the Use of Diagnostic Technology Reduce Fetal Mortality? Health Services Research (HSR). ISSN 0017-9124. 53(6), s. 4437–4459. doi: 10.1111/1475-6773.12721. Fulltekst i vitenarkiv Vis sammendrag

  Objective: To examine the effect that the introduction of new diagnostic technology in obstetric care has had on fetal death. Data Source The Medical Birth Registry of Norway provided detailed medical information for approximately 1.2 million deliveries from 1967 to 1995. Information about diagnostic technology was collected directly from the maternity units, using a questionnaire. Study Design: The data were analyzed using a hospital fixed‐effects regression with fetal mortality as the outcome measure. The key independent variables were the introduction of ultrasound and electronic fetal monitoring at each maternity ward. Hospital‐specific trends and risk factors of the mother were included as control variables. The richness of the data allowed us to perform several robustness tests. Principal Finding: The introduction of ultrasound caused a significant drop in fetal mortality rate, while the introduction of electronic fetal monitoring had no effect on the rate. In the population as a whole, ultrasound contributed to a reduction in fetal deaths of nearly 20 percent. For post‐term deliveries, the reduction was well over 50 percent. Conclusion: The introduction of ultrasound made a major contribution to the decline in fetal mortality at the end of the last century.

• Grytten, Jostein Ivar & Skau, Irene (2018). Do Patients with More Education Receive More Subsidized Dental Care? Evidence from a Natural Experiment Using the Introduction of a School Reform in Norway as an Instrumental Variable. Medical Care. ISSN 0025-7079. 56(10), s. 877–882. doi: 10.1097/MLR.0000000000000976. Fulltekst i vitenarkiv Vis sammendrag

  Background: In Norway, for several dental conditions, a substantial part of treatment costs are reimbursed by the National Insurance Scheme. Ideally, the probability of receiving subsidized dental care (SDC) should be independent of social determinants of health, such as education, so that dental services are accessible to everyone independent of their social status. Objective: The main objective of this study was to estimate the causal effect of education on the probability of receiving SDC in the adult Norwegian population. Research Design: During the period 1960-1972, all municipalities in Norway were required to increase the number of compulsory years of education from 7 to 9 years. This education reform was used to create exogenous variation in the education variable. Since municipalities implemented the reform at different times, we have both cross-sectional and time series variation in the reform instrument. Thus we were able to estimate the effect of education on the probability of receiving SDC by controlling for municipality fixed effects and trend variables. Subjects: This study included all Norwegian adults, born during the period of 1947-1958. Measures: Information about education (number of years), whether the individuals had received SDC, place of residence (municipality) was collected. Results: The probability of receiving SDC was found to increase by 2 percentage points per additional year of education. Conclusion: People with the most resources benefit the most from a universal welfare scheme that is addressed to reach everybody. We suggest providing information about the subsidy scheme in a way that is easily available and understandable to all individuals, independent of their level of education.

• Preus, Hans Ragnar; Fredriksen, Karen Wanda; Vogsland, Andrea; Sandvik, Leiv & Grytten, Jostein Ivar (2017). Antibiotic-prescribing habits among Norwegian dentists: a survey over 25 years (1990-2015). European Journal of Oral Sciences. ISSN 0909-8836. 125(4), s. 280–287. doi: 10.1111/eos.12360. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2017). The impact of education on the probability of receiving periodontal treatment. Causal effects measured by using the introduction of a school reform in Norway. Social Science and Medicine. ISSN 0277-9536. 188, s. 128–136. doi: 10.1016/j.socscimed.2017.07.011. Fulltekst i vitenarkiv Vis sammendrag

  The aim of the present study was to estimate the causal effect of education on the probability of receiving periodontal treatment in the adult Norwegian population. In Norway, a substantial part of the cost of periodontal treatment is subsidized by the National Insurance Scheme. In that case, one might expect that the influence of individual resources, such as education, on receiving treatment would be reduced or eliminated. Causal effects were estimated by using data on a school reform in Norway. During the period 1960–1972, all municipalities in Norway were required to increase the number of compulsory years of schooling from seven to nine years. The education reform was used to create exogenous variation in the education variable. The education data were combined with large sets of data from the Norwegian Health Economics Administration and Statistics Norway. Since municipalities implemented the reform at different times, we have both cross-sectional and time-series variation in the reform instrument. Thus we were able to estimate the effect of education on the probability of receiving periodontal treatment by controlling for municipality fixed effects and trend variables. The probability of receiving periodontal treatment increased by 1.4–1.8 percentage points per additional year of schooling. This is a reasonably strong effect, which indicates that policies to increase the level of education in the population can be an effective tool to improve oral health, including periodontal health.

• Holmgren, Tonje Kristine; Rongen, Gunnar & Grytten, Jostein Ivar (2017). Allmenntannlegen i den private tannhelsetjenesten - har de nok å gjøre? Den norske tannlegeforenings Tidende. ISSN 0029-2303. 127(11), s. 948–952. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar; Skau, Irene & Sørensen, Rune Jørgen (2017). The impact of the mass media on obstetricians' behavior in Norway. Health Policy. ISSN 0168-8510. 121(9), s. 986–993. doi: 10.1016/j.healthpol.2017.07.007. Fulltekst i vitenarkiv Vis sammendrag

  Little is known about how physicians and hospitals respond to the risk of being negatively exposed in the mass media. We assume that newspapers will cover events more closely in the areas where they have most of their circulation. Within such areas the likelihood of negative publicity increases. The research question is whether obstetricians respond to negative newspaper coverage by choosing the least risky method of delivery, i.e. Caesarean section. This was tested on a large set of data from the Medical Birth Registry of Norway for the period 2000–2011. The Registry contains detailed medical information about all deliveries, for both the mother and the infant. This set of data was merged with a set of data that contained information about newspaper coverage for the municipalities in which all hospitals were located. Altogether, more than 620 000 deliveries in 46 municipalities were included in the study. The data were analyzed using a hospital fixed effects regression. The main result was that newspaper coverage had a significant positive effect on the probability of having a Caesarean section. Several supplementary analyses supported the main finding. Altogether, our results indicate that obstetricians are sensitive to the risk of being exposed in the mass media. This is likely to be because obstetricians care about their reputation.

• Grytten, Jostein Ivar (2017). The impact of education on dental health- ways to measure causal effects. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. 45, s. 485–495. doi: 10.1111/cdoe.12319. Fulltekst i vitenarkiv Vis sammendrag

  To our knowledge, there are no studies in which a possible causal effect of education on dental health has been examined. Such studies are needed to predict whether more schooling for people with poor dental health improves their dental health. Within social science, and in economics in particular, several methods have been developed to make causal inferences of the relationship between education and general health. These methods, which are based on observational data, are relevant to use for estimating a possible causal effect of education on dental health. This commentary provides an overview of the state of the art of the following methods: the use of instrumental variables, twin studies and a regression discontinuity design. Using these methods, reversed causality and the omission of a third variable that influences both education and dental health can be controlled for. In that way, an unbiased estimate of the effect of education on dental health can be obtained. To implement each of the methods correctly, several criteria have to be fulfilled. These criteria are outlined and discussed below. © 2017 Wiley

• Grytten, Jostein Ivar (2017). Payment systems and incentives in dentistry. Community Dentistry and Oral Epidemiology. ISSN 0301-5661. 45, s. 1–11. doi: 10.1111/cdoe.12267. Fulltekst i vitenarkiv Vis sammendrag

  In this commentary, we discuss the advantages and disadvantages of the following incentive-based remuneration systems in dentistry: fee-for-item fee-for-service remuneration, per capita remuneration, a mixed payment system (a combination of fee-for-item fee-for-service remuneration and per capita remuneration) and pay-for-performance. The two latter schemes are fairly new in dentistry. Fee-for-item Fee-for-service payments secure high quality, but lead to increased costs, probably due to supplier-induced demand. Per capita payments secure effectiveness, but may lead to under-treatment and patient selection. A mixed payment scheme produces results somewhere between over- and under-treatment. The prospective component (the per capita payment) promotes efficiency, while the retrospective component (the fee-for-service payment) secures high quality of the care that is provided. A pay-for-performance payment scheme is specifically designed towards improvements in dental health. This is done by linking provider reimbursements directly to performance indicators measuring dental health outcomes and quality of the services. Experience from general health services is that pay-for-performance payment has not been very successful. This is due to significant design and implementation obstacles, and lack of provider acceptance. A major criticism of all the incentive-based remuneration schemes is that they may undermine the dentists’ intrinsic motivation for performing a task. This is a crowding-out effect, which is particularly strong when monetary incentives are introduced for care that is cognitively demanding and complex, for example as in dentistry. One way in which intrinsic motivation may not be undermined, is to introduce a fixed salary component into the remuneration scheme. Dentists would then be able to choose their type of contract according to their abilities and their preferences for non-monetary rewards as opposed to monetary rewards. If a fixed salary component cannot be introduced into the remuneration scheme, the fees should be “neutral”; i.e. they should just cover the costs of the services provided. This is one way in which supplier-induced demand can be limited, and costs contained. © 2016 Wiley

• Holmgren, Tonje Kristine; Rongen, Gunnar & Grytten, Jostein Ivar (2017). De private spesialistene i tannhelsetjenesten - har de nok å gjøre? Den norske tannlegeforenings Tidende. ISSN 0029-2303. 127(11), s. 236–240. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar; Monkerud, Lars Chr.; Skau, Irene; Eskild, Anne; Sørensen, Rune Jørgen & Saugstad, Ola Didrik (2016). Saving Newborn Babies – The Benefits of Interventions in Neonatal Care in Norway over More Than 40 Years. Health Economics. ISSN 1057-9230. 26(3), s. 352–370. doi: 10.1002/hec.3314. Fulltekst i vitenarkiv Vis sammendrag

  The aim of this study was to examine the effect that the introduction of new medical interventions at birth has had on mortality among newborn babies in Norway during the period 1967–2011. During this period, there has been a significant decline in mortality, in particular for low birth weight infants. We identified four interventions that together explained about 50% of the decline in early neonatal and infant mortality: ventilators, antenatal steroids, surfactant and insure. The analyses were performed on a large set of data, encompassing more than 1.6 million deliveries (Medical Birth Registry of Norway). The richness of the data allowed us to perform several robustness tests. Our study indicates that the introduction of new medical interventions has been a very important channel through which the decline in mortality among newborn babies occurred during the second half of the last century.

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• Grytten, Jostein Ivar (2025). Models of financing dental care. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar; Sørensen, Rune Jørgen & Skau, Irene (2025). Maternal Education and Long-term Health Outcomes for the Next Generation. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2025). Is there overuse of orthodontic treatment among children in Norway? Fulltekst i vitenarkiv
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• Jiang, Nan; Skau, Irene; Choi, Hye Jung & Grytten, Jostein Ivar (2024). Covid-19: access to subsidized dental care for adults in Norway. Fulltekst i vitenarkiv
• Fardal, Øystein; Skau, Irene & Grytten, Jostein Ivar (2024). Periodontal Treatment of Norwegian Patients With Rare Diseases: A Commentary. International Dental Journal. ISSN 0020-6539. 74, s. 50–57. doi: 10.1016/j.identj.2023.07.009. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2024). Elderly people in Norway: demography, dental treatment needs and delivery of dental services. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2024). Mothers' level of education and infant health. Causal effects measured by using the introduction of a school reform. Fulltekst i vitenarkiv
• Fardal, Øystein; Skau, Irene & Grytten, Jostein Ivar (2024). Lang tids behandling av periodontitt bevarer tennene for de fleste pasienter. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 134, s. 212–213. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2023). Trygdefinansiering av tannhelsetjenesten - noen avveininger. Fulltekst i vitenarkiv
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• Grytten, Jostein Ivar & Skau, Irene (2023). Mothers' level of education and infant health. Causal effects measured by using the introduction of a school reform in Norway. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2023). Mothers' level of education and infant health. Causal effects measured by using the introduction of a school reform in Norway. Fulltekst i vitenarkiv
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• Grytten, Jostein Ivar; Blix, Ellen; Skau, Irene & Eskild, Anne (2022). STAN and fetal deaths. Acta Obstetricia et Gynecologica Scandinavica. ISSN 0001-6349. 101(12), s. 1460–1461. doi: 10.1111/aogs.14472. Fulltekst i vitenarkiv
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• Grytten, Jostein Ivar (2021). Innspill til strategidiskusjon NTF. Dagsaktuell politiske diskusjon – styrking av Den offentlige tannhelsetjenesten. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2021). Et endret samfunn og en endret profesjon – fra 1970-tallet til i dag. Fulltekst i vitenarkiv
• Kinge, Jonas Minet; Jiang, Nan & Grytten, Jostein Ivar (2021). Mindre ulikhet i tannhelsetjenesten. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2021). Hvordan identifisere årsakssammenhenger i ikke-eksperimentelle data? Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2020). Utdannes det for mange tannleger? Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2020). Education, mortality and causes of death. Fulltekst i vitenarkiv
• Blix, Ellen; Eskild, Anne; Skau, Irene & Grytten, Jostein Ivar (2019). Har innføringen av STAN-teknologien i Norge ført til færre dødfødsler, dødsfall hos nyfødte eller at færre barn blir født med lav apgar-skår? En populasjonstudie. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2019). Nasjonale registre i tannhelsetjenesten - hva har vi og hva trenger vi? Fulltekst i vitenarkiv
• Kinge, Jonas Minet & Grytten, Jostein Ivar (2019). Allmenndekningen og perinatal helse. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar & Skau, Irene (2019). Causal effect of education on receiving subsidized fixed prosthodontic treatment. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2018). Framtidens tannhelsetjeneste - noen utviklingstrekk. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2018). Do patients with more education receive more subsidized dental care? Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2018). Tannhelsetjenesten - prioritering og fordeling. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2018). Tannhelseforsikring - en realistisk finansieringsform for tannhelsetjenesten? Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2018). Tannhelsetjenesten - prioritering og fordeling. Fulltekst i vitenarkiv
• Preus, Hans Ragnar; Vogsland, Andrea; Fredriksen, Karen Wanda & Grytten, Jostein Ivar (2017). Norske tannlegers forskrivning av antibiotika : en undersøkelse over 25 år (1990-2015). Den norske tannlegeforenings Tidende. ISSN 0029-2303. 127(9), s. 782–789. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Tannhelsetjenestens framtid, men også et blikk på fortiden. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Tannhelsetjenesten - arbeidsmarkedet i privat sektor. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Tannhelsetjenestens framtid, med også et blikk på fortiden. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Does the use of diagnostic technology reduce fetal mortality? Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Does the use of diagnostic Technology reduce fetal mortality? Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Key note speaker: Payment systems and incentives in dentistry. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Use of diagnostic Technology ande fetal mortality. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2017). Tannhelsetjenesten - prioriteringer. Innledning til drøftingsmøte. Fulltekst i vitenarkiv
• Grytten, Jostein Ivar (2016). The impact of education on Health: ways to measure causal effects. Fulltekst i vitenarkiv

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