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Introduction: The Objective Structured Clinical Examination (OSCE) is a valid, reliable and reproducible assessment method traditionally carried out as a live examination but recently also provided online. The aim was to compare any differences in the perceptions of dental students participating in online and live OSCE using mixed methods., Materials and Methods: All Finnish fourth-year undergraduate dental students (n = 172) attended the exam in April 2021. Due to the COVID-19 pandemic, the official administrative restrictions in teaching in universities still existed in April 2021. By the time of the national OSCE, the pandemic situation varied in different parts of the country. Therefore, two of the universities conducted a live OSCE and two an online version of the OSCE. Data were collected after the OSCE using a voluntary anonymous electronic questionnaire with multiple-choice and open-ended questions (response rate 58%). Differences between the OSCE versions were analysed using the Mann-Whitney U test and open answers with qualitative content analysis., Results: The students considered both types of OSCE good in general. The main differences were found concerned adequate time allocation and overall technical implementation, in favour of the live OSCE. While a qualitative analysis revealed exam anxiety as the most often mentioned negative issue, overall, comments were positive., Conclusion: Variation in the assessments between different question entities seemed to be wider than between the implemented OSCE versions. Time management in the OSCE should be further developed by managing the assignment of tasks., (© 2023 The Authors. European Journal of Dental Education published by John Wiley & Sons Ltd.)

Introduction: The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) is part of the undergraduate dental curriculum. Online teaching has nowadays become common also in dentistry., Objective: To compare undergraduate students' self-assessed ability and satisfaction with learning DC/TMD Axis I between traditional and online learning and to evaluate the possible gains of online teaching., Material and Methods: Third-year undergraduate dental students in 2018 (traditional learning, Group 1, n = 43/50) and in 2019 (online learning, Group 2, n = 34/50) at the University of Oulu, Finland evaluated their self-assessed ability and satisfaction with learning DC/TMD clinical examination and diagnostics on a 10-point scale. Additionally, those participating in online courses answered to two open-ended questions; Group 2 (n = 50) and another group from the University of Eastern Finland in 2019 and 2020 (n = 75, Group 3). Total of 105/125 students (84%) responded. Content analysis was used to open-ended responses., Results: The online course reported significantly higher self-assessed ability in measurements (p = 0.004), identifying referred pain (p = 0.043) and statement for the diagnostics (p = 0.017) and also higher self-assessed satisfaction in measurements (p = 0.046). According to the content analysis, essential gains of online teaching were efficient learning, videos and exercises, and adjustability to own timetable., Conclusion: The online learning course can be considered as a good option for traditional learning of the DC/TMD protocol.

Mohammed M Gad,1 Shaimaa M Fouda,1,2 Fahad A Al-Harbi,1 Ritva Näpänkangas,2,3 Aune Raustia2,3 1Department of Substitutive Dental Sciences, College of Dentistry, University of Dammam, Dammam, Kingdom of Saudi Arabia; 2Research Unit of Oral Health Sciences, Faculty of Medicine, University of Oulu, Oulu, Finland; 3Medical Research Center, Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland Abstract: This paper reviews acrylic denture base resin enhancement during the past few decades. Specific attention is given to the effect of fiber, filler, and nanofiller addition on poly(methyl methacrylate) (PMMA) properties. The review is based on scientific reviews, papers, and abstracts, as well as studies concerning the effect of additives, fibers, fillers, and reinforcement materials on PMMA, published between 1974 and 2016. Many studies have reported improvement of PMMA denture base material with the addition of fillers, fibers, nanofiller, and hybrid reinforcement. However, most of the studies were limited to in vitro investigations without bioactivity and clinical implications. Considering the findings of the review, there is no ideal denture base material, but the properties of PMMA could be improved with some modifications, especially with silanized nanoparticle addition and a hybrid reinforcement system. Keywords: denture base, PMMA, reinforcement, nanoparticles, fibers, fillers

Objective: The purpose of this study was to assess how thermography findings relate painful symptoms and signs of temporomandibular disorders (TMD)., Methods: Thermography, combined with chewing of paraffin wax, was performed on 40 subjects. The results were analyzed according to gender and pain-related TMD symptoms and clinical signs., Results: The overall temperatures after chewing were higher in TMD patients than in controls. For females, the most significant findings were the thermal increase between the relaxed state and subjects' state after chewing in temporal and temporomandibular joint (TMJ) regions. For males, all calculated parameters demonstrated a poor ability to discriminate TMD from controls., Conclusion: Thermography could be a potential tool in diagnostics of female TMD patients. The results suggest that the thermal information assessed in specific facial areas could help to discriminate TMD patients from non-TMD patients and could be used to quantify the pain associated with TMD.

Background: Pain related to temporomandibular disorders (TMD) can be linked with multiple site pain (MSP), and may associate with increased pain sensitivity, more frequently among women than men. The aim of the study was to examine the associations of pressure pain threshold (PPT) and tolerance (PPTo) with TMD and associated MSP in the Northern Finland Birth Cohort 1966 (NFBC1966) study., Methods: Altogether 1961 NFBC1966 subjects attended clinical medical and dental examination at the Institute of Dentistry, University of Oulu in 2012-2013. Clinical examinations were carried out using a modified Diagnostic Criteria for TMD protocol (DC/TMD). MSP was defined based on questions regarding body pain sites. Additionally, PPT and PPTo were assessed using algometer measurements. Mann-Whitney U-test and Tobit regression models were used to analyse associations between TMD sub-diagnoses, MSP, PPT and PPTo, stratified by sex. Further models were adjusted with anxiety and depressive symptoms, which were assessed using Hopkins Symptom Checklist-25 (HSCL-25) and two-way interaction terms., Results: Among females, lower PPT and PPTo were associated with myalgia and arthralgia. Among males, lower PPT and PPTo were associated with MSP-linked TMD. Tobit regression analysis showed significantly lower PPT and PPTo values in the myalgia and arthralgia subgroups among female TMD subjects. Among females, disc displacement with reduction had an inverse association with PPT and PPTo. Among males, lower PPTo was associated with degenerative joint disease and MSP-linked TMD., Conclusions: The pain regulatory mechanisms behind TMD act differently between the genders as local TMD among females and MSP-linked TMD among males were associated with pain sensitivity., Significance: The study shows that there are differences in the associations of painful TMD with pressure pain tolerance, pressure pain sensitivity and MSP between male and female subjects., (© 2021 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC ®.)

Aim: The aims were to describe the development of a modified national online OSCE during COVID-19 and assess related student feedback., Material and Methods: The modified online OSCE comprising of eight question entities was organised simultaneously in all four dental institutes of Finland using the Moodle virtual learning environment. All fourth-year students (n = 179) attended the examination online at home. Student feedback was collected via an anonymous questionnaire with multiple-choice questions and open-ended questions concerning attitudes towards the modified online OSCE, as well as content and usability of the question entities in the examination. Means and standard deviations were calculated for multiple-choice questions. Content analysis was used for open-ended questions., Results: Of 179 students, 119 (66%) consented to the study. Students experienced they had received adequate information (mean 3.8; SD 1.2), had a positive attitude before the examination (4.0; 1.0) and found the practice test useful (3.7; 1.1) (range 1-5). Technical implementation (2.7; 0.7) and the difficulty of the questions (2.9; 0.6) (range 1-4) were found to be good. The teaching students received during their studies was sufficient (3.2; 0.5) (range 1-4). Content (mean 3.2; 0.4) and usability (2.9; 0.4) of the question entities were good (range 1-4). The themes arising from open-ended questions were importance and practicality of the topic (in questions) in relation to the work of a dentist and gratitude for the rapid conversion of the OSCE into an online examination despite COVID-19. The themes arising from negative experiences included difficulties in completing the examination within the time allocated, and dissatisfaction with the model answers provided after the examination., Conclusion: The positive student feedback towards the modified online OSCE encourages including an online examination to complement the traditional OSCE., (© 2020 The Authors. European Journal of Dental Education published by John Wiley & Sons Ltd.)

Objective: The aim of the pilot study was to investigate the association of pain-related disability with the outcome of conservative treatment of temporomandibular disorders (TMD) and with depressive and non-specific physical symptoms among TMD pain patients utilizing Graded Chronic Pain Scale 1.0 (GCPS1.0) as a screening instrument., Material and Methods: The study included 80 adult patients who were referred to the Oral and Maxillofacial Department, Oulu University Hospital, Finland, due to TMD pain. At baseline, pain-related disability was assessed by using the GCPS1.0 according to the Research Diagnostic Criteria for TMD (RDC/TMD), and the patients were categorized into three TMD subtypes, 1-3. Patients were given conservative TMD treatment. At follow-up visits (1, 3, 6, and 12 months), patients evaluated the pain intensity on an NRS and described the treatment outcome and the severity of the TMD symptoms on a numerical scale., Results and Conclusions: Patients with TMD subtype 3 (moderate/severe disability) had the highest NRS scores and described their symptoms as most severe at each time point, statistically significantly so at 1-month and 6-month follow-up ( p  < .05). The highest proportion of depressive symptoms was found in TMD subtype 3 ( p  < .05). The current pilot study showed that moderate/severe TMD-related disability, based on the GCPS 1.0 as a screening tool, may be linked with poor treatment outcome and depressive symptoms. Studies with larger samples are needed to confirm the results.

Objective: This study aimed to evaluate the association between temporomandibular disorders (TMD) and oral health-related quality of life (OHRQoL) in an adult population., Methods: The data included 1,768 adults 46 years of age in the Northern Finland Birth Cohort 1966 (NFBC1966) study. The symptoms, signs and diagnoses of TMD were assessed using a modified protocol of the Diagnostic Criteria for TMD (DC/TMD) and validated questionnaires. OHRQoL was measured using the Oral Health Impact Profile (OHIP-14). Associations of TMD and OHRQoL were evaluated with χ 2 -test and Fisher's exact test., Results: In females, pain-related TMD signs and diagnoses associated significantly with prevalence of OHIP total and all dimensions, whereas in joint-related TMD, psychological dimensions showed the strongest association. Males with pain- or joint-related TMD, the most impaired dimension was physical pain., Conclusion: Pain-related TMD seems to associate more strongly with lower OHRQoL than joint-related TMD especially in females.

Objective: To investigate the prevalence of self-reported bruxism and its association with temporomandibular disorders (TMD). The hypothesis of the study was that self-reported bruxism is associated with TMD., Methods: The data were gathered from 1962 subjects who participated in a field study in 2012-2013, including a questionnaire concerning bruxism and TMD symptoms as well as clinical sub-diagnoses of TMD using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Statistical method was chi-square test. Bonferroni correction was made, and a p -value of <0.003 was considered as significant., Results: The prevalence of self-reported bruxism was 39.6%: 34.0% in men and 44.5% in women. Those who reported sleep bruxism (SB) or awake bruxism (AB) had significantly more pain-related TMD symptoms and signs compared to those not reporting bruxism., Conclusion: The prevalence of self-reported bruxism is high among middle-aged adults and is associated with TMD pain-related symptoms and signs, as well as TMD diagnoses.

Objective: Hormonal factors have been suggested to contribute to female dominance among subjects with temporomandibular disorders (TMD). Aim of the study was to examine the association of climacteric status with TMD amongst female participants in the Northern Finland Birth Cohort (NFBC) 1966 at 46 years of age., Material and Methods: Among female subjects in NFBC1966, climacteric status was determined based on menstrual anamnesis and measurement of blood follicle-stimulating hormone (FSH) levels. Women with FSH > 25 IU/L and amenorrhoea > 4 months were defined as climacteric (case group, n =  71); women not diagnosed as climacteric were defined as preclimacteric (control group, n =  656). Differences between cases and controls were evaluated on self-reported TMD pain, clinical TMD signs and TMD diagnoses using modified Diagnostic Criteria for TMD (DC/TMD) protocol. Crosstabulation and logistic regression models were used to analyse differences between cases and controls., Results: Compared to preclimacteric women, climacteric women had significantly more often pain on palpation in temporomandibular joints (TMJs) (OR = 2.64, 95% CI 1.12-6.21, p=  .026) and more crepitus in TMJs (OR = 2.92, 95% CI 1.13-7.56, p=  .027). Degenerative joint disease diagnoses were more common in climacteric than preclimacteric women (OR = 2.27, 95% CI 1.05-4.91, p=  .037). Differences were statistically significant after adjusting for confounding factors (body mass index (BMI), smoking, parity). No statistically significant differences in self-reported TMD pain were noted between groups., Conclusion: Among females at the age of 46 years, climacterium seems associated with TMD by increasing pain on palpation in TMJs, subjective symptoms, and clinical signs indicating degenerative changes in TMJs when using DC/TMD.

Objective: The study aimed to investigate the association of sleep bruxism (SB) and awake bruxism (AB) with health-related factors., Methods: Data on bruxism and diagnosed diseases, use of psychoactive substances and regular identified psychoactive drugs were collected from 1,962 subjects in the Northern Finland Birth Cohort 1966 through a questionnaire. The associations were analyzed using chi-square tests and binary regression models, adjusting for gender and education, and for anxiety/depression symptoms., Results: Migraine and gastric/duodenal disorders, use of serotonergic antidepressants and a high number of psychoactive drugs associated significantly with AB and SB. Gastrointestinal diseases associated with SB. Poor general health and hand eczema associated with AB. Based on the multivariate model, depression/anxiety symptoms seemed to mediate the associations of bruxism with depression, hand eczema, self-reported gastric/duodenal disorders and the number of identified drugs., Conclusion: Several diseases, depression/anxiety symptoms and psychoactive medications were associated with SB and AB, the associations being stronger with AB than SB.

Introduction: For over the last 20 years, approximately 70% of working dentists in Finland have been women. However, there is internal division of the profession along gender lines. Female dentists work more often in the public sector and male dentists in the private sector. The aim of this study was to investigate the gender differences in young dentists' early career choices, specialization plans, values and perceptions of professional identity., Materials and Methods: The data were taken from a national e-mail questionnaire study called "Young Dentist," which was sent to 458 dentists who had received their licence to practise dentistry in 2014-2016 from all four universities with dental curricula in Finland. A total of 52% young dentists (n = 238) answered the questionnaire., Results and Discussion: The results indicated that whereas female dentists were more likely to perceive themselves as comforters, social workers and health promoters, male dentists tended to perceive themselves as technicians. These professional identities were interrelated with early-stage career choices in which female dentists worked more often in the public than in the private sector when compared to male dentists. There were also clear gender differences in the importance of values and the specialization plans of the young dentists., Conclusion: Young dentists in Finland make career choices and develop professional identity in accordance with the attributes traditionally associated with cultural ideals related to femininity and masculinity., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To examine the prevalence of sagittal relationships, asymmetries and midline shift, and their associations with temporomandibular disorders (TMD) in the Northern Finland Birth Cohort 1966 (NFBC1966)., Materials and Methods: 1845 subjects participated in a clinical examination at the age of 46. Occlusal measurements were performed using 3D models. Symptoms of TMD were screened using validated questions, and signs and diagnoses of TMD were assessed using a modified protocol of the Diagnostic Criteria for TMD (DC/TMD) and questionnaires. Associations between variables of occlusion and TMD were evaluated with χ 2 -test and Fisher's exact test and using logistic regression analyses, adjusted for self-reported general health, mental health, bruxism, and rheumatoid arthritis., Results: The most common sagittal relationships were Class I and normal canine relationship. Half-cusp Class II and post-normal canine relationship were more frequent in females, and Class III and pre-normal canine relationship in males. Deviations from normal cuspid or molar relationships showed a weak but statistically significant association with TMD, especially in females. Half-cusp Class II and Class II relationships were more frequent in relation to joint-related TMD signs and diagnoses while missing canines were associated with pain-related TMD diagnoses., Conclusions: The present study findings gave some indications that canine relationships are associated with pain-related TMD, whereas Angle II sagittal occlusal relations may associate with joint-related TMD. Occlusal characteristics should therefore be taken into account as one possible associating factor in subjects with TMD.

Objective: The aim was to evaluate the distribution of congenitally missing teeth and the treatment provided for congenitally missing lower second premolars in an eleven-year cohort of patients referred to a publicly funded source of specialist care., Material and Methods: This was a retrospective, register-based cohort study. Search for patients referred to a publicly funded source of specialist care based on ICD10 diagnosis code K00.00 (partial anodontia) and treatment codes EBA00, EBA05, EBA10, EBA12, EBB10 and EBB20 during the period 1.1.2009-27.10.2019 yielded 232 patients (151 females, 81 males), of whom 218, born in 1941-2009, were eligible. Data collected from medical files were presented in the form of descriptive statistics and analysed using Fisher's exact test., Results: The 218 subjects possessed 876 congenitally missing teeth (males 307, females 569) (third molars excluded). The most common missing teeth were upper second premolars and lateral incisors, and lower second premolars and central incisors. No difference in laterality was found. Statistically significant associations were found between the choice of treatment and both the patient's age at referral and the patient's year of birth. Most common treatment for adult patients (age 18-56 years) was placement of an implant (67%), while autotransplantation (11%) was the preferred option for children at the mixed dentition stage (age 9-15 years)., Conclusions: The congenitally missing teeth most commonly involved in referrals of patients to publicly funded specialist care were lower second premolars. The most frequent treatment was insertion of an implant for adults and autotransplantation at the mixed dentition stage.

Aims: Efforts to harmonise dental education in Europe have been put into action by the Association for Dental Education in Europe (ADEE). The aim of the study was to explore graduating dentists' perceptions about their professional readiness for clinical work in Finland and Lithuania., Materials and Methods: The survey targeted fifth-year dental students at the University of Oulu and the University of Turku in Finland, and at the Lithuanian University of Health Sciences, Kaunas, Lithuania (Lithuanian and international students) in 2016-2017. The competences were evaluated in the questionnaire in 21 dental procedures based on ADEE competences by options: "I'd manage well," "I'd need more training" or "It would not quite succeed." The option "I'd manage well" was chosen in the analyses., Results: Students felt that they were most competent in producing and maintaining accurate patient records (91.9%), implementing sterilisation and hygiene in dental practice (91.3%) and working with other members of dental team and health profession (90.0%). The largest differences between Finnish and Lithuanian students were in designing and adjusting occlusal splints (87.0% vs. 14.3%) and in undertaking subgingival scaling (95.7% vs. 57.1%). The biggest differences between Lithuanian and international students were in identifying (and treating) abnormal and anxiety-related patient (73.1% vs. 25.5%) and implementing tobacco cessation (65.3% vs. 31.9%)., Conclusions: The graduating dental students in Finland and Lithuania manage well in most of the clinical procedures based on the ADEE competences. The students were most confident when dealing with tasks that are common in dental practice., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The aim of this study was to evaluate the association of psychosocial distress and widespread pain with self-reported symptoms of temporomandibular disorders (TMD) and bruxism, in two cross-sectional surveys in 2012 and 2016, and whether there are temporal changes in the magnitude of associations., Materials and Methods: The data were gathered from Finnish university students in 2012 and 2016. TMD symptoms were assessed with three validated questions and bruxism with one frequently used question. Psychosocial distress was assessed with the General Health Questionnaire-12 (GHQ-12), and widespread pain with questions of pain in the extremities, the neck or upper back, and lower back. The associations of GHQ-12, widespread pain and background variables with TMD symptoms and bruxism were analyzed with chi-square tests, t-test and binary logistic regression models stratified by gender, and adjusted for age-group, self-reported general health/wellbeing and presence of widespread pain., Results: Higher GHQ-12 score and presence of widespread pain were significantly associated with TMD symptoms in both genders at both time points. The association of higher GHQ-12 score with sleep bruxism and awake bruxism were inconsistent. In the adjusted model higher GHQ-12 score and widespread pain were significantly related to TMD pain symptoms in both genders at both time points, and to bruxism in 2012. Between the two time points a greater variability in these associations was seen in men than in women., Conclusions: Psychological distress and widespread pain are significant determinants in perceived TMD pain and bruxism among students. No significant temporal alterations were observed., (© 2021 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

Objectives: The aim of this retrospective data collection study was to determine the effect size of dry mouth on the survival of restorations and teeth., Methods: The data were collected from the electronic patient files of City of Oulu Public Dental Services (Finland). Study population consisted of 71 dry mouth patients and 142 control patients. The survival of 3208 restorations were analyzed using Kaplan-Meier survival curves and multivariate Cox regression analysis with shared frailty for patients. Separate analyses were performed for the survival of the teeth., Results: The hazard ratio of restorations in dry mouth patients was 2.08 (95% CI: 1.65-2.63) compared to the control patients. For the dry mouth patients, the fixed prosthetic crowns outlasted composite fillings of all sizes, but the difference increased concomitantly with the filling size. The dry mouth patients had hazard ratio of 1.98 (95% CI: 1.02-3.82) for tooth extractions compared to the control patients. The teeth with fixed prosthetic crowns outlasted the teeth with direct restorative materials., Conclusions: The survival time of restorations and teeth are severely shortened in patients with dry mouth. Especially the survival time of the large composites is short in dry mouth patients whereas fixed prosthetic crowns have acceptable survival time also in dry mouth patients., Clinical Significance: When informing a dry mouth patient on the expected survival of a restoration or tooth, one should take into account that dry mouth patients´ restorations and teeth have severely shortened survival time., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

PURPOSE: The aim of this clinical retrospective study was to evaluate the survival and success of single metal-ceramic crowns after 20 years. The biologic and technical complications as well as patient satisfaction were recorded. MATERIALS AND METHODS: Fifty patients treated with 100 single metal-ceramic crowns attended the clinical 20-year follow-up examination. The mean follow-up time was 18.8 years (17.5 to 20.5 years). RESULTS: Twenty-one teeth with single crowns were extracted because of root fractures or esthetic or periodontal reasons. Ninety-seven percent of the subjects had no complaints about the esthetics of the crowns. The most common clinical findings were supragingival crown margins caused by gingival recessions, gingival bleeding on probing, and occlusal wear in opposing teeth. The success of the crowns after 20 years was 75%, and the survival was 78%. CONCLUSION: In the 20-year follow-up of single metal-ceramic crowns, there were few biologic and technical complications, and patients were satisfied with the crowns. Crown removal was in most cases the result of root fractures in single crowns with endodontic posts. [ABSTRACT FROM AUTHOR]

Aims: To compare the suitability of Graded Chronic Pain Scale (GCPS) pain intensity and interference assessments (GCPS version 1.0 vs 2.0) for the biopsychosocial screening and subtyping of Finnish tertiary care referral patients with TMD pain., Methods: Altogether, 197 TMD pain patients participated in this study. All patients received Axis II specialist-level psychosocial questionnaires from the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD-FIN) and Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD-FIN), as well as questionnaires for the assessment of additional pain-related, biopsychosocial, and treatment-related variables. Clinical examinations were performed according to the DC/TMD Axis I protocol. The patients were categorized into TMD subtypes 1, 2, and 3 (GCPS I and II-low; II-high; and III and IV, respectively) based on their biopsychosocial profiles according to GCPS versions 1.0 and 2.0., Results: The distribution of TMD pain patients into TMD subtypes was similar according to the GCPS 1.0 compared to the GCPS 2.0. Over 50% of the patients were moderately (TMD subtype 2) or severely (TMD subtype 3) compromised. Patients in subtype 3 experienced biopsychosocial symptoms and reported previous health care visits significantly more often than patients in subtypes 1 and 2. Patients in subtype 2 reported intermediate biopsychosocial burden compared to subtypes 1 and 3., Conclusion: TMD pain patients differ in their biopsychosocial profiles, and, similarly to the GCPS 1.0, the GCPS 2.0 is a suitable instrument for categorizing TMD tertiary care pain patients into three biopsychosocially relevant TMD subtypes. The GCPS 2.0 can be regarded as a suitable initial screening tool for adjunct personalized or comprehensive multidisciplinary assessment.

Purpose: To assess wear, fa+gue, and fracture resistance of different CAD/CAM onlays milled from monolithic zirconia (ZR), hybrid ceramic (EN), and lithium disilicate (LS) when used as abutments for removable par+al denture frameworks fabricated from acetal resin (AR) or cobalt-chromium (Co-Cr). Materials and Methods: Standard onlays and RPD framework were designed and milled using CAD/CAM. Onlays were cemented with resin cement to iden+cal teeth models. The RPD's occlusal rest surface and the ceramic onlays' rest seats were both 3D scanned before and aPer 750,000 mechanical load cycles (50 N) and 8,000 thermal cycles (5° to 55°C) in a chewing simulator. The volumetric loss was measured using 3D-image processing soPware, and the failure of the samples was detected using a stereomicroscope. The fracture resistance was tested by loading to failure in a universal tes+ng machine. The fa+gue failure results were analyzed with Fisher exact probability test, and the wear and fracture resistance data were analyzed using twoway ANOVA and Bonferroni post-hoc test (P < .05). Results: A significant difference (P < .05) was found between the tested experimental groups in wear, fa+gue, and fracture resistance. Zr/Co-Cr combina+ons exhibited the least wear and the highest fa+gue and fracture resistance (P < .05), while the highest wear and least fa+gue and fracture resistance were recorded for the EN/AR group (P < .05). Conclusions: Zr onlays demonstrated a conserva+ve treatment op+on with superior mechanical behavior when used as an onlay abutment, regardless of the RPD framework material used. The AR framework is not recommended in the posterior region for removable par+al dentures. [ABSTRACT FROM AUTHOR]