Fracture Resistance of Posterior Tooth-Supported Cantilever Fixed Dental Prostheses of Different Zirconia Generations and Framework Thicknesses: An In Vitro Study.

The rehabilitation of free-end situations is a frequent indication in prosthetic dentistry. Cantilever fixed dental prostheses (cFDPs) made of 1st and 2nd generation zirconia are one treatment option. Due to a unique gradient technology, combinations of different zirconium dioxide generations are thus feasible in one restoration. However, data about these materials are rare. The purpose of this study was therefore to investigate the fracture resistance and fracture modes of tooth-supported cFDPs fabricated from different zirconia materials (gradient technology) and different framework thicknesses. A total of 40 cFDPs were fabricated using the CAD/CAM approach and belonged to five test groups. The different groups differed in the yttria content, the proportion of the tetragonal/cubic phases, or in wall thickness (0.7 mm or 1 mm). After completion, the cFDPs were subjected to thermal cycling and chewing simulation (1.2 × 106 load cycles, 108 N load). Afterwards, cFDPs were statically loaded until fracture in a universal testing machine. A non-parametric ANOVA was compiled to determine the possible effects of group membership on fracture resistance. In addition, post-hoc Tukey tests were used for bivariate comparisons. The mean fracture loads under axial load application ranged from 288 to 577 N. ANOVA detected a significant impact of the used material on the fracture resistances (p < 0.001). Therefore, the use of cFDPs fabricated by gradient technology zirconia may not be unreservedly recommended for clinical use, whereas cFPDs made from 3Y-TZP exhibit fracture resistance above possible masticatory loads in the posterior region.

A German version of the Oral Impacts of Daily Performances-reliability and validity.

OBJECTIVE: The Oral Impact of Daily Performances (OIDP) is a dental patient-reported outcome measure (dPROM) for the estimation of oral health-related quality of life (OHRQoL) and takes the frequency as well as the severity of problems into account; however, it is not available in German language. The aim of this study was, therefore, to evaluate the reliability and validity of the German version of the OIDP in patients of a private practice. MATERIAL AND METHODS: Translation of the original OIDP version was performed by a forward-backward process. Reliability was evaluated in terms of construct stability (test-retest) for the single items and the sum scores. The responsiveness to change in oral health status was assessed by pre- and post-treatment comparison, in addition. Validity was assessed as convergent validity in comparison with other dPROMs (OHIP-14; GOHAI) and objective dental findings. RESULTS: A total of 330 patients participated in this study (mean age: 42.0 (18.0)). The OHRQoL of the participants was relatively high (OIDP score 4.3 (SD 14.3), OHIP score 4.8 (SD 5.3), GOHAI score 54.2 (SD 5.4)). A moderate construct stability for the total OIDP-score (ICC 0.686) was found whilst reliability for the single items varied between 0.179 (social contact) to 0.559 (showing teeth). Significant correlations were found for OIDP and OHIP (p < 0.001; r = 0.361) and OIDP and GOHAI (p < 0.001; r = - 0.391) indicating moderate validity with a tendency to even stronger correlations for OIDP-s and OIDP-f (r ≥ 0.500). CONCLUSIONS: The German version of the OIDP demonstrated sufficient reliability and validity. OIDP's general performance should be interpreted cautiously as the outcome was detected in a specifically healthy population. CLINICAL RELEVANCE: The OIDP is yet the only dPROM that evaluates both severity as well as frequency which makes validation interesting regarding specific target populations.

The Impact of the SARS-CoV-2 Pandemic on Stress and Anxiety of Dental Students.

OBJECTIVES: To investigate the impact of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic on stress and anxiety of preclinical and clinical dental students. MATERIALS AND METHODS: Dental students (participants) in their clinical course (CC; n = 64) or preclinical course (PCC; n = 53) were included in the study. The subjective perceived levels of stress and anxiety were evaluated using the Dental Environment Stress (DES) questionnaire and the Depression, Anxiety and Stress Scales (DASS) questionnaire. Cortisol levels were measured in saliva samples collected from participants. Knowledge of the pandemic was evaluated using a 100-mm visual analog scale. All data were collected twice: once during the university holidays and once during term time. STATISTICAL ANALYSIS: Results from DES, DASS, and salivary cortisol tests were compared between baseline and follow-up using descriptive and bivariate statistics. Multivariate linear regression models were computed with DES, DASS, and cortisol values as dependent variables to analyze possible influencing factors. RESULTS: Participants showed medium levels of stress and anxiety at baseline and follow-up. The DASS score in the "anxiety" subdomain was significantly higher in the PCC group than in the CC group at baseline (p < 0.001) and increased during term time. DASS scores in the "stress" subdomain also increased during term time. However, both subdomain scores were lower than the cutoff value for a psychological disorder. The mean total DES scores were 615.9 ± 97.7 in the CC group and 580.40 ± 98.9 in the PCC group. These scores indicated medium stress levels and were not significantly different between the groups, nor did they change during the study period. Mean saliva cortisol levels were higher in the CC group (9.2 ± 5.2) than in the PCC group (4.9 ± 2.2) at baseline (p < 0.001) but converged by follow-up. Multivariate regression models showed that intraindividual perception of stress at baseline was consistently the most important aspect for changes in stress and anxiety levels during term time. The SARS-CoV-2 pandemic affected stress and anxiety levels in some participants, but this was not ubiquitous. CONCLUSION: Intraindividual differences in stress perception seem to be more relevant than course affiliation (preclinical or clinical) or the SARS-CoV-2 pandemic to stress and anxiety levels in dental students.

Adapting the German version of the dental environment stress questionnaire.

AIMS: To develop a German version of the Dental Environment Stress (DES) questionnaire, and to evaluate its reliability and validity. METHODS: The original English DES questionnaire was translated into German using a forward-backward translation process. To evaluate construct stability, a subgroup of dental students (n = 43) completed the DES twice (interval: 1 week). To evaluate how the DES responds to anticipated changes in stress, all dental students' (n = 64) DES scores and saliva cortisol levels administered from a clinical study were compared between holiday and term time. Furthermore, the Depression, Anxiety and Stress Scale (DASS) and a stress self-assessment were used to determine the validity of the DES. Reliability analyses were calculated using Kendall's tau correlations. To estimate reliability strength, correlation coefficients and intraclass correlations (ICCs) were used. RESULTS: Regarding construct stability, 24 of 25 DES items had at least moderate correlations, and most items showed strong correlations. Correlations for the seven subdomains were good (range: 0.778-1.000). The same was true for the total DES score (ICC: 0.944). Correlations for response to term-time stress were weaker and more varied. Validity analyses revealed fair correlations between the DES and students' self-assessment (Pearson's r = .592) and DASS score (Pearson's r = .392), suggesting satisfactory validity. Stress levels were quite similar between baseline and follow-up. CONCLUSION: The German DES is a reliable tool for evaluating stress in dental students. Because it can be used to identify individual stressors in various categories, it might enable the detection of specific stress situations in educational situations and facilitate solutions (adjustment of curricula, tailored consulting services).

Laboratory and clinical reliability of two spectrophotometers.

OBJECTIVE: To evaluate the repeatability, interexaminer, and interdevice reliability of two clinically applicable spectrophotometers under laboratory and clinical conditions. MATERIAL AND METHODS: For the in vitro part of the study, measurements were performed by the use of Vita Easyshade Advance 4.0 (ES-A) and the Easyshade V (ES-V) at identical positions on different shade tabs (3D-Master; Vita Zahnfabrik, Bad Säckingen, Germany). To test repeatability, one shade tab was measured 50 times by one operator. To determine interrater and interdevice agreement, two operators used both devices to perform 10 measurements on five different shade tabs. Clinical interdevice and interexaminer reliability was checked with a positioning jig used (15 participants). Measurement accuracy of both devices was evaluated for the recommended color of shade tabs. RESULTS: Repeatability of results from both Easyshades was excellent for all color components (maximum deviation between measurements was ≤0.1 units). Interrater agreement was also perfect (intraclass correlation, ICC = 1.000). Interdevice agreement was lower, but still good (ICC ≥ 0.834). In the clinical environment, interrater and interdevice agreements were similar (ICC > 0.964 and ICC > 0.873). Accuracy was satisfactory for both devices, with both observers in full agreement for nearly 80% of ratings. CONCLUSIONS: Both Easyshades produced reliable and accurate measurements and can therefore be recommended for clinical determination of tooth color. CLINICAL SIGNIFICANCE: The outcome of this study might help clinicians estimate the performance of a new digital shade determination device.

Survival and success of tooth-implant-supported and solely implant-supported double-crown-retained overdentures: A prospective study over a period of up to 11 years.

OBJECTIVES: To investigate the long-term performance, over a period of up to 11 years, of tooth-implant-supported and solely implant-supported double-crown-retained overdentures (DCRDs) for complete restoration of the jaw. MATERIALS AND METHODS: Between 2002 and 2015, patients were consecutively enrolled in the study at Heidelberg University Hospital's Department of Prosthodontics. Scheduled and unscheduled visits were both documented on standardized forms. Kaplan-Meier curves were used to evaluate survival and success of the DCRDs. Mixed effects Cox regression was used to identify the potential effects of age, sex, jaw, location of implants, and the number of abutment teeth on the success of the DCRDs. RESULTS: One hundred and thirty-nine DCRDs were placed in 126 participants (mean age: 65.6 ± 9.1 years; 76 [60.3%] men). The mean follow-up period was 4.2 years. Fifty-three (38%) DCRDs were solely implant-supported (213 implants) and 86 (62%) were tooth-implant-supported (239 teeth and 199 implants). Cumulative five-year survival was 96.2% in the implant-supported group and 97.7% in the tooth-implant-supported group. Simultaneous consideration of failures and severe complications revealed cumulative five-year success of 88.2% for implant-supported DCRDs and 81.9% for tooth-implant-supported DCRDs, with no significant difference between the two types of restoration. Cox regression analysis revealed a greater risk of major complications (hazard ratio: 4.87, p = .04) for maxillary DCRDs than for mandibular DCRDs. CONCLUSIONS: Although the study design has limitations, the results show that tooth-implant-supported and solely implant-supported DCRDs are both recommendable treatment options. After a mean follow-up of 4.2 years, survival and success were high. However, minor complications were common and required much aftercare. CLINICAL TRIAL REGISTRATION: This study started in 2005 and was approved by the local review board of the University of Heidelberg. In 2005, clinical trial registration was not yet common. For this reason, the study was not registered.

Maxillary implant overdentures on two or four implants. A prospective randomized cross-over clinical trial of implant and denture success and survival.

OBJECTIVES: To determine implant survival and success of four conventionally but initially asynchronously loaded implants in implant-supported overdentures for the edentulous maxilla, in participants with opposing mandibular two-implant overdentures. MATERIAL AND METHODS: Twenty-six participants received four implants in the region of the maxillary canines and molars. After healing, 24 of these participants (mean age: 68.3 years) were randomly allocated to one of two treatment groups, and the adapted overdenture was attached to two unsplinted cylindrical attachments. The other two matrixes remained unattached to the implants for 3 months. After this period, the other two implants were loaded for 3 months (cross-over design). Then, all four implants were loaded for another 3 months. Kaplan-Meier curves were used to evaluate survival and success of implants and dentures. RESULTS: During the active prosthetic study phase, three participants lost one implant. Two participants lost three implants during the recall period. Implant survival after loading was 93.8% after a mean observation period of 3.1 years. Denture survival was 100%, but denture success was 95.8%, due to major prosthetic complications. Most participants preferred four implants to two. CONCLUSIONS: Within the limitations of the study, it can be concluded that maxillary implant overdentures on two or four implants are both recommendable treatment options. Two posterior implants are not superior to two anterior implants under overdentures retained by unsplinted cylindrical attachments. Implant and prosthetic complications and aftercare measures are common but are mostly easy to handle. However, 23 of the 24 participants preferred the 4-implant maxillary overdenture.

How Do Changes in Oral Health and Chewing Efficiency Affect the Changes of Oral-Health-Related Quality of Life of Nursing-Home Residents in the Short Term?

OBJECTIVE: To evaluate how changes in oral health and chewing efficiency affect the changes in oral-health-related quality of life (OHRQoL) of nursing-home residents over six months. METHODS: The study was conducted in nine nursing homes. Sociodemographic and general data were collected for all eligible individuals (n = 150). Of these, 114 participants (mean age 82.0 [± 9.5] years, 77.2% women) were available for the following tests at baseline and six months later: a comprehensive examination of dental and general health, a two-colour mixing-ability test (to assess chewing efficiency), the Geriatric Oral Health Assessment Index (GOHAI; to evaluate the OHRQoL), and the Mini Mental State Examination (MMSE; to diagnose the presence and severity of dementia). Univariate and multivariate linear regression models were compiled to analyse possible factors affecting OHRQoL. RESULTS: For the final analysis, 108 participants were available. For the study cohort as a whole, a decrease in the number of functional occluding pairs (C: 0.195; p = 0.034) and an increase in dental-treatment needs (C: -1.968; p = 0.056) had the greatest negative effects on OHRQoL as expressed by the GOHAI score. For denture wearers, a deterioration of denture condition (C: -2.946; p = 0.003) was the most important predictor for a decline in OHRQoL. CONCLUSION: A short-term decline in oral health and function affects the OHRQoL of nursing-home residents. The most important dental variables in this regard are the number of functional occluding pairs and dental and denture-related treatment needs.

[Dental treatment in old age-When and what is indicated?] / Zahnärztliche Therapie im Alter ­ Wann ist was indiziert?

In the past few years the oral health of seniors has improved and more seniors retain their natural teeth until old age; however, the prevalence of oral diseases among seniors is still very high and a serious problem. Good oral health is, however, relevant for seniors as it influences the chewing function, the nutritional status and general satisfaction. In addition, diseases of the oral cavity show interactions with general health. The current article therefore provides an evidence-based overview of the oral health of seniors and highlights important relationships (nutritional status, oral health-related quality of life, general health). It also gives advice on when dental treatment may be indicated. Furthermore, instruments for assessing oral health, chewing function and oral health-related quality of life are presented and explained.

Which factors influence the oral health of nursing-home residents with cognitive and motor impairments?

BACKGROUND: There is limited information available about the oral and denture hygiene and oral health of nursing-home residents with cognitive and motor impairments. AIMS: The purpose of this study was to identify factors influencing the oral and denture hygiene and oral health of nursing-home residents with cognitive and motor impairments. METHODS: The study was performed in nine nursing-homes in Germany. Sociodemographic and general data were collected for all participants (n = 150). The Clinical Dementia Rating (CDR) was used to identify the presence of dementia, and the Apraxia Screening Test (AST) was used to identify motor impairment. A comprehensive dental examination was also performed. This included the documentation of dental and denture status and the number of decayed, missing and filled teeth (DMFT). In addition, dental and denture hygiene were assessed using the Plaque Index (PI) and the Denture Hygiene Index (DHI). Univariate and multivariate regression models were used to analyse possible factors affecting the dependent target variables. RESULTS: In multivariate regression analysis, the factors that most strongly influenced greater PI were a lower number of medications taken (p = 0.018), poorer general health (p = 0.013) and the presence of dementia (p < 0.010). A more advanced age (p = 0.036) and longer nursing-home stay (p = 0.048) had a negative effect on the DHI. Furthermore, gender (p = 0.037, in favour of women), poorer general health (p = 0.003), presence of dementia (p = 0.003), and the absence of natural teeth (p = 0.028) influenced poorer oral health. The factors most strongly influenced greater number of missing teeth were a more advanced age (p = 0.021) and longer nursing-home stay (p = 0.015). In terms of fewer filled teeth, a shorter nursing-home stay (p = 0.002) was the factor most strongly influenced this. CONCLUSIONS: Poorer general health and the presence of apraxia and cognitive impairment are the main determinants for poorer oral hygiene and oral health among nursing-home residents. A longer nursing-home stay also seems to be relevant for oral health and denture hygiene.