Influence of provisional cementation on the stability of adhesively bonded resin-based composite crowns.

PURPOSE: To investigate the influence of temporary cementation and subsequent bonding on the durability during in-vitro aging-simulation and fracture force of resin-based composite crowns. METHODS: Identical molar crowns (n=48, n=8 per group) were milled from resin-based composites and temporarily cemented and finally bonded to human molars. To simulate temporary application, crowns were cemented either with zinc-oxide-eugenol-cement (Tempbond) or with eugenol free zinc-oxide-cement (Tempbond NE). For a first simulation of a long-term provisional clinical application, thermal cycling, and mechanical loading (TCML 2 x 600 x 5°C-55°C, 2 minutes each cycle, distilled water, 240,000 cycles at 50N) was performed. After TCML all crowns were removed, cleaned, and luted either by using etch-and-rinse technique (Vococid, Futurabond U, Bifix QM) or a self-adhesive (Bifix SE) cementation system. A second thermal cycling and mechanical loading (TCML 2 x3,000 x 5°C/55°C, 2 minutes each cycle, distilled water, 1.2 x 106 at 50N) was accomplished to simulate 5 years of clinical application. To assess the survival of the crowns, the failure rates during TCML were documented. As controls, crowns were included without prior provisional cementation. After TCML all crowns were loaded to failure. Failure was categorized as fracture of the crown and partial loosening of the crown. RESULTS: All crowns survived both TCML procedures without any failures. The fracture values after TCML varied between 3,538.0 ± 1,041.2 N and 4,612.0 ± 801.5 N without significant (P= 0.146) differences between the individual groups. No correlation was found between fracture force and type of provisional cementation (zinc-oxide-eugenol vs. zinc-oxide: Pearson: -0.063/P= 0.672) or type of bonding (adhesive vs. self-adhesive: Pearson: -0.151/ P= 0.307). No different failure pattern was observed between the tested systems. CLINICAL SIGNIFICANCE: Regardless of the type of temporary cementation, there was no effect on the in-vitro performance or strength of the final permanently bonded crowns. Resin-based crowns might be bonded with adhesive or self-adhesive systems even after previous temporary cementation.

Effects of storage and toothbrush simulation on Martens hardness of CAD/CAM, hand-cast, thermoforming, and 3D-printed splint materials.

OBJECTIVES: To investigate Martens hardness parameters of splint materials after storage in liquids and toothbrush simulation. MATERIALS AND METHODS: Ten specimens per material and group were fabricated (hand-cast CAST, thermoformed TF, CAD/CAM-milled CAM, 3D-printed PS, PL, PK, PV), stored in air, water, coffee, red wine, and cleaning tablets and investigated after fabrication, 24 h, 2- and 4-week storage or toothbrushing. Martens hardness (HM), indentation hardness (HIT), indentation modulus (EIT), the elastic part of indentation work (ηIT), and indentation creep (CIT) were calculated (ISO 14577-1). STATISTICS: ANOVA, Bonferroni post hoc test, between-subjects effects, Pearson correlation (α = 0.05). RESULTS: HM varied between 30.8 N/mm2 for PS (water 4 weeks) and 164.0 N/mm2 for CAM (toothbrush). HIT values between 34.9 N/mm2 for PS (water 4 weeks) and 238.9 N/mm2 for CAM (toothbrush) were found. EIT varied between 4.3 kN/mm2 for CAM (toothbrush) and 1.8 kN/mm2 for PK (water 2 weeks). ηIT was found to vary between 16.9% for PS (water 4 weeks) and 42.8% for PL (toothbrush). CIT varied between 2.5% for PL (toothbrush) and 11.4% for PS (water 4 weeks). The highest impact was identified for the material (p ≤ 0.001). CONCLUSIONS: Storage and toothbrushing influenced Martens parameters. The properties of splints can be influenced by the choice of materials, based on different elastic and viscoelastic parameters. High HM and EIT and low CIT might be beneficial for splint applications. CLINICAL RELEVANCE: Martens parameters HM, EIT, and CIT might help to evaluate clinically relevant splint properties such as hardness, elasticity, and creep.

In vitro fatigue and fracture testing of temporary materials from different manufacturing processes in implant-supported anterior crowns.

OBJECTIVES: The aim of this study was to investigate the in vitro fatigue and fracture force of temporary implant-supported anterior crowns made of different materials with different abutment total occlusal convergence (TOC), with/without a screw channel, and with different types of fabrication. MATERIALS AND METHODS: One hundred ninety-two implant-supported crowns were manufactured (4° or 8° TOC; with/without screw channel) form 6 materials (n = 8; 2 × additive, 3 × subtractive, 1 × automix; reference). Crowns were temporarily cemented, screw channels were closed (polytetrafluoroethylene, resin composite), and crowns were stored in water (37 °C; 10 days) before thermal cycling and mechanical loading (TCML). Fracture force was determined. STATISTICS: Kolmogorov-Smirnov, ANOVA; Bonferroni; Kaplan-Meier; log-rank; α = 0.05. RESULTS: Failure during TCML varied between 0 failures and total failure. Mean survival was between 1.8 × 105 and 4.8 × 105 cycles. The highest impact on survival presented the material (η2 = 0.072, p < .001). Fracture forces varied between 265.7 and 628.6 N. The highest impact on force was found for the material (η2 = 0.084, p < .001). CONCLUSION: Additively and subtractively manufactured crowns provided similar or higher survival rates and fracture forces compared to automix crowns. The choice of material is decisive for the survival and fracture force. The fabrication is not crucial. A smaller TOC led to higher fracture force. Manually inserted screw channels had negative effects on fatigue testing. CLINICAL RELEVANCE: The highest stability has been shown for crowns with a low TOC, which are manufactured additively and subtractively. In automix-fabricated crowns, manually inserted screw channels have negative effects.

Long-term survival of monolithic tooth-supported lithium disilicate crowns fabricated using a chairside approach: 15-year results.

OBJECTIVES: To investigate the clinical performance of chairside fabricated tooth-supported posterior single crowns from lithium disilicate ceramic. MATERIALS AND METHODS: Thirty-four crowns (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein) were inserted between 2006 and 2007 and again evaluated after 15 years. Survival and success rates were calculated according to Kaplan-Meier, and the quality of the crowns was evaluated by using modified United States Public Health (USPHS) criteria. RESULTS: Twenty-two crowns were available for recall; six patients were defined as dropouts. The mean observation period was 15.2 years (± 0.2). Six failures occurred (1 technical/5 biological) resulting in a survival rate of 80.1%. The success rate was 64.2%. The roughness of the crowns increased (p = 0.021) and the majority of adhesive gaps were discolored (p = 0.001) in comparison to baseline. The color, tooth, and crown integrity remained stable over the follow-up period (p ≥ 0.317). CONCLUSION: The fabrication of tooth-supported lithium disilicate crowns using a chairside approach yielded acceptable long-term survival and success rates. Due to discoloration, the long-term use of dual-cure self-adhesive resin cements might result in unpleasing esthetic results. CLINICAL RELEVANCE: The performance of posterior lithium disilicate single crowns revealed excellent to good clinical quality and an acceptable number of events after 15 years of clinical service.

Prevalence of temporomandibular disorders and bruxism in seniors.

BACKGROUND: Information on the prevalence of temporomandibular disorders (TMD) or possible/probable bruxism in seniors is heterogeneous and sparse. OBJECTIVES: To elucidate the prevalence of TMD and possible/probable bruxism in German adults aged 60 years and older. METHODS: Participants of the Interdisciplinary Longitudinal Study of Adult Development and Aging (ILSE) born between 1950-1952 (C1) and 1930-1932 (C2) were examined in 2014-2016 (fourth wave). The participants were surveyed and clinically examined by one calibrated examiner. Two questions of the Patient Health Questionnaire (PHQ) were utilised to evaluate self-reported bruxism. The clinical examination included signs of probable bruxism and the RDC/TMD examination protocol. RESULTS: Data from 191 participants were available. No RDC/TMD diagnosis was made in 83.2%. Of the participants, 15.2% received a single diagnosis and 1.6% multiple diagnoses that included disc displacements (9.4%) and degenerative joint diseases (8.9%). A total of 24.7% reported bruxism that included self-reported awake bruxism in 11.9% and sleep bruxism in 16.2%. Wear was clinically identified in 27.2% of the participants. No sex-related differences were observed. Significant differences were detected for probable bruxism between C1 (14.1%) and C2 (54.3%). CONCLUSION: In the German population aged 60 years and older, the prevalence of TMD is 16.8%. TMD is characterised by temporomandibular joint disorders, including disc displacements and degenerative joint disorders. Bruxism was observed in a quarter of the old population.

Digital Workflow in Oral Splint Manufacturing.

AIM: The digital workflow used to manufacture an adjusted oral splint will be demonstrated in a patient case. MATERIALS AND METHODS: A 25-year-old female patient presented for management of her bruxism. Therefore, an adjusted oral splint was manufactured. A computer-aided motion analysis of the patient was conducted (JMA Optic, Amann Girrbach) and full-arch scans of the maxilla and mandible, a biocopy of the maxilla with bite fork as well as buccal scans of the centric jaw relation (Primescan, Dentsply Sirona). The jaw relation was determined beforehand by ballistic closing on a chairside fabricated anterior jig. The digital construction of a Michigan splint took place in the laboratory. The design was nested and milled from a polymethyl methacrylate (PMMA)-containing blank (CLEARsplint Disc, Astron Dental Corporation). RESULT: The oral splint was inserted into the patient's mouth and checked to ensure a tensionfree fit. The static and dynamic contact relationship was checked. During the follow-up visit, the patient reported an improvement in tension in the masticatory muscles. CONCLUSION: The procedure described allows for an adjusted oral splint to be manufactured in a purely digital workflow.

HOW TO IDENTIFY SUBGROUPS IN LONGITUDINAL CLINICAL DATA: TREATMENT RESPONSE PATTERNS IN PATIENTS WITH A SHORTENED DENTAL ARCH.

BACKGROUND: When dental patients seek care, treatments are not always successful,that is patients' oral health problems are not always eliminated or substantially reduced. Identifying these patients (treatment non-responders) is essential for clinical decision-making. Group-based trajectory modeling (GBTM) is rarely used in dentistry, but a promising statistical technique to identify non-responders in particular and clinical distinct patient groups in general in longitudinal data sets. AIM: Using group-based trajectory modeling, this study aimed to demonstrate how to identify oral health-related quality of life (OHRQoL) treatment response patterns by the example of patients with a shortened dental arch (SDA). METHODS: This paper is a secondary data analysis of a randomized controlled clinical trial. In this trial SDA patients received partial removable dental prostheses replacing missing teeth up to the first molars (N = 79) either or the dental arch ended with the second premolar that was present or replaced by a cantilever fixed dental prosthesis (N = 71). Up to ten follow-up examinations (1-2, 6, 12, 24, 36, 48, 60, 96, 120, and 180 months post-treatment) continued for 15 years. The outcome OHRQoL was assessed with the 49-item Oral Health Impact Profile (OHIP). Exploratory GBTM was performed to identify treatment response patterns. RESULTS: Two response patterns could be identified - "responders" and "non-responders." Responders' OHRQoL improved substantially and stayed primarily stable over the 15 years. Non-responders' OHRQoL did not improve considerably over time or worsened. While the SDA treatments were not related to the 2 response patterns, higher levels of functional, pain-related, psychological impairment in particular, and severely impaired OHRQoL in general predicted a non-responding OHRQoL pattern after treatment. Supplementary, a 3 pattern approach has been evaluated. CONCLUSIONS: Clustering patients according to certain longitudinal characteristics after treatment is generally important, but specifically identifying treatment in non-responders is central. With the increasing availability of OHRQoL data in clinical research and regular patient care, GBTM has become a powerful tool to investigate which dental treatment works for which patients.

Utilization of dental services and health literacy by older seniors during the COVID-19 pandemic.

BACKGROUND: This study aimed to investigate the utilization of dental services by older seniors during the COVID-19 pandemic and to evaluate their ability of finding, understanding, and using information on COVID-19. METHODS: At the end of February 2021, a survey addressing demographic characteristics of the participants, (pain-associated) utilization of dental services, worries regarding a potential COVID-19 infection, the individual use of protective masks, and difficulties regarding the access to information on COVID-19 (by using the modified European Health Literacy Questionnaire [HLS-EU-Q16]) was developed. It was sent to all patients of the Dental Clinic of University of Leipzig who were either 75, 80, or 85 years old (n = 1228). Participation was voluntarily and anonymously; questionnaires had to be returned within six weeks, no reminders were sent. RESULTS: Of the 439 replies (response rate 35.7%), twelve were excluded from data extraction due to disinterest, dementia, or lack of age information. Of the older seniors, 81.5% (n = 348) had utilized at least one dental examination and 54.2% of the dentulous patients (n = 199) had attended at least one dental hygiene appointment within the past year. Up to 55.8% of all participants said it was "difficult" or "very difficult" to find, understand, and use information on COVID-19, especially when judging reliability of information presented in the media, which was especially true for seniors with assigned care levels presenting odds ratios up to 5.30. CONCLUSIONS: The investigation revealed a frequent utilization of dental services by older seniors during the COVID-19 pandemic. However, the older seniors encountered difficulties finding, using, and understanding information about COVID-19.

[Prevalence of temporomandibular disorders in seniors-Symptom-related analyses in younger and older seniors]. / Prävalenz kraniomandibulärer Dysfunktionen bei Senioren ­ symptombezogene Analysen bei jüngeren und älteren Senioren.

BACKGROUND: Temporomandibular disorders (TMD) are common in the general population even in old age. Information on the prevalence of TMD in older people is sparse. OBJECTIVE: To present prevalence values for symptoms and signs of TMD in old people according to the research diagnostic criteria for temporomandibular disorders (RDC/TMD). To compare prevalence values between the age groups of 60-74 years (younger seniors) and ≥ 75 years (older seniors). MATERIAL AND METHODS: Subjects of the interdisciplinary longitudinal study of adult development (ILSE), a representative sample of old people in Germany, were examined between 2014-2016. Subjects of the urban area of Leipzig were chosen to examine symptoms and signs of TMD. RESULTS: The most prevalent symptom was orofacial pain (13.0%) in the aged participants (n = 192). Temporomandibular joint (TMJ) sounds were the most prevalent sign with values up to 35.5%. Gender comparisons revealed higher prevalence values for the symptom headache/migraine as well as for the signs TMJ sounds (especially clicking sounds) and limited mouth opening in females. Regarding age groups, significant differences were only observed for self-reported headache/migraine. CONCLUSION: Orofacial pain was reported by 13.0% of the subjects and TMJ sounds were observed in every third participant. Similar prevalence values for TMD symptoms and signs in younger and older seniors were found.

Material selection for tooth-supported single crowns-a survey among dentists in Germany.

OBJECTIVES: This study aimed to survey dentists in Germany to identify their favored materials for the fabrication of tooth-supported single crowns (SCs) depending on the location of the abutment teeth and the preparation margin. MATERIALS AND METHODS: The survey included questions regarding demographic characteristics of dentists/their dental practice and preferred restorative materials for the fabrication of SCs for abutment teeth 16, 11, 34, and 36 with either supra- or subgingival preparation margins. RESULTS: Between August 2019 and February 2020, 721 dentists participated in the survey; responses from 33 dentists were excluded from data analysis because the dentists did not work in Germany or provided less than one fixed dental prosthesis/month. Dentists favored ceramic materials independent of the location of the abutment tooth and preparation margin (56.6-92.2%). CAD/CAM resin composites or full metals were preferred by only a few participants. A significantly higher proportion of dentists recommended porcelain fused to metal for subgingival preparation margins than for supragingival margins (p < 0.001). Characteristics of dentists/dental practices influenced a single scenario (11 subgingival) that was dependent on the dentist's time since graduation. When asked to specify the ceramic materials, numerous participants wrote a free response (5.7-7.8%) or did not answer (0.7-4.8%). CONCLUSIONS: Dentists in Germany selected restorative materials for SCs depending on the clinical scenario. Since numerous dentists did not specify the ceramic materials, postgraduate information and education might help to extend expertise. CLINICAL RELEVANCE: The results of this survey provide insight into the favored materials of dentists for the fabrication of tooth-supported SCs.

Patients referred to a German TMD-specialized consultation hour-a retrospective on patients without a diagnosis according to RDC/TMD decision trees.

OBJECTIVES: The objective was to describe the physical and psychosocial features of patients attending a specialized consultation hour for temporomandibular disorders (TMD). This investigation focused on those patients who did not receive a diagnosis according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). MATERIALS AND METHODS: From 2004 to 2017, patients seeking care during a TMD-specialized consultation hour were consecutively recruited. Each patient completed a TMD-related questionnaire, psychosocial questionnaires (Graded Chronic Pain Scale, Hospital Anxiety and Depression Scale, Beschwerden-Liste), and the Oral Health Impact Profile-49. The clinical examination was performed according to the RDC/TMD. RESULTS: The mean age of the 1020 patients was 43.3 years (75.3% female). According to the RDC/TMD decision trees, 351 patients were categorized without a TMD diagnosis (NoTMDdx). The most frequent reasons for seeking care were orofacial pain/TMJ pain or headaches revealing an OR of 1.89 (for TMDdx group). A relevant proportion of patients was categorized as positive for anxiety (NoTMDdx/TMDdx 30.8/41.2%; p = 0.072), depression (20.8/23.9%; p = 0.433), non-specific physical symptoms (31.4/44.1%; p < 0.001), or dysfunctional chronic pain (11.5/18.2%; p < 0.001). In both patient groups, the oral health-related quality of life was impaired (42.9/52.7 points; p < 0.001), and the frequency of therapy measures prior to the consultation hour was high. CONCLUSIONS: Patients seeking care from TMD specialists were usually referred with TMD-associated symptoms. Of those, a relevant proportion did not receive a diagnosis according to RDC/TMD decision trees. CLINICAL RELEVANCE: Psychosocial screening and the avoidance of overtreatment are recommended for patients with TMD-related symptoms.

Interexaminer reliability of the German version of the DC/TMD.

AIM: Verification of the interrater reliability of axis I diagnoses of the German version of the DC/TMD. The hypothesis was that the DC/TMD protocol yields comparable results, if examiner instructions are closely followed. MATERIAL AND METHODS: A culturally equivalent German translation of the DC/TMD was developed. During a 1-day calibration workshop at the University of Heidelberg, three examiners were trained by the DC/TMD Training and Calibration Center. According to the calibration guidelines, 16 models (11 cases, five non-cases) were examined by four experienced TMD specialists. Reliability was calculated with reference to the reference standard examiner as percentage agreement and kappa coefficients for DC/TMD diagnoses and intraclass correlation coefficients (ICCs) for findings. RESULTS: Excellent reliability was achieved for the diagnoses myalgia, myofascial pain with referral, arthralgia, headache attributed to TMD, disc displacement (DD) with reduction, DD without reduction without limited opening (κ = 0.85…1.00). Degenerative joint disease was diagnosed with substantial agreement (κ = 0.64), DD with reduction with intermittent locking and DD without reduction with limited opening were not present in our sample. Overall percentage agreement was 94%-100% for all diagnoses. CONCLUSION: The German version of the DC/TMD shows very good reliability and can be recommended for the use in clinical and research settings.

Rehabilitation of shortened dental arches: A fifteen-year randomised trial.

BACKGROUND: Few long-term studies on treatments in the shortened dental arch (SDA) are available. OBJECTIVE: The objective of this trial was to analyse the long-term success of two different treatment concepts. METHODS: Patients over 35 years of age with missing molars in one jaw and at least the canine and one premolar present on both sides were eligible. In the partial removable dental prosthesis (PRDP) group (N = 81), molars and missing second premolars were replaced by a precision attachment retained prosthesis. In the SDA group (N = 71), the dental arch ended with the second premolar that had to be present or replaced by a cantilever fixed dental prosthesis. Follow-up examinations were carried out over 15 years. RESULTS: A comprehensive outcome variable comprised four failure categories for which Kaplan-Meier survival (success) analyses were conducted. Half of the patients exhibited a continuous preservation of the per protocol prosthetic status that remained totally unaffected by complications for more than 10 years. The event-free success rates for moderate or worse failure implied a loss of the per protocol prosthetic status. The respective survival rates fell below 50% at 14.2 years in the PRDP group and 14.3 years in the SDA group. In none of the analyses, a significant group difference was found. CONCLUSIONS: In patients with an SDA condition, changes in the prosthetic status have to be expected. The affected proportion increases almost linearly from shortly after treatment and comprises the majority after 15 years. The influence of the examined treatments on success appears to be low.

Material preferences for tooth-supported 3-unit fixed dental prostheses: A survey of German dentists.

STATEMENT OF PROBLEM: Different material options are available for fixed dental prostheses (FDPs), but valid data on the favored materials of German dentists for 3-unit FDPs are lacking. It is unclear whether preferences depend on the individual characteristics of the dentists or their dental practices. PURPOSE: The purpose of this survey was to identify the preferred material selection of German dentists for the fabrication of tooth-supported 3-unit FDPs depending on the location of the abutment teeth and the individual characteristics of the dentist or the dental practice. MATERIAL AND METHODS: A survey was developed that included questions on the demographic characteristics (sex, area of expertise, age group, time since graduation, number of inhabitants, and the postal code of the dental practice or dental school) of the participating dentist and their preferred materials for the fabrication of tooth-supported 3-unit FDPs. Three clinical scenarios (anterior maxillary FDP, posterior maxillary FDP, posterior mandibular FDP) were presented. The dentists were allowed to select from predefined options or to give a free answer. For comparisons of characteristic associations, the number of inhabitants was chosen to represent the characteristics of the dental practice, and sex and time since graduation were selected to represent the characteristics of the dentist. Group comparisons were conducted with Chi-square tests (α=.05). RESULTS: A response of 721 dentists from all parts of Germany was received, and data from 688 dentists were included in the analyses. Ceramic was the most preferred material for the fabrication of 3-unit FDPs independent of the location of the abutment teeth with veneered zirconia as the favored option. Metal-ceramic was ranked second. The time since graduation ≤15 years was associated with a preference of ceramic over metal-ceramic for the anterior restoration (P<.001). CONCLUSIONS: Most participating dentists selected appropriate restorative materials depending on the individual clinical setting presented in the survey. For the anterior 3-unit FDP, time since graduation was associated with the preference for a restorative material. Some dentists selected lithium-X-silicate ceramics for situations beyond their recommended indication range.

Impact of cement type and abutment height on pull-off force of zirconia reinforced lithium silicate crowns on titanium implant stock abutments: an in vitro study.

BACKGROUND: Pull-off forces of cement-retained zirconia reinforced lithium silicate (ZLS) in implant-supported single crowns on stock titanium abutments with respect to abutment height and implant cement were evaluated and compared. METHODS: Pull-off force of ZLS crowns on stock titanium abutments was evaluated concerning dental cement and abutment height. A total sample size of 64 stock abutments with heights of 3 mm (n = 32) and 5 mm (n = 32) was used. The ZLS crowns were cemented with four different types of cement (one temporary, two semi-permanent, and one permanent). After cementation, water storage, and thermocycling each sample was subjected to a pull-off test using a universal testing machine. RESULTS: The temporary cement showed the least pull-off force regardless of abutment height (3/5 mm: means 6 N/23 N), followed by the semi-permanent methacrylate-infiltrated zinc oxide cement (28 N/55 N), the semi-permanent methacrylate-based cement (103 N/163 N), and the permanent resin composite cement (238 N/820 N). Results of all types of cement differed statistically significantly from each other (p ≤ .012). The type of implant cement has an impact on the pull-off force of ZLS crowns and titanium abutments. CONCLUSIONS: Permanent cements present higher retention than semi-permanent ones, and temporary cements present the lowest values. The abutment height had a subordinate impact.

Impact of the DC/TMD instructional video on the practical skills of undergraduate students-A single-blinded, randomized controlled trial.

INTRODUCTION: Competencies in the clinical examination of patients with temporomandibular disorders (TMD) can be achieved by self-instruction. This study aimed to identify the impact of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) instructional video on the practical examination skills of undergraduate students. MATERIALS AND METHODS: One week prior to completing an objective structured clinical examination (OSCE) addressing the examination of patients with TMD, undergraduate students in their third year received either the DC/TMD manual (control group) or additionally watched the instructional video once (intervention group). After passing the OSCE, a feedback questionnaire was completed by the students. RESULT: Fifty undergraduates were recruited to take part in the OSCE prior to their first clinical course. The sum scores achieved in the stations were higher in the intervention group, but missed significance. Participants of the intervention group more often agreed that completing the OSCE stations was easy, which was significant for one station (P = .023). 95.8% of the participating students supported the implementation of the video in dental education. DISCUSSION: Due to the conception of the study, the video was only presented once to ensure that the control group had no access to the medium at all. However, it might be interesting to investigate whether repeated watching of the video enhances its effect. CONCLUSIONS: Clinical competencies in the examination of TMD patients can be achieved by self-instruction with the DC/TMD manual and instructional video. Watching the video for educational purposes was highly recommended by undergraduate students.

CLEANING OF REMOVABLE DENTAL PROSTHESES - A SYSTEMATIC REVIEW.

Objectives The aim of this systematic review was to provide an overview of the scientific evidence available from prospective clinical studies regarding denture hygiene interventions. Therefore, investigations addressing the efficacy of removing microorganisms and biofilms formed on the surface of removable dental prostheses (RDPs) and denture base materials in situ and their impact on the properties of denture base materials, such as color stability, surface roughness, and dimensional stability, were included. Methods A systematic literature search was conducted from June 1975-May 2020 and included articles published in English that have been indexed in the digital archives of PubMed and Cochrane (including PubMed, Embase, ICTRP, CT.gov). A complementary manual search of the initially retrieved studies was conducted. Inclusion criteria comprised prospective clinical trials with a minimum of ten participants investigating (1) approaches and methods to remove biofilms formed on the surface of RDPs and denture base materials in situ and/or (2) the influence of these biofilms on denture base materials. A total of forty-four studies were included in this systematic review, which was registered in the PROSPERO database (CRD42020189649). Results and Conclusions Data gathered from the systematic review indicate that the combined use of chemical and mechanical denture hygiene interventions is significantly more effective than single cleaning approaches. Only limited evidence is available from clinical studies regarding the effect of denture hygiene interventions on the properties of denture base materials.

IMPACT OF SHORTENED DENTAL ARCH ON ORAL HEALTH-RELATED QUALITY OF LIFE.

BACKGROUND: A shortened dental arch (SDA) is an established treatment concept for patients with missing molars. However, little is known regarding long-term course of oral health-related quality of life (OHRQoL) in patients with SDA and the benefits from replacement of missing molars. OBJECTIVE: Purpose of this multi-center randomized clinical trial was to assess OHRQoL over a period of 15 years in patients with molar replacement by a removable partial denture (RPD) compared to patients with a restored SDA without molar replacement. METHODS: Patients at least 35 years of age with all molars missing in 1 jaw and at least the canine and one premolar present on each side were included. Patients received either a precision attachment-retained, RPD for replacement of missing molars (n = 79), or the dental arch ended with the second premolar (SDA) that had to be present or replaced by a cantilever fixed dental prosthesis (n = 71). Follow-up examinations continued for 15 years. OHRQoL was assessed with the 49-item Oral Health Impact Profile (OHIP). OHIP summary and dimension scores were longitudinally modeled in the statistical analyses to assess course of OHRQoL over time applying an intention-to-treat approach. In addition, scores for the OHRQoL dimensions Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact were analyzed. RESULTS: After an initial improvement in OHRQoL indicated by a mean decrease of 20.0 OHIP points with an effect size of 0.61 in the entire study population, OHRQoL stayed relatively constant over the entire follow-up period. Assuming a constant time and treatment effects over the study period, OHRQoL did not differ statistically significant between the 2 treatments (0.4 OHIP points; 95%-CI: 7.1 - 6.2). OHRQoL after treatment did not change notably over 15 years and was statistically nonsignificant as well (P = .872). Similar findings were observed in all 4 OHRQoL dimensions. CONCLUSIONS: In patients, missing all molars in one jaw OHRQoL improved providing RPD or restoring SDA to a clinically relevant degree. Treatment-related improvement remained mostly stable over a period of at least 15 years. Therefore, patients can be informed that both treatment concepts are equivalent concerning long-term OHRQoL. Accordingly, patients' preferences regarding treatment options should be granted priority in treatment decision making with the SDA treatment option being the default.

Adhesive luting of orthodontic devices to silica-based ceramic crowns-comparison of shear bond strength and surface properties.

OBJECTIVES: The aim of this study was to analyse the impact of different clinical conditioning approaches and an ammonium polyfluoride- and trimethoxysilylpropyl methacrylate-based experimental primer for intraoral luting of buccal tubes on silica-based ceramic surfaces. MATERIALS AND METHODS: A total of 60 leucite-reinforced glass ceramic molar crowns were conditioned using different methods (n = 10): I-roughening, hydrofluoric acid, silane; II-roughening, silane; III-roughening, experimental coupling agent; IV-experimental coupling agent; V-roughening; VI-no treatment. A buccal tube was adhesively luted to the ceramic surface. Subsequently, water storage, thermocycling and chewing simulation were carried out. The shear bond strength (SBS) was determined, and changes in the surface were assessed. RESULTS: All tubes of the control group (group VI) debonded after incubation. The conditioning methods using coupling agents revealed mean values for SBS of 61.56 MPa (group I), 45.53 MPa (group III), 41.65 MPa (group II), and 23.14 MPa (group IV). In groups I-III, both composite residues and cracks/tear-outs were detected. CONCLUSIONS: The conditioning of silicate ceramic surfaces with a suitable coupling agent system appears to allow sufficient adhesive luting of buccal tubes. The intraoral luting of fixed appliance elements on silicate ceramic surfaces using an ammonium polyfluoride- and trimethoxysilylpropyl methacrylate-based ceramic primer can withstand orthodontic forces. CLINICAL RELEVANCE: Ammonium polyfluoride- and trimethoxysilylpropyl methacrylate-based ceramic primers revealed promising results for the intraoral adhesive luting of orthodontic devices to silica-based ceramic crowns.

Prevalence of anamnestic symptoms and clinical signs of temporomandibular disorders in adolescents-Results of the epidemiologic LIFE Child Study.

BACKGROUND: Prevalence values for symptoms and signs of temporomandibular disorders (TMD) in adolescents vary within the literature due to differences in set-ups of examination protocols. OBJECTIVES: The objective was to present prevalence values for symptoms and signs of TMD in German adolescents that were observed within a standardised examination. Prevalence values comparing gender or pubertal status should be investigated. METHODS: A cross-sectional sample of the LIFE Child Study aged 10 to 18 was examined. A questionnaire gathering anamnestic symptoms of TMD was completed, and an examination according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) was performed by trained dentists. Pubertal status according to Tanner stages was documented. Descriptive statistics, Mann-Whitney U and Wilcoxon signed-rank tests were performed. RESULTS: A total of 1.116 participants (mean age 12.9 years, 51.4% female) were consecutively recruited. Most prevalent anamnestic symptoms were headaches (55.7%) and temporomandibular joint (TMJ) sounds (17.6%). The major clinical sign was TMJ sounds (31.9%). Both the examination of muscles or TMJs showed that pain to palpation was statistically significantly higher than familiar pain (P < .001). Gender comparisons revealed higher prevalence values and an increase in TMD symptoms and signs during pubertal development in females. CONCLUSION: The prevalence of self-reported headaches, as well as anamnestic and clinical TMJ sounds, was high in German adolescents. Prevalence values for pain to palpation and familiar pain obtained relevant differences. Considering the DC/TMD, females are more affected by TMD signs and symptoms that increase during pubertal development, than male adolescents.