Proposing a communication module to enhance dental students' attitudes towards people with dementia: Phase 1 of a curriculum revision study.

INTRODUCTION: The number of mentally altered patients a dentist meets in practice is increasing and interaction with them can be very challenging. As a baseline for an interventional study, we want to assess the attitude of dental students and identify areas of improvement in patient communication. This work compares the attitude of dental students towards people suffering from dementia to the attitudes of trained medical caregivers and the general population. Our aim is to use the results to assess the need for training in communicating with mentally altered patients. MATERIALS AND METHODS: Fourth-year dental students attended two lectures on dementia given by a psychiatrist as part of the geriatric dentistry lecture and were questioned afterwards using the Dementia Attitude Scale. In 2016 and 2017, 73 students at the University of Greifswald were interviewed. The response rate was 84%. Using a factor analysis, the Dementia Attitude Scale's validated questions were interpreted and compared with data from nursing staff from Switzerland and the USA. RESULTS: The factor analysis of the data showed the same two-factor loadings as the comparative groups, and that dental students' attitude is more comparable to the general population than to medically trained nursing staff. CONCLUSION: Given the results, we conclude that the implementation of a communication module can serve in improving the attitude of dental students towards patients with dementia.

Fused filament fabrication (FFF): influence of layer height on forces and moments delivered by aligners-an in vitro study.

OBJECTIVES: To investigate the effect of layer height of FFF-printed models on aligner force transmission to a second maxillary premolar during buccal torquing, distalization, extrusion, and rotation using differing foil thicknesses. MATERIALS AND METHODS: Utilizing OnyxCeph3™ Lab (Image Instruments GmbH, Chemnitz, Germany, Release Version 3.2.185), the following movements were programmed for the second premolar: buccal torque (0.1-0.5 mm), distalization (0.1-0.4 mm), extrusion (0.1-0.4 mm), rotation (0.1-0.5 mm), and staging 0.1 mm. Via FFF, 91 maxillary models were printed for each staging at different layer heights (100 µm, 150 µm, 200 µm, 250 µm, 300 µm). Hence, 182 aligners, made of polyethylene terephthalate glycol (PET-G) with two thicknesses (0.5 mm and 0.75 mm), were prepared. The test setup comprised an acrylic maxillary model with the second premolar separated and mounted on a sensor, measuring initial forces and moments exerted by the aligners. A generalized linear model for the gamma distribution was applied, evaluating the significance of the factors layer height, type of movement, aligner thickness, and staging on aligner force transmission. RESULTS: Foil thickness and staging were found to have a significant influence on forces delivered by aligners, whereas no significance was determined for layer height and type of movement. Nevertheless, at a layer height of 150 µm, the most appropriate force transmission was observed. CONCLUSIONS: Printing aligner models at particularly low layer heights leads to uneconomically high print time without perceptible better force delivery properties, whereas higher layer heights provoke higher unpredictability of forces due to scattering. A z-resolution of 150 µm appears ideal for in-office aligner production combining advantages of economic print time and optimal force transmission.

Survival and stability of strategic mini-implants with immediate or delayed loading under removable partial dentures: a 3-year randomized controlled clinical trial.

OBJECTIVES: Stability values of mini-implants (MIs) are ambiguous. Survival data for MIs as supplementary abutments in reduced dentitions are not available. The aim of this explorative research was to estimate the 3-year stability and survival of strategic MIs after immediate and delayed loading by existing removable partial dentures (RPDs). MATERIAL AND METHODS: In a university and three dental practices, patients with unfavorable tooth distributions received supplementary MIs with diameters of 1.8, 2.1, and 2.4 mm. The participants were randomly allocated to group A (if the insertion torque ≥ 35 Ncm: immediate loading by housings; otherwise, immediate loading by RPD soft relining was performed) or delayed loading group B. Periotest values (PTVs) and resonance frequency analysis (RFA) values were longitudinally compared using mixed models. RESULTS: A total of 112 maxillary and 120 mandibular MIs were placed under 79 RPDs (31 maxillae). The 1st and 3rd quartile of the PTVs ranged between 1.7 and 7.8, and the RFA values ranged between 30 and 46 with nonrelevant group differences. The 3-year survival rates were 92% in group A versus 95% in group B and 99% in the mandible (one failure) versus 87% in the maxilla (eleven failures among four participants). CONCLUSIONS: Within the limitations of explorative analyses, there were no relevant differences between immediate and delayed loading regarding survival or stability of strategic MIs. CLINICAL RELEVANCE: The stability values for MIs are lower than for conventional implants. The MI failure rate in the maxilla is higher than in the mandible with cluster failure participants. CLINICAL TRIAL REGISTRATION: German Clinical Trials Register (Deutsches Register Klinischer Studien, DRKS-ID: DRKS00007589, www.germanctr.de ), January 15, 2015.

Training of the lateral pterygoid muscle in the treatment of temporomandibular joint disc displacement with reduction: A randomised clinical trial.

BACKGROUND: Disc displacement with reduction (DDwR) therapy should be performed only when pain or discomfort is presented. Data on treatment options for painful DDwR are very limited. OBJECTIVE: The aim was to investigate whether isometric training of the lateral pterygoid muscle (LPM) is equivalent to stabilisation appliance therapy with regard to the treatment of painful DDwR. The training program is based on the science of Janda. METHODS: This was a prospective, randomised study with a comparative treatment group. Sixty patients (≥18 years) with DDwR and pain were randomly assigned to two groups: (1) muscle training and (2) stabilisation appliance. The following variables were recorded at baseline examination and after 2, 4 and 6 months: changes in orofacial pain, clicking sounds of the temporomandibular joint (TMJ), force degrees for the lateral movement of the mandible and interincisal opening distance. p values of <.05 were considered statistically significant but 95% confidence intervals were also presented. RESULTS: A decrease in orofacial pain intensity was seen in both groups (p < .0001). Registered TMJ clicking disappeared after 6 months of treatment in 37% (n = 11) of the patients in the training group and in 27% (n = 8) of the appliance group (p = .0009 and p = .0047). Muscle training showed 27 improvements in Janda force degrees at the end of the study (p < .0001). CONCLUSION: Muscle training and appliance therapy improved mouth opening and reduced pain intensity in both patient groups. Muscle training might be a promising option in the treatment of patients suffering from painful DDwR.

Cephalometric analyses for cleft patients: a statistical approach to compare the variables of Delaire's craniofacial analysis to Bergen analysis.

OBJECTIVES: Cephalometric analyses using lateral craniofacial radiographs are common diagnostic procedures for evaluating skeletal patterns. However, in patients with pronounced abnormalities like cleft lip and palate, standard cephalometric analyses and landmarks may not be suitable. This study aims to clarify whether the inclusion of landmarks less compromised by the cleft defect or located outside the cleft area results in a different cephalometric assessment of the viscerocranium. Delaire's whole-skull analysis and Bergen analysis were examined for similarities and underlying common observations. MATERIALS/METHODS: Based on the cephalometric evaluation of 217 patients with different types of non-syndromal cleft formation, Delaire and Bergen analysis were compared using three statistical methods: correlation analysis, factor analysis, and cluster analysis. Reproducibility was assessed by Bland-Altman plots, intraclass correlation coefficients, mean absolute differences, and coefficients of variability. RESULTS: Although Delaire analysis and Bergen analysis are based on different concepts and landmarks, a majority of corresponding variables was found. Certain aspects of craniofacial base relation and craniospinal articulation are only assessed by Delaire analysis. All but one variable showed very good reproducibility. CONCLUSIONS: The inclusion of landmarks less compromised by or located outside the cleft area does not result in variables that provide a different assessment of the viscerocranial area. CLINICAL RELEVANCE: The findings contradict the concept of invalidity of landmarks compromised by the cleft defect or located within the affected cleft area. Within the scope of its viscerocranial field of view, Bergen analysis appears to be on a par with Delaire analysis in the diagnosis of cleft patients.

Effect of periodontal treatment on preclinical Alzheimer's disease-Results of a trial emulation approach.

INTRODUCTION: We investigated the relationship between periodontal treatment and pre-clinical Alzheimer's disease (AD). METHODS: In this quasi-experimental design, 177 periodontally treated patients from the "Greifswald Approach to Individualized Medicine" cohort, which used the same protocols as the population-based Study of Health in Pomerania TREND (SHIP-TREND), and 409 untreated subjects from SHIP-TREND were analyzed. Subjects were younger than 60 years at the magnetic resonance imaging examination, with a median observation period of 7.3 years. Imaging markers for brain atrophy in late-onset AD and brain aging were used as the outcomes. RESULTS: Robust to sensitivity analyses, periodontal treatment had a favorable effect on AD-related brain atrophy (-0.41; 95% confidence interval: -0.70 to -0.12; P = .0051), which corresponds to a shift from the 50th to the 37th percentile of the outcome distribution. For brain aging, the treatment effect was uncertain. CONCLUSION: Periodontitis is related to pre-clinical AD in our population.

What German dentists choose for their teeth: A Web-based survey of molar restorations and their longevity.

STATEMENT OF PROBLEM: Which restorative material is best suited for treating the posterior molar region is unclear. As dentists presumably choose the most appropriate restoration, German dentists were asked how their own molars were treated. PURPOSE: The purpose of this survey study was to examine molar restorations and their durability in German dentists. MATERIAL AND METHODS: In the official journal of the Federal Dental Association, German dentists were asked to participate in an online survey that gathered demographic data and information on the type and durability of their molar restorations. To reduce selection bias, the data were weighted for region, sex, and age of the dentist. RESULTS: The data set consisted of 1719 molars from 288 dentists. Restorations included gold inlays (25%), composite resin (24.3%), amalgam (11.8%), ceramic inlays (5.4%), glass ionomer cement or compomer (0.8%), gold crowns (21.8%), ceramic crowns (6.6%), and metal-ceramic crowns (4.3%). Notable differences were identified based on the sex, age, and region of the dentist. Women selected increased esthetic options, as did young dentists. Restorations made of gold, amalgam, and base metal had the highest longevity, at more than 20 years CONCLUSIONS: Among German dentists, restorations with metallic materials dominated in molars, with gold accounting for the largest share. In recent years, the proportion of tooth-colored restorations has increased, and in particular, young dentists use composite resin and ceramics.

New insights in the link between malocclusion and periodontal disease.

AIM: We aimed to investigate associations between malocclusions and periodontal disease by comparing it to that of smoking in subjects recruited from the population-based cross-sectional study "Study of Health in Pomerania." MATERIALS AND METHODS: Sagittal intermaxillary relationship, variables of malocclusion and socio-demographic parameters of 1,202 dentate subjects, 20-39 years of age, were selected. Probing depth (PD) and attachment loss (AL) were assessed at four sites by tooth in a half-mouth design. Analyses were performed with multilevel models on subject, jaw and tooth level. RESULTS: Distal occlusion determined in the canine region, ectopic position of canines, anterior spacing, deep anterior overbite and increased sagittal overjet were associated with AL (p-value <0.05). Associations between malocclusions and PD: deep anterior overbite with gingival contact (odds ratio [OR] = 1.40, 95% CI: 1.08-1.82; p-value = 0.0101) and anterior crossbite (OR = 1.75, 95% CI: 1.29-2.38; p-value = 0.0003). Regarding crowding, only severe anterior crowding was compatible with a moderate to large association with PD (OR = 1.93, 95% CI: 0.89-4.20). Compared to smoking, the overall effect of malocclusions was about one half for AL and one-third for PD. CONCLUSION: Malocclusions or morphologic parameters were associated with periodontal disease.

Alexithymia and temporomandibular joint and facial pain in the general population.

BACKGROUND: Associations of alexithymia with temporomandibular pain disorders (TMD), facial pain, head pain and migraine have been described, but the role of the different dimensions of alexithymia in pain development remained incompletely understood. OBJECTIVES: We sought to investigate the associations of alexithymia and its subfactors with signs of TMD and with facial pain, head pain and migraine in the general population. METHODS: A total of 1494 subjects from the general population completed the Toronto Alexithymia Scale-20 (TAS-20) and underwent a clinical functional examination with palpation of the temporomandibular joint and masticatory muscles. Facial pain, migraine and head pain were defined by questionnaire. A set of logistic regression analyses was applied with adjustment for age, sex, education, number of traumatic events, depressive symptoms and anxiety. RESULTS: Alexithymia was associated with TMD joint pain (Odds Ratio 2.63; 95% confidence interval 1.60-4.32 for 61 TAS-20 points vs the median of the TAS-20 score) and with facial pain severity (Odds Ratio 3.22; 95% confidence interval 1.79-5.79). Differential effects of the subfactors were discovered with difficulties in identifying feelings as main predictor for joint, facial, and head pain, and externally oriented thinking (EOT) as U-shaped and strongest predictor for migraine. CONCLUSION: Alexithymia was moderately to strongly associated with signs and symptoms of TMD. These results should encourage dental practioners using the TAS-20 in clinical practice, to screen TMD, facial or head pain patients for alexithymia and could also help treating alexithymic TMD, facial or head pain patients.

Reducing uncertainty in estimating associations of oral exposures with Helicobacter pylori serology in the general population.

AIM: Evidence for reducing Helicobacter (H.) pylori by periodontal therapy comes from small studies in China, limiting generalizability. To estimate the association between periodontal disease and anti-H. pylori IgG titer levels in a European country, we used population-based data from the Study of Health in Pomerania. MATERIALS AND METHODS: For pocket depth as the primary exposure, we restricted the age range to participants younger than 60 years (n = 2,481) to avoid selection bias due to edentulism in this cross-sectional study. For the full age range up to 81 years, we chose the number of missing teeth (n = 3,705). RESULTS: The association between pocket depth and the outcome was weak. Given the ceiling effect for the number of missing teeth (ordinal logistic regression; odds ratio of the interquartile range effect = 1.6; 95% CI: 1.3-1.9; p-value for linearity = 0.005), we checked whether wearing removable dental prosthesis was associated with higher anti-H. pylori IgG titer levels (odds ratio = 1.3; 95% CI: 1.1-1.5). CONCLUSIONS: Tooth loss and wearing removable dental prosthesis were weakly to moderately associated with higher anti-H. pylori IgG titer levels in the general population of a European country.

Association of salivary peroxidase activity and concentration with periodontal health: A validity study.

AIM: Whereas the relationship between myeloperoxidase and periodontitis has been widely examined that between salivary peroxidase and periodontitis has received little attention. We examined how periodontitis depends on both salivary peroxidase activity and concentration. MATERIALS AND METHODS: A full mouth, clinical assessment of probing depth was performed in a sample of 46 participants aged 25-54 years. To minimise bias, these data were corrected by data from the general population (Study of Health in Pomerania). Using five repeated measurements of activity and concentration over 1 day, we assessed daily biological variability and increased the reliability of salivary peroxidase measurements. RESULTS: Salivary peroxidase activity was associated with probing depth (interquartile range effect = -0.48; robust estimates of 95% confidence interval: -0.90 to -0.31; p = .0052), and its effect was not confounded by salivary peroxidase concentration. In turn, the effect of salivary peroxidase concentration was confounded by salivary peroxidase activity, and it was smaller than that of activity. CONCLUSIONS: We found an inverse association between salivary peroxidase activity and probing depth. Thus, our results imply that salivary peroxidase activity could be a protective factor against periodontitis. However, large, well-designed studies are needed to explore the causal mechanisms of this association.

Immediate versus delayed loading of strategic mini dental implants for the stabilization of partial removable dental prostheses: a patient cluster randomized, parallel-group 3-year trial.

BACKGROUND: Acceptable short-term survival rates (>90 %) of mini-implants (diameter < 3.0 mm) are only documented for mandibular overdentures. Sound data for mini-implants as strategic abutments for a better retention of partial removable dental prosthesis (PRDP) are not available. METHODS/DESIGN: The purpose of this study is to test the hypothesis that immediately loaded mini-implants show more bone loss and less success than strategic mini-implants with delayed loading. In this four-center (one university hospital, three dental practices in Germany), parallel-group, controlled clinical trial, which is cluster randomized on patient level, a total of 80 partially edentulous patients with unfavourable number and distribution of remaining abutment teeth in at least one jaw will receive supplementary min-implants to stabilize their PRDP. The mini-implant are either immediately loaded after implant placement (test group) or delayed after four months (control group). Follow-up of the patients will be performed for 36 months. The primary outcome is the radiographic bone level changes at implants. The secondary outcome is the implant success as a composite variable. Tertiary outcomes include clinical, subjective (quality of life, satisfaction, chewing ability) and dental or technical complications. DISCUSSION: Strategic implants under an existing PRDP are only documented for standard-diameter implants. Mini-implants could be a minimal invasive and low cost solution for this treatment modality. TRIAL REGISTRATION: The trial is registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00007589 ( www.germanctr.de ) on January 13(th), 2015.

Resin-based pit-and-fissure sealants: microleakage reduction and infiltration enhancement using a bonding agent.

PURPOSE: To evaluate the marginal microleakage and the infiltration ability of pit-and-fissure sealants by applying the conventional sealing technique in comparison to using an additional bonding agent. MATERIALS AND METHODS: Extracted non-carious permanent molars (n = 60) were first stored in sterile saline solution and then assigned to one of two groups: group C (control) was sealed (Helioseal F) by using the conventional technique, while in group BA (bonding agent), a bonding agent (OptiBond FL) was additionally applied prior to sealing. The teeth were thermocycled (1000 cycles, 5°C to 55°C, dwell time 30 s), then varnished and immersed in 5% methylene blue solution for 24 h. After embedding and sectioning each tooth into 6-12 slices, the presence of microleakage, unfilled areas, and air bubbles trapped in the sealant were assessed with a stereomicroscope. RESULTS: A higher proportion of microleakage was found under sealants applied without the additional use of the bonding agent. A statistically significant difference in microleakage was noted between the groups (p = 0.045). Regarding the presence of unfilled areas, a statistically significant difference between the groups was observed (p < 0.001), especially since no unfilled areas were found at all in the samples of the group using the bonding agent. Regarding the amount of air bubbles trapped in the sealant, no statistically significant difference was observed between the two groups (p = 0.829). CONCLUSION: Under these in vitro conditions, sealant procedures using an additional bonding agent applied beforehand significantly improved fissure infiltration and microleakage prevention significantly.

Clinical response of edentulous people treated with mini dental implants in nine dental practices.

OBJECTIVES: To analyse implant survival, prosthetic aftercare and quality of life (QoL) after stabilisation of complete dentures with mini-implants. BACKGROUND: Many edentulous patients refuse implant therapy due to the expenses and fear of surgery. Studies on minimally invasive and low-cost mini-implants remain rare. MATERIALS AND METHODS: A total of 133 participating patients from nine private practices were evaluated via patient records, questionnaires and clinical examinations. Complications, maintenance, QoL questions and the German short version of the oral health impact profile (OHIP-G14) were analysed. RESULTS: After 7 to 61 months, 15 of 336 maxillary implants and 11 of 402 mandibular implants had to be removed. In addition, four mandibular implants experienced fracture. The difference between the 4-year survival rates of 94.3% for the maxilla and 95.7% for the mandible was not statistically significant (p = 0.581). All original 144 overdentures remained functional. The prosthetic interventions were typically limited to repairs of acrylic base fractures (about one in five patients), changes of plastic O-rings and relining procedures. The participants showed OHIP-G14 scores (median = 2) that were comparable with those of patients with overdentures retained by conventional implants. CONCLUSIONS: Mini-implant survival was similar to that of regular-diameter implants. Although some prosthetic aftercare was necessary, none of the overdentures had to be replaced. Prospective studies comparing conventional and mini-implants are warranted.

High social support buffers the effects of 5-HTTLPR genotypes within social anxiety disorder.

An interaction between genetic aspects and environmental stressors has been suggested with regard to the etiology of social anxiety disorder (SAD). However, potential protective interplays which might decrease the risk of SAD have not been considered so far. Thus, we analyzed the interaction between 5-HTTLPR and differing levels of social support regarding SAD. The sample was based on participants of the Study of Health in Pomerania, Germany. We used the triallelic genotype of 5-HTTLPR and longitudinal data of social support. Final analyses were conducted in 79 individuals with SAD and 1,708 without. The diagnosis of SAD was derived from diagnostic interviews in accordance with DSM-IV. Considering the risk of SAD, a general protective effect of high social support was shown independent of variation in 5-HTTLPR genotype. In contrast, the risk of SAD was increased for both genotypes within those individuals with low social support. Additionally, the odds ratio for suffering from SAD was about two times higher for carriers of the l/l genotype compared to those with at least one short allele in those perceiving less-supportive social environments. The findings suggest that SAD is influenced by a protective and a contributing gene × environment interaction. High social support might act in a protective and low social support in an increasing manner on the risk of SAD especially within carriers of the l/l genotype. Therefore, effects of 5-HTTLPR might be buffered by high social support with respect to the risk of SAD.

The intra- and inter-rater reproducibility of bone level measurements at strategic mini-implants using dental panoramic radiography.

OBJECTIVES: This experimental study focused on the intra- and inter-rater reproducibility of vertical bone level (VBL) measurements at strategic mini-implants (MI) using digital panoramic radiographs (PR). STUDY DESIGN: VBLs of 152 MIs for removable partial denture stabilization at 50 randomly chosen PRs from a clinical trial were digitally evaluated by three ratters. Rater deviations exceeding 0.5 mm were re-examined. The intra-class correlation coefficient (ICC) was applied to estimate reliability. The smallest detectable change (SDC) was interrelated to the minimal clinically important change of 0.2 mm. RESULTS: The first measurement round revealed intra- and inter-rater ICCs of > 0.8. However, 28 sites (9 %) were unreadable, and 97 sites (32 %) revealed differences between observers of ≥ 0.5 mm. Following a consensus session and re-training, an additional 8 sites were excluded and all remaining VBL differences were ≤ 0.5 mm. Thus, the SDCs with 95 % credibility were improved from 0.73 to 0.31 mm in the intra-rater and from 1.52 to 0.34 mm in the inter-rater statistics. Given a 50 % credibility for this special setting, both the intra- and inter-rater SDCs were 0.11 mm. CONCLUSIONS: Digital PR can be reliably utilized to determine VBLs around MIs under conditions of at least two trained observers, mutual calibration sessions, and exclusion of unquantifiable radiographs. GERMAN CLINICAL TRIALS REGISTER ID: DRKS00007589, www.germanctr.de.

Impact of depressive symptoms on prosthetic status--results of the study of health in Pomerania (SHIP).

OBJECTIVES: Previous investigations have confirmed that every fifth dental patient suffers from clinically significant depressive symptoms. However, the putative impact of depressive symptoms on the prosthetic status has not been addressed in these studies. The objective of this study was to investigate the association between depressive symptoms and prosthetic status based on data from the Study of Health in Pomerania (SHIP-0). METHODS: Data from 2,135 participants aged 30 to 59 years were analyzed. A classification (six classes regarding the number and position of missing teeth per jaw) was used to identify the degree of prosthetic status (no/suboptimal/optimal tooth replacement). The presence of depressive symptoms was assessed with a modified version of von Zerssen's complaints scale. Screening for lifetime diagnoses of mental disorders was performed with the Composite International Diagnostic-Screener (CID-S). Multivariable logistic regressions including several confounders were calculated. RESULTS: A significant protective dose-response effect of depressive symptoms on prosthetic status was found only in men for the lower jaw [0-1 depressive symptoms: odds ratio (OR) = 3.84, 95 % confidence interval (CI, 1.65-8.92), p < 0.01; 2-3: OR = 2.87 (CI, 1.22-6.74), p < 0.05; reference, ≥8; adjusted for age, school education, smoking status, household income, marital status, living without a partner, risky alcohol consumption, obesity, diabetes, and physical activity]. There was no such association in women or for the upper jaw. The analyses using the CID-S confirmed these results. CONCLUSIONS: In the lower jaw, men with depressive symptoms had a better prosthetic status than men without depressive symptoms suggesting a higher level of concern regarding their personal health. CLINICAL RELEVANCE: If dentists might have an opportunity to identify men with depressive symptoms they can provide a wide range of treatment options that may enhance patients' self-esteem and contribute to the patient' well-being. Furthermore, depressive symptoms could indicate a discrepancy between self-perception of the dental health and the actual status which influence the dentists' treatment decision making.

Retrospective and clinical evaluation of retrievable, tooth-implant supported zirconia-ceramic restorations.

OBJECTIVE: Permanent cementations of zirconia-ceramic restorations may conflict with the rationale for retrievability of implant-supported restorations. The aim of this study was to test the hypothesis that retrievable, tooth-implant supported FDPs made of veneered zirconia ceramic cores are a viable treatment alternative. MATERIAL AND METHODS: Restorations of patients in private practice and dental clinic were evaluated by reviewing patient records retrospectively and performing a final clinical examination. Permanently cemented copings protected the tooth abutments. The zirconia-ceramic restorations were semi-permanently cemented to the copings and the implant abutments using acrylic-urethane cement. In addition to Kaplan-Meier analyses for complications, the effect of age, gender, signs of bruxism, jaw and number of units on complications was estimated using Cox regression analyses (significance p < 0.05). RESULTS: The follow-up period for 23 patients (nine with signs of bruxism) with four anterior and 27 posterior zirconia-ceramic restorations (3-12 units) ranged from 12.7-47.9 months. Core fractures of two posterior prostheses in patients with signs of bruxism yielded a 40-month survival rate of 93.5%. There were 10 cohesive chippings within the veneering porcelain for seven patients (six patients with signs of bruxism), which resulted in 40-month chipping rates of 5.6% among non-bruxers and 100% among patients with signs of bruxism. The hazard ratio for signs of bruxism was 20 (95% confidence interval: 2.1-188.3, p = 0.009). CONCLUSIONS: Retrievable, tooth-implant supported restorations made of zirconia-ceramics should be used with caution because of some core fractures and a considerable number of minor veneer fractures. The fracture risk was very high among patients with signs of bruxism. Due to the low number of occasions for intentional retrievals, a recommendation to use semi-permanently cemented, all-ceramic FDPs would still be premature.

Effects of different manual periodontal probes on periodontal measurements.

AIM: To quantify the digit preference effect for three manual periodontal probes and to calculate correction values to enable comparison of studies with equal recording protocols, but different periodontal probes. MATERIAL AND METHODS: A prospective in vivo crossover study was conducted with a six-sequence three-period design. Six examiners assessed attachment loss (AL), probing pocket depth (PD) and gingiva height (GH) at four surfaces, full-mouth, in six generally healthy subjects using three manual probes: PCP11 (3-3-3-2 mm increments), PCP2 (2 mm increments), and PCPUNC15 (1 mm increments). RESULTS: Distributions of AL, PD and GH differed between probes (p < 0.001). Compared with PCPUNC15, periodontal measurements coinciding with probe markings of PCP11 and PCP2, respectively, were preferentially named by examiners. Digit preference was most pronounced for PD, but less for AL and GH. In multilevel models, PD differed significantly between all three probes (p < 0.05); probe- and examiner-related effects were also observed for AL and GH. Correction values for pairwise combinations of probes were determined. CONCLUSIONS: We provided empirical evidence and quantified the effect of probe type on periodontal measurements. Differences in probe type should be considered when comparing periodontal data within and between epidemiological studies and appropriate corrections, provided here, should be applied.

A comparison of periodontal status in the two regional, population-based studies of SHIP and INVEST.

OBJECTIVES: To compare the prevalence of periodontal disease between two randomly selected population-based studies (the Oral Infections and Vascular Disease Epidemiology Study (INVEST) and the Study of Health in Pomerania (SHIP)) and address relevant methodological issues. METHODS: Comparison was restricted to 55- to 81-year olds. Attachment loss (AL), probing depth (PD) and tooth count were assessed in INVEST (full-mouth, six sites) and SHIP (half-mouth, four sites). Subjects were classified according to the CDC/AAP case definition. Recording protocols were standardized. Mixed linear or logistic models were used to compare INVEST with SHIP. RESULTS: Mean half-mouth AL was lower in INVEST versus SHIP (INVEST: 2.9 mm versus SHIP: 4.0 mm, p < 0.05). Findings were similar across multiple periodontal disease definitions. After equalization of recording protocols and adjustment for periodontal risk factors, mean AL and PD were 1.2 and 0.3 mm lower in INVEST versus SHIP (p < 0.001). The odds for severe periodontitis (CDC/AAP) was 0.2-fold in INVEST versus SHIP (p < 0.001). Confounding effects of age, gender, race/ethnicity, education and use of interdental care devices were highest as indicated by change-in-estimate for study. CONCLUSION: Implementation of the proposed method for comparison of epidemiological studies revealed that periodontitis was less prevalent in INVEST compared with SHIP, even after extensive risk-factor adjustment.