Overview of systematic reviews on periodontal-orthodontic interactions: A comprehensive literature analysis.

The aims of this research were to investigate the methodological quality of systematic reviews on periodontal-orthodontic interactions (i.e. reviews of primary research broadly defined as any including both periodontic and orthodontic components) and to provide a mapping of the researched topics. We searched four major databases (PubMed, Lilacs, Web of Science, and Embase) for systematic reviews of periodontal-orthodontic interactions. We used the AMSTAR-2 tool (the acronym is derived from 'a measurement tool to assess systematic reviews') to assess the methodological quality of the included systematic reviews. Individual AMSTAR-2 ratings were tabulated, and the percentage per item was calculated. To assess the association between the AMSTAR-2 percentage score and the overall confidence in the systematic review results, an ordinal regression model was used. We initially retrieved 973 documents, and 43 systematic reviews were included. Systematic reviews of interventions were the most prevalent (n = 26, 60.5%). Most of the systematic reviews did not report a meta-analysis (n = 25, 58.1%). In addition, most of the studies included in the systematic reviews had an unclear or high risk of bias. Most of the systematic reviews were rated as having critically low or low overall confidence (n = 34, 79.1%). A significant correlation was found between the AMSTAR-2 percentage score and overall confidence in the results. The methodological quality of systematic reviews on periodontal-orthodontic interactions can be improved. The limitations of our study include potential language bias and an arbitrary classification of the topics researched.

Impact of dental prosthetic treatment and patients' expectations on the seven domains and four-dimensional scale of the Oral Health Impact Profile.

BACKGROUND: Recently, recommendations were given for a new scoring of the Oral Health Impact Profile (OHIP). The original seven domain structure should be replaced by a four-dimensional scale. OBJECTIVES: To investigate the effect of dental prosthetic treatment on the seven domains and the four-dimensional scale of the OHIP-G49/53 questionnaire. METHODS: Seventy four patients were grouped according their pre- and post-treatment situation and the type of treatment they received. Patients completed the OHIP-G49/53 questionnaire before prosthetic treatment (T0), and at 1 week (T1), 3 months (T2) and 6 months (T3) after treatment. Treatment effects on the seven domains and the four dimensions of the OHIP scale were analysed, and the oral health-related quality of life (OHRQoL) was measured. Patients' expectations of their prosthetic treatment were also evaluated. Data were analysed using two-way Mixed ANOVA, regression analysis, and Cronbach's alpha test with a level of significance of α ≤ .017. RESULTS: OHRQoL significantly improved following prosthetic treatment compared with baseline. The largest improvement was found between T0 and T1 evaluations (all p ≤ .001). Unlike the seven-domain scale, the four OHIP dimensions demonstrated further significant improvements across the T1/T2/T3 evaluations (all p ≤ .017). Different pre-treatment findings had different treatment effects on the four OHIP dimensions and seven OHIP domains. Patients' expectations were mainly fulfilled. CONCLUSION: Compared with the seven-domain scale, the four dimensions showed significant follow-up changes, suggesting the four dimensions are suitable for evaluating treatment effects up to 6 months. Clinically meaningful effects of dental prosthetic treatment can be sensitively measured using the four-dimensional OHIP scale.

Immediate loading of dental implants in edentulous mandibles using Locator attachments or Dolder bars: A 9-year prospective randomized clinical study.

AIM: To evaluate the long-term survival, incidence of prosthetic/technical and biological complications and the oral-health-related quality of life in patients with an edentulous mandible who were fitted with overdentures on two immediately loaded implants in the symphyseal area. MATERIALS AND METHODS: Forty-six patients with edentulous mandibles received two immediately loaded implant-retained dentures with either two Locator attachments or egg-shaped bar attachments. Implant outcomes were recorded after a period of observation of 9 years and included prosthetic complications, modified gingiva index (mGI), modified plaque index (mPI), oral health impact profile (OHIP-G) and radiographic estimation of bone loss. RESULTS: In 2020/2021, 27 patients with 54 implants were still available for follow-up. In total, nine implants in six patients were lost. Survival was 89.1% in the bar group and 91.3% in the Locator group. Implant success was 84.6% in the Locator group and 76.9% in the bar group. The mPI values were significantly higher in the bar group than in the Locator group, whereas no difference was seen in the mGI values. During the observation period, 152 prosthetic complications occurred, but the OHIP-G score did not differ significantly. CONCLUSIONS: There was no difference in implant survival between Locator or joint bar attachments over a 9-year observation period. Joint bar attachments were associated with slightly more complications, while patients in the Locator group were able to maintain better oral hygiene. The study was registered in the German Register of Clinical (Trials DRKS00004245).

Mandibular advancement device: prescription in adult dental sleep medicine - guideline of the German Society of Dental Sleep Medicine.

PURPOSE: Obstructive sleep apnea (OSA) may result in severe health onditions, reduces quality of live, and affects high percentages of the adult population. Due to recent changes in the German health care regulations, mandibular advancement devices (MAD) will become available as a treatment option for OSA to a greater extent for general dentists and their patients. METHODS: A guideline development group consisting of nine members representing four German dental and medical organizations was formed, in order to provide critical information and orientation to the main stakeholders (dentists and patients), regarding the use of MAD for the treatment of OSA within dental sleep medicine. RESULTS: This guideline aims to inform physicians and dentists, particularly those with acquired qualification/specialization in sleep medicine (or in the diagnosis and treatment of sleep-related breathing disorders), as well as experts, payers, and patients. It delivers recommendations on technical requirements for MAD prescription and fabrication, clinical procedures, maintenance, and follow-up procedures. CONCLUSION: A MAD should be designed for long-term therapy and must be a custom made, adjustable, bimaxillary retained two-splint system equipped with adjustable protrusive elements. The fabrication in a dental laboratory should be based on dental impressions or scans and three-dimensional registrations of the starting position taken with a bite gauge.

Comparing efficacy of the mandibular advancement device after drug-induced sleep endoscopy and continuous positive airway pressure in patients with obstructive sleep apnea.

PURPOSE: The purpose of this study was to compare objective and self-reported outcomes of two treatments for managing mild, moderate, and severe obstructive sleep apnea (OSA) in adults: a mandibular advancement device (MAD) and continuous positive airway pressure (CPAP). METHODS: Patients diagnosed with OSA by means of polysomnography (PSG) included one group treated with a custom-made, two-piece, adjustable MAD and a second group treated with CPAP for 8 weeks. Before the initiation of the treatment, all patients assigned to MAD underwent drug-induced sleep endoscopy (DISE), and all CPAP group patients underwent manual titration of CPAP after PSG. Objective (PSG) and self-reported (Epworth Sleepiness Scale [ESS] and Short Form Health Survey [SF-36]) data were used to assess outcomes. Collected data included apnea-hypopnea index (AHI), mean capillary oxygen saturation (SpO2), oxygen desaturation index (ODI), arousal index (AI), degree of daytime sleepiness, and quality of life. A PSG follow-up after 8 weeks with MAD in situ, and data from the CPAP data card were used to assess the effect of the two treatments. RESULTS: A total of 59 patients included 30 treated with MAD and 29 treated with CPAP. Between baseline and the 8-week follow-up, the mean AHI score decreased significantly from 35.1 to 6.8 episodes/h (p < 0.001) in patients treated with MAD and from 35.2 to 3.0 episodes/h (p < 0.001) in patients treated with CPAP. The mean AHI score at the 8-week follow-up was significantly lower in CPAP group than in MAD group (p = 0.003). The two groups did not differ significantly at follow-up regarding SpO2 (p = 0.571), ODI (p = 0.273), AI (p = 0.100), ESS score (p = 0.648), and SF-36 score (p = 0.237). CONCLUSION: In the short term, patients on CPAP attained better PSG outcomes in terms of AHI reduction. Both MAD after DISE evaluation and CPAP resulted in similar improvements in clinical symptoms and health-related quality of life, even in patients with severe OSA.

Drug-induced sleep endoscopy improves intervention efficacy among patients treated for obstructive sleep apnea with a mandibular advancement device.

PURPOSE: To compare the short-term treatment effect of a mandibular advancement device (MAD) with and without previous drug-induced sleep endoscopy (DISE) on polysomnography (PSG) and other sleep apnea-related treatment outcomes (Short Form Health Survey [SF-36] and Epworth Sleepiness Scale [ESS]) among adults with mild, moderate, and severe obstructive sleep apnea (OSA). We hypothesized that using DISE would improve the efficacy of MADs on the sleep apnea parameters. METHODS: The study sample consisted of patients with OSA who were unable or unwilling to tolerate a CPAP device, divided into an experimental (with DISE) and a control (without DISE) group. RESULTS: Of 50 patients with OSA, 40 men (80%), mean age was 48.8 ± 12,3 years. The mean apnea-hypopnea index (AHI) score of both groups decreased significantly between baseline and the 8-week follow-up titration PSG with MAD in situ, from 31.7 ± 17.3 (mean ± SD) apnea-hypopnea episodes/h to 7.0 ± 6.4/h (p < 0.0001) in the experimental group, and from 22.5 ± 16.6 episodes/h to 11.4 ± 8.0/h (p < 0.024) in the control group. Capillary oxygen saturation (SpO2) levels did not change significantly between the two timepoints for either group. The SF-36 (p < 0.023) and ESS (p < 0.036) results of both groups improved significantly between baseline and the 8-week follow-up after starting MAD treatment; however, the improvement in quality of life was significantly more pronounced in the experimental group than in the control group (p < 0.0001). CONCLUSION: DISE provides a significant benefit to patients with OSA undergoing MAD treatment. It can be used as a valuable prediction tool in clinical practice for the management of patients with OSA, even those with moderate and severe disease.

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.

Diagnostic accuracy of the Diagnostic Criteria for Temporomandibular Disorders for children aged 8-12 years.

BACKGROUND AND OBJECTIVE: Objective of this study was to determine whether the diagnostic accuracy of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) is sufficient for use among schoolchildren aged 8-12 years. METHODS: This prospective cohort study on diagnostic accuracy with calibrated examiners was conducted among 533 children of both sexes aged 8-12 years, with and without TMD symptoms, selected randomly from the Rhein-Neckar district. Self-reporting of non-dental facial pain was used as the reference standard, against which we calculated the following for the pain-related items of the DC/TMD (index test): sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratio, accuracy and 95% Wilson Score confidence intervals. We also calculated the area under the receiver-operating characteristic (AUROC) curve displaying sensitivity and specificity. RESULTS: Our final sample consisted of 282 children, half of whom reported having facial pain and 3.2% reported sounds from the temporomandibular joints (TMJs). Despite high specificity (90.78%; 95% confidence interval (CI): [84.86%; 94.53%]), sensitivity of the adapted DC/TMD for pain on maximum jaw opening was poor (37.59%; 95% CI: [30.02%; 45.81%]). For pain on palpation, more similar values were recorded for sensitivity (74.47%; 95% CI: [66.69%; 80.95%]) and specificity (70.21%; 95% CI: [62.21%; 77.14%]). The diagnostic odds ratio was >1 for both examinations. The AUROC for pain on opening was 68.39% (95% CI: [62.62%; 74.16%]), and for pain on palpation, it was 74.63% (95% CI: [69.45%; 79.81%]), whereas the combination of both resulted to an AUROC of 74.09% (95% CI: [68.96%; 79.21%]). It was not possible to measure the diagnostic accuracy of the DC/TMD regarding TMJ sounds or jaw-opening limitations, as they occurred too rarely in our sample. CONCLUSION: In this study, the diagnostic accuracy of the DC/TMD for TMD-related pain in children was lower than that recorded for adults in previous studies.

Comparison of acupuncture on specific and non-specific points for the treatment of painful temporomandibular disorders: A randomised controlled trial.

BACKGROUND AND OBJECTIVE: The aim of this single-centre, two-arm, parallel-group, double-blinded, randomised controlled trial was to investigate the disputed specific effectiveness of acupuncture by comparing acupuncture on specific and non-specific points among patients with non-chronic, painful TMDs. METHODS: Following predefined eligibility criteria, 49 consecutive patients of both sexes were recruited to the study. All subjects were diagnosed with a non-chronic (Graded Chronic Pain Scale grade <3) painful TMD, as assessed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Patients were randomly assigned to group A (acupuncture on specific points) or group B (acupuncture on non-specific points) after the initial examination (T0). Both acupuncture treatment sessions were conducted by a trained dentist once a week for four weeks. The examination was repeated five weeks (T5) after T0 by one calibrated examiner who was unaware of the study groups. Characteristic pain intensity (CPI) was evaluated as the main outcome criterion and compared between times and treatment groups by means of non-parametric tests (significance level set at P = .05). Secondary outcomes comprised the maximum corrected active mouth-opening without pain (MAO); patients' expectations regarding acupuncture treatment and pain development; depressivity; and oral health-related quality of life (OHRQoL). RESULTS: A total of 41 patients (38 female) successfully completed the study (mean age: 40.17 ± 16.61). The two groups did not differ significantly at any time in terms of age and CPI. However, CPI was significantly (P < .05) lower at T5 than at T0 for both groups (29.66 and 30.35% lower in group A and group B, respectively). An increase in MAO was observed at T5 for both groups but was significant for group B only (P = .016). All patients had positive expectations of acupuncture therapy, and the two groups did not differ significantly at T5 with regard to the extent to which their expectations had been fulfilled by the treatment (P = .717). Comparison of T0 and T5 showed a statistically significant reduction of depressivity for group A (P = .0205), but no significant change for group B (P = .329). At T5, OHRQoL had improved significantly for both groups (group A, P = .018; group B, P < .001) compared with at T0. CONCLUSIONS: Acupuncture on both specific and non-specific points reduces the non-dysfunctional pain of TMD patients. The effect of acupuncture on painful TMD cannot be attributed to the specific point selection.

Consensus-based clinical guidelines for ambulatory electromyography and contingent electrical stimulation in sleep bruxism.

As yet, there are still no evidence-based clinical diagnostic and management guidelines for ambulatory single-channel EMG devices, like the BUTLER® GrindCare® (GrindCare), that are used in patients with sleep bruxism. Therefore, a consensus meeting was organised with GrindCare developers, researchers, and academic and non-academic clinicians experienced with the use of ambulatory EMG devices. The aim of the meeting was to discuss and develop recommendations for clinical guidelines for GrindCare usage, based on the existing clinical and research experience of the consensus meeting's participants. As an important outcome of the consensus meeting, clinical guidelines were proposed in which an initial 2-week baseline phase with the device in its inactive (non-stimulus) mode for habituation and assessment of the number of jaw-muscle activities is followed by a 4-week active phase with contingent electrical stimuli suppressing the jaw-muscle activities. As to avoid the commonly reported reduction in sensitivity to the stimuli, a 2-week inactive phase is subsequently installed, followed by a repetition of active and inactive phases until a lasting reduction in the number of jaw-muscle activities and/or associated complaints has been achieved. This proposal has the characteristics of a single-patient clinical trial. From a research point of view, adoption of this approach by large numbers of GrindCare users creates a great opportunity to recruit relatively large numbers of study participants that follow the same protocol.

Systematic reviews in orthodontics: Impact of the PRISMA for Abstracts checklist on completeness of reporting.

INTRODUCTION: This study evaluated and compared the completeness of reporting of abstracts of orthodontics systematic reviews before and after the publication of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Abstracts Checklist (PRISMA-A). METHODS: Abstracts of systematic reviews and meta-analyses in orthodontics published in PubMed, Latin American and Caribbean Health Sciences Literature, and the Cochrane Database of Systematic Reviews databases before March 23, 2018, that met the predefined inclusion and exclusion criteria, were evaluated using the 12 items of PRISMA-A, scoring each item from 0 to 2. Abstracts were classified into 2 groups: before and after publication of the PRISMA-A checklist. Three calibrated evaluators (intraclass correlation coefficient and kappa > 0.8) assessed the scores for compliance with the checklist. The number of authors, country of affiliation of the first author, performance of meta-analysis, and topic of the article were recorded. A regression analysis was performed to assess the associations between abstract characteristics and the PRISMA-A scores. RESULTS: Of 1034 abstracts evaluated, 389 were included in the analysis. The mean PRISMA-A score was 53.39 (95% CI, 51.83-54.96). The overall score for studies published after the publication of the checklist was significantly higher than for studies published before (P ≤ 0.0001). The components returning significantly higher scores after publication of PRISMA-A were title (P = 0.024), information from databases (P = 0.026), risk of bias (P ≤ 0.0001), included studies (P ≤ 0.0001), synthesis of results (P ≤ 0.0001), interpretation of results (P = 0.035), financing and conflict of interest (P ≤ 0.0001), and registration (P ≤ 0.0001). These results showed the positive effect of PRISMA-A had on the quality of reporting of orthodontics systematic reviews. Nevertheless, the poor adherence revealed that there is still need for improvement in the quality of abstract reporting. CONCLUSIONS: The quality of reporting of abstracts of orthodontic systematic reviews and meta-analyses increased after the introduction of PRISMA-A.

Adaptation to new complete dentures-is the neuromuscular system outcome-oriented or effort-oriented?

OBJECTIVE: The aim of this study was to observe the adaptation strategy of the stomatognathic system during the adaptation of complete dentures, comprising masticatory parameters and subjective measures. Our hypothesis was that with new dentures, masticatory performance would increase while the effort of the system is kept constant. MATERIAL AND METHODS: Thirty-two patients received standardized new complete dentures. Masticatory performance tests were conducted with old dentures (T1), immediately after incorporation of new dentures (T2) and after an adaptation period of 3 months (T3). Patients habitually chewed the silicone-based artificial test food Optocal. The comminuted test food was analyzed and mean particle sizes (x50) were calculated. Simultaneously, surface EMGs of the anterior temporalis and masseter muscles were recorded. Specific (SMW) and total muscle work (TMW) were determined. Patients filled in the OHIP-49 questionnaire. Test conditions were compared using repeated-measures ANOVA with SPSS 22 (SPSS Inc.) RESULTS: Masticatory performance increased (P = 0.016) between old (x50 = 4.99 ± 0.28) and adapted new dentures (x50 = 4.80 ± 0.33). TMW deteriorated (P = 0.004) at T2 (from TMW1 = 119.77 ± 56.49 to TMW2 = 92.12 46.27), and increased again (P = 0.028) at T3 (TMW3 = 107.66 ± 44.65). OHIP scores decreased significantly in all subscales (P < 0.001…P = 0.046); the total score was reduced (P < 0.001) from 56.24 ± 29.05 (T1) to 34.66 ± 24.74 (T3). CONCLUSION: In complete denture wearers, masticatory performance improves over an adaptation period. Muscle work initially decreased before reaching its original level again after adaptation. Subjective parameters overestimated the functional improvements. CLINICAL SIGNIFICANCE: The subjective evaluation does not adequately reflect functional improvements. The assessment of function requires an adaptation period.

Functional adaptation of the masticatory system to implant-supported mandibular overdentures.

OBJECTIVES: The purpose of this study was to investigate the adaptation behavior of the stomatognathic system after immediate loading (24 to 72 h after surgery) of two implants supporting mandibular overdentures, assessed on insertion and three months later. The study hypothesis was that insertion of the overdentures would significantly change masticatory performance and muscle activity at both times. MATERIAL AND METHODS: Thirty subjects (nine female, mean age 69.64 ± 11.81 years; 21 male, mean age 68.67 ± 7.41 years) who participated in a randomized clinical trial were included in the study. Each patient was examined three times: (i) at baseline, after already having worn new dentures for three months (T1); (ii) immediately after insertion of the overdentures on the implants (T2); and (iii) after an adaptation period of three months (T3). Examination comprised assessment of masticatory performance with artificial test food (Optocal), and simultaneous bilateral surface EMG recording of the masseter and anterior temporalis muscles. Particle-size distribution (representative value X50 ), maximum muscle contraction (MVC), and total muscle work (TMW; area under the curve) were compared by use of repeated-measures analysis of variance (ANOVA). RESULTS: At T3, all measured variables (i.e., masticatory performance and muscle activity) were significantly different from those at T1. At T2, no significant changes were observed. The study hypothesis had to be rejected for T2 but accepted for T3. CONCLUSION: Functional rehabilitation (in terms of masticatory performance and masticatory muscle activity) does not occur immediately after immediate loading of two implants with mandibular overdentures, but requires a significant time for functional improvement.

Patients' Values in Clinical Decision-Making.

OBJECTIVE: Shared decision-making involves the participation of patient and dental practitioner. Well-informed decision-making requires that both parties understand important concepts that may influence the decision. This fourth article in a series of 4 aims to discuss the importance of patients' values when a clinical decision is made. METHODS: We report on how to incorporate important concepts for well-informed, shared decision-making. Here, we present patient values as an important issue, in addition to previously established topics such as the risk of bias of a study, cost-effectiveness of treatment approaches, and a comparison of therapeutic benefit with potential side effects. RESULTS: We provide 2 clinical examples and suggestions for a decision tree, based on the available evidence. CONCLUSION: The information reported in this article may improve the relationship between patient and dental practitioner, resulting in more well-informed clinical decisions.

Effect of Causative Tooth Extraction on Clinical and Biological Parameters of Odontogenic Infection: A Prospective Clinical Trial.

PURPOSE: To prospectively compare changes of body temperature, white blood cell count, fibrinogen, and C-reactive protein between odontogenic infections in which the responsible tooth was removed and odontogenic infections in which the treatment included no extraction. MATERIALS AND METHODS: The sample was composed of patients admitted to the authors' maxillofacial unit for odontogenic infection from 2010 through 2013. One hundred seventy-nine patients were categorized into an extraction or a non-extraction group based on whether the causative tooth was non-restorable or restorable, respectively. Non-restorable teeth were extracted at admission of the patient. Otherwise, the treatment protocol, including incision of the involved space in conjunction with intravenous antibiotics, was the same for the 2 groups. The parameters were measured and recorded at admission and 2 days later. Data records were statistically analyzed by comparing the change of the parameters studied between the extraction and non-extraction groups. P values less than .05 were regarded as statistically significant. RESULTS: One hundred seventy-nine patients fulfilled the inclusion criteria and were enrolled in the study. The mean age of the patients was 39.1 years (minimum, 14 yr; maximum, 81 yr; standard deviation, 15.4 yr). One hundred nine patients (60.9%) were male, and 70 (39.1%) were female. Differences in the mean decrease of axillary temperature, white blood cell count, fibrinogven, and C-reactive protein between the 2 groups were 0.178, 2,300, 1.01, and 0.64, respectively. All these differences were statistically significant (P =.02, .001, .001, and .001, respectively). Also, the mean hospital stay in the extraction group was 1.05 days shorter than in the non-extraction group, with the difference being statistically significant (P = .006). CONCLUSIONS: In odontogenic maxillofacial infections, extraction of the causative tooth is associated with a faster clinical and biological resolution of the infection.

Particle size distributions determined by optical scanning and by sieving in the assessment of masticatory performance of complete denture wearers.

OBJECTIVES: Standard procedure for the measurement of masticatory performance is the fractionated sieving of fragmented test food, which is substantially time consuming. The aim of this study was to introduce a less laborious, comparable, and valid technique based on scanning. METHODS: Fifty-six Optocal chewing samples were minced by wearers of complete dentures with 15 and 40 chewing strokes and analyzed by both a sieving and a scanning method. The sieving procedure was carried out using ten sieves (5.6, 4.0, 2.8, 2.0, 1.4, 1.0, 0.71, 0.5, 0.355, and 0.25 mm) and measuring the weight of the specific fractions. Scanning was performed with a flatbed scanner (Epson Expression1600Pro, Seiko Epson Corporation, Japan, 1,200 dpi). Scanned images underwent image analysis (ImageJ 1.42q, NIH, USA), which yielded descriptive parameters for each particle. Out of the 2D image, a volume was estimated for each particle. In order to receive a discrete particle size distribution, area-volume-conversion factors were determined. The cumulated weights yielded by either method were curve fitted with the Rosin-Rammler distribution (MATLAB, The MathWorks, Inc., Natick, USA) to determine the median particle size X 50. RESULTS: The Rosin-Rammler distributions for sieving and scanning resembled each other and showed an excellent correlation in 15/40 chewing strokes (r = 0.995/r = 0.971, P < 0.01, Pearson's correlation coefficient). The median particle sizes varied between 4.77/3.04 and 5.36/5.28 mm (mean 5.07/4.67) for scanning and 4.69/2.39 and 5.23/5.43 mm (mean 5.03/4.57) for sieving. On average, scanning overestimated the X 50 values by 1/2.4 %. The scanning method took 10 min per sample in contrast to 50 min for sieving. CONCLUSION: Optical scanning is a valid method comparable to sieving. CLINICAL RELEVANCE: The described method is feasible and appropriate for the measurement of masticatory performance of denture wearers.

An economic evaluation of maxillary implant overdentures based on six vs. four implants.

BACKGROUND: The purpose of the present study was to assess the value for money achieved by bar-retained implant overdentures based on six implants compared with four implants as treatment alternatives for the edentulous maxilla. METHODS: A Markov decision tree model was constructed and populated with parameter estimates for implant and denture failure as well as patient-centred health outcomes as available from recent literature. The decision scenario was modelled within a ten year time horizon and relied on cost reimbursement regulations of the German health care system. The cost-effectiveness threshold was identified above which the six-implant solution is preferable over the four-implant solution. Uncertainties regarding input parameters were incorporated via one-way and probabilistic sensitivity analysis based on Monte-Carlo simulation. RESULTS: Within a base case scenario of average treatment complexity, the cost-effectiveness threshold was identified to be 17,564 € per year of denture satisfaction gained above of which the alternative with six implants is preferable over treatment including four implants. Sensitivity analysis yielded that, depending on the specification of model input parameters such as patients' denture satisfaction, the respective cost-effectiveness threshold varies substantially. CONCLUSIONS: The results of the present study suggest that bar-retained maxillary overdentures based on six implants provide better patient satisfaction than bar-retained overdentures based on four implants but are considerably more expensive. Final judgements about value for money require more comprehensive clinical evidence including patient-centred health outcomes.

Critical appraisal of systematic reviews on the effect of a history of periodontitis on dental implant loss.

OBJECTIVE: To perform a systematic critical appraisal of the methodological quality of systematic reviews on the effect of a history of periodontitis on dental implant loss. MATERIALS & METHODS: PubMed, the Cochrane database for systematic reviews, the DARE, Biosis Preview, CINAHL, Web of Science, and LILACS electronic databases were searched on 16th June 2012, independently and in duplicate, for systematic reviews and meta-analyses related to dental implants for patients with and without a history of periodontitis. Manual searching of the reference lists of included papers was also conducted. The methodological quality of these systematic reviews was assessed by use of the AMSTAR and R-AMSTAR checklists. Before quality assessment was initiated, the reviewers were calibrated until they achieved excellent agreement. RESULTS: Sixty-eight papers were initially retrieved. Of these, nine systematic reviews and three meta-analyses were included. Some domains, for example, "characteristics of the included studies" were satisfied in both checklists. In contrast, domains such as "comprehensive literature search" and "assessment of likelihood of publication bias" were rarely met. CONCLUSION: Much methodological variability was encountered in the selected reviews. To furnish readers with a more comprehensive assessment of the evidence, authors should observe higher standards when conducting and reporting their reviews.

Neuromuscular interaction of jaw and neck muscles during jaw clenching.

AIMS: To test the hypothesis that jaw muscles and specific neck muscles, ie, levator scapulae, trapezius, sternocleidomastoideus, and splenius capitis, co-contract at the different submaximum bite forces usually generated during jaw clenching and tooth grinding, and for different bite force directions. METHODS: Bite-force transducers that measured all three spatial force components were incorporated in 11 healthy subjects. The test persons developed feedback-controlled submaximum bite forces in a variety of bite-force directions. The electromyographic (EMG) activity of the levator scapulae, splenius capitis, and trapezius muscles was recorded, at the level of the fifth cervical vertebra, by use of intramuscular wire electrodes. The activity of the sternocleidomastoideus and masseter muscles was recorded by surface electrodes. For normalization of the EMG data, maximum-effort tasks of the neck muscles were conducted in eight different loading directions by means of a special force-transducer system. Differences between neck-muscle activity during chewing, maximum biting in intercuspation, and the force-controlled motor tasks were compared with the baseline activity of the various muscles by one-way repeated-measures analysis of variance. RESULTS: The results confirmed the hypothesis. Co-contractions of the neck muscles in the range of 3% to 10% of maximum voluntary contraction were observed. Significant (P < .05) activity differences were recorded as a result of the different force levels and force directions exerted by the jaw muscles. Long-lasting action potential trains of single motor units triggered by jaw clenching tasks were also detected. CONCLUSION: The findings support the assumption of a relationship between jaw clenching and the neck muscle activity investigated. The low level of co-contraction activity, however, requires further study to elucidate possible pathophysiological interactions at the level of single motor units.

A new instrument for assessing the quality of studies on prevalence.

There are numerous scientific articles of studies on the prevalence of disorders with non-standardised examination and diagnostic protocols. Because their quality is heterogeneous, a new instrument has been developed for the assessment of such studies. The new instrument is based mainly on statistical criteria. The points assigned for each of the main criteria according to the information gained from each paper are summed up to form a Total Quality Score (TQS). The interrater reliability of the instrument was tested by employing Kappa and Interrater Correlation Coefficient (ICC) statistics. The latter was assessed on the results of three independent investigators. The new quality instrument appeared to be easy to use, and the instructions were comprehensible. The ICC((2,1)) for the TQS ranged between 0.94 and 1.00 indicating almost perfect agreement between the investigators. The reliability of the new instrument enables its use for scientific review purposes. In this way, its validity will also be tested. The instrument could be adopted for assessment of scientific articles of studies on the prevalence of disorders in many, similar, scientific areas.