Studies of mandibular movements in speech

A method of transducing mandibular movements in speech using synchro-transmitters is described.

Incisal occlusion was shown to have an important part to play in the amount and direction of jaw movement.

Mandibular positions were shown to be precise and repeatable, especially for the ‘s’ sound. Insertion of intra-oral appliances of varying dimensions did not have a significant effect on this positional precision. It is anticipated that the precision of vertical dimension determination during full denture construction will not be influenced by the dimensions of the intra-oral appliances.     

A cephalometric comparison of normal weight and obese subjects with obstructive sleep apnoea

Purpose: To compare the skeletal, oropharyngeal and soft tissue features of two groups of subjects with obstructive sleep apnoea (OSA) using lateral cephalometric radiographs. One group of subjects exhibited a normal body mass index, whilst the other was obese.Methods: Lateral cephalometric radiographs of 48 dentate, white, Caucasian males with confirmed OSA were traced and digitized and comparisons were sought between the skeletal and oropharyngeal morphologies of the two groups. Twenty-eight subjects were obese and 20 individuals exhibited normal body mass indices (BMI). Mann–Whitney U-tests were employed to examine differences between the two groups and a P value of less than 0.05 was considered significant.Results: Subjects with a normal BMI exhibited significantly more retruded maxillae, more upright incisors, smaller mandibles and a shorter distance between the lower incisor and the posterior pharyngeal wall than obese subjects. In the latter group, the length of the lower face was increased. In addition, the lengths and cross-sectional areas of both the soft palate and tongue were significantly larger. The hyoid was further away from both the chin (menton) and the cervical column (C3) in this group. No differences were found in minimum airway dimensions or in the cross-sectional area of the oropharynx between the groups although, as expected, these dimensions were reduced in comparison with control values.Conclusions: Obstructive sleep apnoea subjects of normal weight have more anterior–posterior dentofacial abnormalities than their obese counterparts. However, both groups are clearly distinguishable from control individuals. In the obese subjects, additional soft tissue anomalies are found. It would therefore seem that all OSA subjects exhibit some anatomical basis for their condition, but this is compounded by soft tissue factors in obese individuals. It is therefore doubtful whether loss of weight in obese subjects would significantly influence the severity of the condition.     

Bone Healing after Tooth Extraction with or without an Intervention: A Systematic Review of Randomized Controlled Trials

Objectives: To assess whether the use of a graft and/or membrane post‐tooth extraction improves healing of the site dimensionally, radiographically, and/or histologically. Materials and Methods: MEDLINE and EMBASE and the Cochrane Central register of controlled trials (CENTRAL) were searched up until August 2011. Randomized controlled trials that included and compared healing post‐tooth extraction between a control (no intervention) and a graft and/or membrane (test) were selected. Results: Titles and abstracts of 2,861 papers were screened. A total of 42 papers were selected for full text reading. Nine papers met the eligibility criteria and were selected for further analysis. Because of the varying graft materials used and the different methods of investigation, as well as the variation in follow‐up times, a meta‐analysis was not possible. The present review found that clinically, there was a range in loss of width in the control sites of 2.46 mm (SD 0.4 mm) to 4.56 mm (SD 0.33 mm) compared to 1.14 mm (SD 0.87 mm) to 2.5 mm (SD 1.2 mm) in the test sites. The range in loss of height in control sites was 0.9 mm (SD 1.6 mm) to 3.6 mm (SD 1.5 mm) compared to a gain of 1.3 mm (SD 2 mm) to a loss of 0.62 mm (SD 0.51 mm) in test sites. Radiographically a range of change in bone height of between 0.51 mm (No SD) to 1.17 mm (SD 1.23 mm) was noted in control sites compared to a change of between 0.02 mm (SD 1.2 mm) and 1 mm (SD 1.4 mm) in test sites. Conclusion: There is limited data regarding the effectiveness of alveolar ridge preservation therapies when compared to the control. Overall the socket intervention therapies did reduce alveolar ridge dimensional changes post‐extraction, but were unable to prevent resorption. Histology did demonstrate a large proportion of residual graft material that may account for some of the difference in alveolar ridge dimensions at follow up.     

Attitudes of dentists, working in Riyadh, toward people with a sensory impairment

This study was conducted to determine the attitudes of dentists, working in Riyadh, toward people with a sensory impairment (SI), according to the Scale of Attitude Towards Disabled Persons (SADP). The SADP scale was modified to focus solely upon sensory impairment. The modified scale was pre-tested and then incorporated into a self-administered questionnaire. This was then administered to 600 dentists (response rate, 73.7%) working in the city of Riyadh, Saudi Arabia. The modified scale showed itself to be reliable, with a Chronbach's coefficient α 0.616 and four-factor analysis, which accounted for 38.5% of the variance. Ninety-four percent of the dentists were generally positive toward SI in the society. There were, however, significant variations in attitudes, with a more positive score for dentists who had worked for 30 years or more ( p ± 0.005), were specialists ( p < 0.005), received little or no undergraduate training in this subject ( p < 0.05), and who received their undergraduate training in Europe/North America ( p < 0.001). However, in a stepwise regression model, all these variables were significant except for the years of practice. The modified SADP showed dentists, working in Saudi Arabia, having a positive attitude toward people with SI.     

The Effects of Abutment Wall Height, Platform Size, and Screw Access Channel Filling Method on Resistance to Dislodgement of Cement-Retained, Implant-Supported Restorations

PURPOSE: Factors affecting the retention of fixed prostheses to natural abutments are well understood. In contrast, little is known concerning factors influencing the retention of fixed prostheses cemented to implant abutments. The purpose of this study was to investigate the effect that varying implant abutment wall height, platform size, and screw access channel filling method has on the retention of castings cemented to implant abutments using TempBond. MATERIALS AND METHODS: Four 15 degrees preangled abutments (Nobel Biocare Replace Select Esthetic) of each platform size--narrow (NP), regular (RP), and wide (WP)--were used. In each group of abutments the screw access axial wall was either unadjusted, one-third removed, two-thirds removed, or completely removed. The screw access channels were either fully or partially filled with Memosil, a vinyl polysiloxane impression material. For each abutment a casting was constructed that incorporated an attachment to allow removal. Castings were cemented to abutments with TempBond. The tensile force required to separate the cemented castings from the abutments was measured using an Instron Universal load-testing machine. RESULTS: The mean peak removal force for comparable abutments was significantly different ( p < 0.05): (1) where the screw access channel was completely filled with Memosil compared with those partially filled with Memosil; (2) with platform sizes--WP > RP > NP; (3) with alteration of axial wall height--1/3 removed > unadjusted = 2/3 removed > total wall removal. CONCLUSIONS: The retention of castings cemented to implant abutments with TempBond is influenced by the wall height, platform size, and the filling modality of the screw access channel.     

The mandibular pain dysfunction syndrome: an assessment of its treatment

Almost all clinicians claim successful results with their treatment of the mandibular pain dysfunction (MPD) syndrome, but longer term follow-up studies are relatively few. One hundred and nine patients whose treatment had been completed some time previously replied to a postal questionnaire which enquired into their experience of pain, limitation of jaw opening, clicks and evenness of ‘bite’. The results indicated that many patients experienced a return of discomfort, and clicking of the joints responded poorly to treatment. Limitation of jaw opening, on the other hand, showed a successful response to treatment.     

Reduction of left ventricular outflow tract obstruction with transcatheter mitral valve repair

Many patients with severe mitral regurgitation cannot undergo conventional mitral valve surgery due to prohibitive surgical risk and are candidates for transcatheter repair with an edge‐to‐edge technique. Prior reports suggest efficacy with this approach for mitral regurgitation due to hypertrophic cardiomyopathy with left ventricular outflow obstruction. We present a case report of transcatheter mitral valve repair for posterior leaflet prolapse with concomitant left ventricular outflow tract obstruction due to systolic anterior motion of the mitral valve in the absence of hypertrophic cardiomyopathy.