Hyoid bone position after surgical mandibular advancement

A cephalometric evaluation of the changes in the horizontal and vertical placement of the hyoid bone and of those in the position of the head over the cervical spine after surgical mandibular advancement was undertaken. Seven linear and one angular measurement were investigated in 60 patients, 17 males and 43 females, before and one year after surgical mandibular advancement. The hyoid bone moved forwards horizontally in 78 per cent of the subjects, backwards in 17 per cent, and in 5 per cent of patients it retained its pre-operative position. It moved vertically downwards in 32 per cent of subjects, and in 63 per cent it moved upwards and closer to the body of mandible. The amount of horizontal and vertical change of the hyoid bone was associated with the corresponding change of the mandible after surgery. The vertical change was more distinct in females compared with males. There was variation in the position of the head over the cervical spine; it showed extension in 26.7 per cent of the sample, flexion in 71.7 per cent, and remained the same in only 1.6 per cent after surgery. The results show that with surgical mandibular advancement the hyoid bone follows mainly the advancement of the mandible and moves closer to the body of the mandible. However, there are variations in the changes of hyoid bone and head position that are difficult to predict.     

Pain perception and utility: a comparison of the syringe and computerized local injection techniques

Thirty patients received maxillary infiltration and mandibular inferior alveolar nerve block injections with both a traditional syringe and a computerized system, the Wand. Patients noted their preference for either system and rated their injection pain and postoperative discomfort on a ten-point scale for each type of injection. Mean injection discomfort ratings with the Wand were lower than with the syringe but were not statistically significant. Reduced postoperative discomfort using the Wand for the inferior alveolar nerve block was significant. Both of the dentists in the study and those patients who stated a preference favored the Wand system.     

Effectiveness and dentin bond strengths of two materials for reinforcing thin-walled roots.

OBJECTIVES: To investigate the effectiveness of two restorative materials for reinforcing thin-walled roots and their microtensile bond strengths to root canal dentin. METHODS: Twenty-one decoronated maxillary central incisor roots were root filled and the canals enlarged to leave approximately 1.0 mm thick dentin walls. The roots were distributed randomly to three equal groups. Group 1 (control): a large tapered cast post-core was fabricated. Group 2 (BIS-CORE): a thick layer of dual-cured composite was placed in the post-hole before fabrication of a small-diameter tapered cast post-core. Group 3 (ChemFil Superior): a thick layer of glass-ionomer was placed, as before. Metal-ceramic crowns were fabricated for all teeth. Microtensile bond strength tests and optical and atomic force microscope observations were employed to examine adhesion between the two restorative materials and the root canal dentin. RESULTS: Mechanical loading (kN) demonstrated that composite 0.64 (S.D. 0.05), but not glass-ionomer 0.49 (0.05), significantly reinforced the fracture resistance of thin-walled roots, P<0.001. Microtensile bond strengths (MPa) were 21.7 (1.6) for composite and 12.9 (1.7) for glass-ionomer, P=002. SIGNIFICANCE: A thick intermediate layer of resin-bonded composite, sandwiched between the root dentin and a small-diameter cast Ni-Cr post or dowel, increased significantly the fracture resistance of the roots.     

Evaluation of tongue coating indices

AIM: The purpose of this study was to determine inter-examiner reproducibility of two modified Winkel tongue coating indices and to study the relationship between each of these two indices and the amount of tongue coating as determined by wet weight of scrapings from the dorsum of the tongue. MATERIALS AND METHODS: Twenty-five participants were selected for the study from among dental students. The selection was made to assure that a wide range of degrees of tongue coating were represented. Two independent examiners scored the tongue coatings using the two modified Winkel tongue coating indices (mWTCI 1 + 2 and mWTCI 2). After completion of index recordings, tongue scrapings were performed by one of the examiners. RESULTS: Inter-examiner reproducibility of mWTCI 1 + 2 and mWTCI 2 using Pearson's coefficients of correlation amounted to r = 0.48 and 0.93 respectively. Overall, mWTCI 2 showed higher correlations to wet weight of tongue scrapings than mWTCI 1 + 2. CONCLUSION: The mWTCI 2 was found to be highly reproducible and also valid as related to wet weight of tongue scrapings. This index would seem suitable for further studies on tongue coatings; effect of tongue cleaning; and rate of reformation of coatings after cleaning.     

Recovery of Enterococcus faecalis from cheese in the oral cavity of healthy subjects

INTRODUCTION: Enterococci are rarely found in the healthy human oral cavity, yet they are strongly associated with filled root canals. The origin of these enterococci remains unknown. Our hypothesis is that they are transient food-born colonizers under healthy conditions. This pilot study reinvestigated the prevalence of enterococci in the oral cavity of healthy volunteers, screened cheese samples for enterococci and investigated colonization of the oral cavity after ingestion of an enterocci-positive cheese. METHOD: Concentrated oral rinse samples were collected from a cohort of 50 dental students and proved negative for viable enterococci. Twenty cheese samples were obtained from local supermarkets. Enterococci were cultured and identified using standard methods. RESULTS: Viable enterococci were detected in one of five specimens of Swiss Tilsiter, three of five samples of French soft cheese, one of five Mozzarella samples and one of five Feta samples. Eight volunteers from the cohort consumed 10 g of a cheese with high Enterococcus faecalis load. Oral rinse samples were collected before and 1, 10 and 100 min after cheese ingestion. One minute after ingestion, a median of 5,480 E. faecalis colony-forming units was recovered from the oral rinse samples. Bacterial counts were reduced after 10 min, had dropped after 100 min to levels that were significantly (P < 0.005) different from the 1-min and 10-min scores and were below the detection limit after 1 week. CONCLUSIONS: These findings suggest that colonization of the healthy oral cavity by enterococci is transitional, but at the same time add weight to our hypothesis that enterococcal root canal infections could be food-borne.     

Serum markers of chronic dehydration are associated with saliva spinability

Findings of a relationship between saliva and dehydration have been observed, but the precise nature of these relationships is unclear and no evidence of a direct link has been found. In particular, no study reports a relationship between chronic dehydration and saliva conditions in community-dwelling older adults. This study aimed to identify whether salivary conditions are sensitive to body hydration markers in an elderly population. A total of 403 subjects aged 76 years participated in the study. Stimulated saliva flow rate and spinability of saliva were measured. In addition, determinations of serum levels of uric acid, blood urea nitrogen (BUN), creatinine, sodium and potassium were made. Dehydration was defined as uric acid >/= 7 mg dL(-1) according to the standard value. The salivary spinability were significantly associated with the concentration of uric acid (OR=2.06, P=0.044) according to multiple logistic regression analysis. In addition, after adjusting for gender, the uric acid concentration and the salivary spinability was significantly associated with BUN, potassium and creatinine levels. The subjects with high uric acid levels (>/= 7 mg dL(-1)) had the most elastic saliva. Both BUN and serum creatinine are the most commonly used indicators of renal function. Therefore, our findings might demonstrate that older adults who are dehydrated showed highly elastic saliva, which was associated with renal function. In conclusion, this study suggests that there is a significant relationship between chronic dehydration status and salivary spinability level.     

Occlusal measurement method can affect SEMG activity during occlusion

Summary Occlusal indicators are widely used in dental treatment to measure tooth contacts that occur during occlusion. However, the presence of an indicator may affect the mechanics of occlusion and lead to invalid tooth contact data. The objective of this study was to determine the effect of four indicators (Parkell, silk, T‐Scan^® sensor and paper) on surface electromyography (SEMG) activity during occlusion. Twenty‐three subjects performed strong bites and maximum clenches onto the four indicators and natural dentition. Surface electromyography recordings of anterior temporalis and superficial masseter activity and the subjects’ perception of each indicator were measured. SEMG activity with the T‐Scan^® sensor and paper was significantly different (higher masseter activity; P < 0·05) compared to that for natural dentition. The Parkell and silk gave no significant differences to natural dentition. Similarly, subjects perceived that T‐Scan^® sensor and paper had the greatest effect on occlusion and were the least comfortable (P < 0·05). Thus, the very plastic T‐Scan^® sensor and very thick articulating paper both affected SEMG activity during occlusion and, therefore, may not provide valid tooth contact information for dental treatment. In conclusion, occlusal indicators can change SEMG activity during occlusion which may affect the validity of the measurements they provide.     

Endoscopic periradicular surgery: a prospective clinical study

We did apicectomies of 30 teeth with periradicular lesions in 23 patients, using a 3 mm endoscope. Two patients failed to attend for postoperative assessment and of the remaining 21 patients who had 28 teeth treated the operation was judged after 1 year to be a success in 26 (93%).