Lack of effect of chlorhexidine varnish on Streptococcus mutans transmission and caries in mothers and children

In a randomized clinical trial, we evaluated the effect of a 10% chlorhexidine varnish (Chlorzoin) on the mother-child transmission of Streptococcus mutans and on subsequent caries experience. Chlorhexidine (n = 38) or a placebo varnish (n = 37) was applied to the dentitions of 75 mothers at a time when their first babies were about 6 months old (approximate time of first tooth emergence). Three more applications at weekly intervals and subsequent applications at 6-month intervals followed the initial application. The mother-child pairs were followed up until the child's fourth birthday. Maternal salivary S. mutans levels in the treatment group remained significantly lower (p < 0.05) compared to the control group up to 12 months after the initial application. However, this intervention did not significantly alter the S. mutans colonization in children or the caries increment in either the mother or the child.     

Physiological properties of periodontal mechanosensitive neurones in the posteromedial ventral nucleus of rat thalamus

Unitary discharges of periodontal mechanosensitive (PM) neurones responding to mechanical tooth stimulation were recorded from the posteromedial ventral nucleus (VPM) of rat thalamus. PM neurones are distributed in the ventromedial area in the rostral two-thirds of the VPM nucleus. Maxillary and mandibular tooth-sensitive neurones are arranged in dorsoventral sequence. Of the PM neurones, 36% were slowly adapting to pressure applied to the tooth and 67% were rapidly adapting. The majority of PM units were sensitive to the contralateral incisor tooth. Response magnitudes of the slowly adapting neurones varied with stimulus direction and were directionally selective to mechanical tooth stimulation. The optimal stimulus direction was labiolingual or linguolabial. Rapidly adapting neurones were directionally non-selective to tooth stimulation. The threshold for mechanical stimulation was <0.05 N. Mean response latencies evoked by electrical stimulation of the peripheral receptive fields were 4.6 ms in the slowly adapting neurones and 5.8 ms in the rapidly adapting neurones.     

A simple model to demonstrate the electronic apex locator

AIM: To describe and evaluate a newly developed model for demonstrating and teaching the use of electronic apex locators. SUMMARY: A phantom model, master jaw model and extracted human teeth were used to construct the demonstration model with alginate impression material as the periapical conductive medium. The model was validated in a series of length determinations with apical foramina enlarged to 0.20, 0.30 and 0.45 mm diameter, and the stability of the model was evaluated up to 45 h after construction. All evaluations were conducted with the Root ZX apex locator with 2.65 and 5.25% NaOCl in the canals. Most length measurements were within 1 mm of actual root length (range: -2.2 to +0.21 mm) and did not change significantly over 45 h for teeth with foramina of 0.3 mm or less. Measurements for teeth with wide (0.45 mm) apices were stable up to 28 h. NaOCl concentration did not significantly affect the readings. KEY LEARNING POINTS: A simple, inexpensive model can be manufactured from plastic dental jaws, natural teeth and alginate impression material to demonstrate electronic working length measurement. The model is stable for many hours and provides consistent results with different concentrations of NaOCl in the canal and various apical diameters. The model is a useful teaching aid but needs further evaluation and refinement before use in research applications.     

MMP-9 activation by tumor trypsin-2 enhances in vivo invasion of human tongue carcinoma cells

Various human cancer cells express tumor-associated trypsinogen-2 (TAT-2), which can efficiently activate matrix metalloproteinases (MMPs) in vitro. MMP-2 and MMP-9 are particularly associated with the invasive malignant potential of several tumors. To investigate the role of TAT-2 in tumor invasion, we overexpressed TAT-2 in two malignant human squamous cell carcinoma cell lines of tongue and in non-malignant human papilloma virus transformed gingival keratinocytes. The TAT-2 overexpression significantly increased the levels of active MMP-9 in the most malignant cell line. TAT-2-transfected cells intravasated (invaded blood vessels) up to 60% more efficiently than did the control cells in an in vivo chick embryo chorioallantoic membrane invasion model. This increased intravasation was almost completely abolished by a specific tumor-associated trypsin inhibitor (TATI). These results indicate that TAT-2 has a role in the invasive growth of tumors, either alone or in cascade with gelatinases, especially by generating active MMP-9.     

Effects of low-intensity ultrasound on bone. Perspectives for dentistry?

Low-intensity ultrasound is frequently used for non-invasive diagnostic purposes. However, low intensity ultrasound can also be used as a therapeutical agent. It has been concluded from animal experiments that it significantly stimulates the growth of bone. In clinical trials an accelerated healing of fracture has been found. Future research has to define the role in dentistry and the final therapeutical value of low intensity ultrasound.     

Unusual vascular hamartoma of the hard palate. A case report

Hamartomas are tumour-like malformations usually present since birth or which may develop during puberty. Hamartomas are related to anatomical development errors. Hamartomas are rarely found in the head and neck district. The case of an unusual vascular hamartoma localised in the hard palate of a 50-year-old female with no significant medical or family history is reported. Surgical treatment was performed by means of an excisional biopsy.     

Die FAMI-Schraube für die temporäre intermaxillare Fixation

The aim of this study was to demonstrate the suitability of the FAMI screw (fixation and adaptation in mandibular injuries) for maxillomandibular fixation in the maxillofacial area in orthognathic and trauma surgery. This FAMI screw was used in 28 patients for maxillomandibular fixation with wiring or elastics. The screw is inserted into the labial or buccal surfaces of the alveolar process without predrilling. Adequate intermaxillary fixation with balanced occlusion was created intraoperatively in all patients. In comparison with conventional splinting methods, this technique was far less time-consuming. The use of the FAMI screw has the advantage of being quick and simple, particularly if only a brief period of maxillomandibular immobilization is planned. Furthermore, the risk to the surgeon of sustaining a puncture injury from wire ligatures is distinctly reduced. Screws can be removed without local anesthesia. The above-mentioned method is minimally traumatic, effective, timesaving, and hence inexpensive. It can be used for maxillomandibular immobilization in dentate as well as in edentulous patients.     

Preemptive rofecoxib and dexamethasone for prevention of pain and trismus following third molar surgery *

Objective The goal of this preliminary randomized prospective clinical trial was to compare the analgesic efficacy and the reduction in trismus of preoperative rofecoxib, intraoperative dexamethasone, and both rofecoxib and dexamethasone following third molar extraction surgery. Study design Thirty-five subjects requiring surgical removal of at least 1 partial bony impacted mandibular third molar were invited to participate in this double-blind and double-dummy placebo-controlled clinical trial. Subjects were randomly assigned into 1 of 4 treatment groups: (1) placebo po preoperatively and placebo IV intraoperatively; (2) rofecoxib 50 mg po preoperatively and placebo IV intraoperatively; (3) placebo po preoperatively and dexamethasone10 mg IV intraoperatively; and (4) rofecoxib 50 mg po preoperatively and dexamethasone 10 mg IV intraoperatively. Subjects completed a diary assessing postoperative pain onset and intensity using categorical and visual analogue scales. Interincisal opening was assessed 1, 2, 3, and 7 days postoperatively using a Therabite ruler. Results This randomized controlled clinical trial enrolled 35 subjects. Two subjects did not meet the inclusion criteria and 4 did not return completed diaries. The mean age of the remaining 29 subjects (11 males, 18 females) was 22.8 years (+/- 0.6 year). The active treatments tended to delay the need for initial pain medication. When compared to other active treatments and to placebo, the combination of preoperative rofecoxib and intraoperative dexamethasone significantly reduced initial pain intensity ( P < .05). Baseline interincisal opening was 52.6 mm (+/- 6.2). The greatest decrease in interincisal opening was 43.3% for the placebo group at 24 hours. Preoperative rofecoxib alone showed a decrease in interincisal opening of 42.3% ( P = ns) at 24 hours. Intraoperative dexamethasone alone showed a decrease in the interincisal opening of 24.1% of baseline ( P < .05 vs placebo). The group receiving the combination of rofecoxib and dexamethasone showed a decrease in interincisal opening of 23.7% of baseline ( P < .05 vs placebo). Conclusions The results of this trial indicate that the use of intraoperative dexamethasone is an effective therapeutic strategy for limiting trismus following surgical removal of impacted third molars. The combination of preoperative rofecoxib 50 mg and intraoperative dexamethasone 10 mg was most effective in minimizing pain and trismus following third molar surgery.