The effect of chlorhexidine gluconate as an endodontic irrigant on the apical seal: long-term results

The purpose of this study was to determine whether chlorhexidine gluconate (0.12%), used as an endodontic irrigating solution, would affect the apical seal of three root canal cements. One hundred, extracted, human, single-canal teeth were divided into 9 experimental groups of 10 teeth each, in addition to a positive and negative control group of 5 teeth each. The teeth were decoronated at the level of the CEJ, accessed, instrumented to a Master apical file #50, irrigated with either sterile saline, 5.25% NaOCl, or 0.12% chlorhexidine gluconate, and dried using paper points. Obturation was accomplished using lateral condensation and one of three endodontic sealers: Roth's 811, AH 26, or Sealapex. Postobturation apical leakage was measured at 270- and 360-day observation periods using the fluid filtration method. Using the mixed-model repeated-measures ANOVA test with Tukey's honest significance difference multiple comparison procedure, the results showed the saline-Sealapex combination had significantly more leakage (p < 0.05) than either the Peridex-Sealapex or saline-Roth's combinations at 270 days. No other significant differences were noted between any sealer-irrigant combination at 270 days. The saline-Sealapex combination had significantly more leakage than the saline-Roth's combination at 360 days. No other significant differences were noted at 360 days. Under the conditions of this study, chlorhexidine gluconate irrigant did not adversely affect the apical seal of three root canal cements at 270 and 360 days.     

The interleukin-1 polymorphism,smoking, and the risk of periodontal disease in the population-based SHIP study

Several studies have shown a role for interleukin-1 gene cluster polymorphisms in the risk assessment for periodontal diseases. In the Study of Health in Pomerania (SHIP), 3148 subjects were randomly selected from the population and assessed for a broad range of diseases and environmental/behavioral risk factors. From the complete study group in the age 40 to 60 years, N = 1085 subjects were genotyped for the interleukin-1 genotype composite polymorphism in relation to periodontal parameters. The study objective was to elucidate the gene-environment interaction between the risk factors smoking and IL-1 polymorphism. An increased risk of periodontal disease was found for IL-1 genotype-positive smokers: odds ratio adjusted for age, sex, education, and plaque OR = 2.50 (95% C.I. 1.21 to 5.13; p = 0.013). This was not the case with subjects who never smoked: OR = 1.09 (0.73-1.62; p = 0.676). These results support the hypothesis of gene-environmental interaction in periodontitis.     

Evidence that experimentally induced sleep bruxism is a consequence of transient arousal

Spontaneous rhythmic masticatory muscle activity (RMMA) during sleep occurs more frequently following spontaneous transient micro-arousal in patients with sleep bruxism (SB) and normal controls. Here, we tested the hypothesis that an experimental arousal would be followed by an increase in RMMA. We identified RMMA on polygraphic recordings taken before and after sensory stimulation to induce experimental arousal in eight SB patients and eight matched normal subjects. The rate of experimental arousal and the level of resting electromyographic activity in masseter and suprahyoid muscles during sleep did not differ between the groups. In both, muscle tone and heart rate increased during the experimental arousal. Although post-arousal RMMA occurred in all SB patients, it was seen in only one normal subject. Moreover, tooth-grinding occurred during 71% of the evoked RMMA in SB patients. These results support the hypothesis that SB is an exaggerated form of oromotor activity associated with sleep micro-arousal.     

3-D Finite element analysis of all-ceramic posterior crowns

The purpose of this study was to evaluate the stress distribution under various loading conditions within posterior all-ceramic crowns. A three-dimensional finite element model representing a lower first molar was constructed. Variations of the model had two types of single layer all-ceramic crowns (Dicor and Empress) and two types of double layer all-ceramic crowns (In-Ceram and Empress2) cemented. A load of 600 N, simulating the maximum bite force, was applied vertically to the crowns. Loads of 225 N, simulating masticatory force, were applied from three directions (vertically, at a 45 degrees angle, and horizontally). In the test simulating maximum bite force, the maximum tensile stresses on all crowns (17.4-19.4 MPa) concentrated around the loading points. In the masticatory force simulation test, the specimens experienced maximum tensile stresses of 19.7-27.0 MPa under a horizontal load and 10.8-10.9 MPa under a vertical load. When the load was applied horizontally, the maximum tensile stress was observed around the loading points on the surface in the case of the single layer crowns, and of the cervical area of the inner core of the double layer crowns. Within the limitation of this study, it was found that the strength of occlusal contact points is important to the integrity of posterior all-ceramic crowns and that bite forces applied from the horizontal direction are a critical factor.     

Smoking as a risk indicator for periodontal disease in the middle-aged Vietnamese population

BACKGROUND: Studies from developed countries have found smoking a significant risk indicator for periodontitis. However, few such studies have been conducted in developing populations, where the natural history of the disease is rarely confounded by treatment and smoking is highly prevalent. AIM: The present study aimed to confirm the consistency, strength and dose-response of the association of smoking with periodontitis measured by loss of attachment (LOA) in a representative middle-aged adult sample from a developing country. METHODS: A cross-sectional study with a multistage stratified random sample was conducted in two provinces of Vietnam. RESULTS: A total of 575 (response: 84.6%) 35-44-year-old subjects were interviewed and periodontally examined. Data were re-weighted to represent the population of the provinces. 28.9% were current smokers (CS), 8.6% former smokers (FS) and 62.5% never-smokers (NS). Number of cigarette pack-years was calculated to divide CS into light smokers, LS < or = 5 pack-years, and heavy smokers, HS 5+ pack-years. The US NIDR protocol was employed for LOA measurement at two sites per tooth for every tooth. HS presented with the highest prevalence of LOA exceeding various thresholds followed by LS (chi2, P < 0.001). The extent of sites with LOA > or = 4 mm and LOA > or = 6 mm was significantly higher among HS and LS compared to NS (ANOVA; P < 0.001). The severity scores of LOA for NS, FS, LS and HS were 2.42, 2.50, 2.64 and 3.05 mm respectively (ANOVA; P < 0.001). Disease cases were defined as having 2+ sites with LOA > or = 5 mm and 1+ site with PD > or = 4 mm. Compared to NS, the odds ratio for periodontitis among heavy smokers was 7.17 (CI: 2.87-17.92, P < 0.001). CONCLUSION: Smoking is a risk indicator for periodontitis among the middle-aged Vietnamese population. To pursue a population prevention approach for periodontitis, dentistry in Vietnam needs to be part of antismoking and smoking cessation programs.     

Oral and intestinal microflora in 5‐fluorouracil treated rats,translocation to cervical and mesenteric lymph nodes and effects of probiotic bacteria

Serious systemic infections may occur during cancer chemotherapy due to disturbances in the oropharyngeal and gastrointestinal microflora, impaired mucosal barrier functions and immunosuppression. Bacteria may spread from the gastrointestinal tract to the regional lymph nodes. The routes for bacterial spread from the oral cavity are less well known. In the present study we investigated changes in the oral and intestinal microfloras in rats given 50 mg/kg 5‐fluorouracil (5‐FU) i.v. for 6 days. Bacterial dissemination to the lymph nodes draining the oral cavity and the lymph nodes draining the gastrointestinal tract was examined. Effects of adding the probiotic strain Lactobacillus plantarum 299v in the drinking water to the rats were measured. 5‐FU treatment caused an increase in the number of facultative and strictly anaerobic bacteria in biopsies from the oral cavity and an increase in the number of facultative anaerobes in the large intestine. The proportion of facultative gram‐negative rods increased in both the oral cavity and intestine. Bacteria translocated to both the cervical and mesenteric lymph nodes in untreated animals and increased in numbers after 5‐FU treatment due to an increase in the number of facultative gram‐negative rods. Treatment with L. plantarum 299v improved food intake and body weight in 5‐FU‐treated rats. It also reduced the 5‐FU‐induced raise in the total numbers of facultative anaerobes in the intestine, but did not reduce translocation and did not prevent diarrhea. This study reinforces the oral cavity, along with the gastrointestinal tract, as a source for bacterial dissemination. The use of probiotic bacteria may reduce some side effects of 5‐FU treatment.     

Comparison of the bleeding on marginal probing index and the Eastman interdental bleeding index as indicators of gingivitis

AIM: The purpose of the present study was to compare 2 indices, i.e., the Eastman interdental bleeding (EIB) index and the bleeding on marginal probing (BOMP) index. The comparison was made (a) in terms of the degree of bleeding provoked and the relationship with plaque in natural gingivitis and (b) for the ability of these 2 methods to detect differences between the development of experimental gingivitis in a control group and a group in which the development of gingival inflammation was suppressed by treatment. For the present studies, subjects were selected without interdental recession of the gingival tissues. METHODS EXPERIMENT 1: In this experiment, 43 subjects having established moderate gingivitis were assessed using a random splitmouth design (1st and 3rd/2nd and 4th quadrant). Plaque was scored on all approximal sites after which the BOMP index was assessed in one half of the mouth and the EIB index in the other. RESULTS EXPERIMENT 1: The BOMP index showed a bleeding score of 84% and the EIB index of 87%. The significant correlation between plaque and gingival bleeding for the BOMP index (0.55) was higher than for the EIB index (0.44). METHODS EXPERIMENT 2: For this experiment, 25 subjects participated in an experimental gingivitis trial of the lower jaw. At baseline, first the BOMP index and immediately thereafter the EIB index were assessed at all approximal sites. Experimental gingivitis (EG) was carried out in one randomly assigned quadrant and as a treatment modality only floss was used in the other (FL). RESULTS EXPERIMENT 2: In the EG quadrant, the BOMP index increased to 69% and the EIB index to 73%. Both indices showed a significant correlation with plaque; 0.60 and 0.64 respectively. In the FL quadrant, the BOMP index increased to 38% and the EIB index to 30%. No significant correlation between both gingivitis indices and the amount of plaque was present in the FL quadrant. CONCLUSION: The ability of the BOMP index and the EIB index to assess the level gingival inflammation appears to be comparable.     

Paracetamol versus paracetamol-codeine in the treatment of post-operative dental pain: a randomized,double-blind,prospective trial

BACKGROUND: Codeine is frequently added to paracetamol to treat post-operative dento-alveolar pain; studies have shown effectiveness in relief of post-operative pain at high doses but at the expense of central nervous and gastrointestinal side effects. There has been no trial to compare the efficacy and safety of paracetamol 1000 mg with paracetamol 1000 mg combined with codeine 30 mg. METHOD: A randomized, single centre, double-blind prospective parallel group trial was performed to compare paracetamol 1000 mg with paracetamol 1000 mg with codeine 30 mg for the relief of pain following surgical removal of impacted third molars, and analysed on an intention-to-treat (ITT) basis. Eighty-two patients were assigned randomly to receive either drug for a maximum of three doses. Patients recorded their pain intensity one hour after surgery and hourly thereafter for 12 hours. RESULTS: The average increase in pain intensity over 12 hours was significantly less in patients receiving paracetamol plus codeine than in those receiving paracetamol alone (p=0.03) -1.81 cm/h compared with 0.45 cm/h - a difference of 1.13 cm/h (95 per cent CI: 0.18 to 2.08). Of the patients who received the paracetamol codeine combination, 62 per cent used escape medication compared with 75 per cent of those on paracetamol alone (p=0.20). There was no significant difference between the two groups in the proportion of patients experiencing adverse events (p=0.5). CONCLUSION: A combination of 1000 mg paracetamol and 30 mg codeine was significantly more effective in controlling pain for 12 hours following third molar removal, with no significant difference of side effects during the 12 hour period studied.