A study of the bond strength and color of ultralow-fusing porcelain

PURPOSE: The purpose of this study was to investigate the effects of different bonding agents, surface roughness, and acid pickling on the bond strength and color of ultralow-fusing porcelain fused to gold alloy. MATERIALS AND METHODS: Porcelain-metal specimens were made to 25 mm x 3 mm x 0.5 mm with a 1-mm porcelain thickness. A 3-point bending test was used to evaluate the bond strength. The color of the porcelain was measured using a dental chromameter, and the data were processed in the CIE Lab system. The color difference (delta E*) was calculated for the tested groups. RESULTS: Good bond strength and color could be achieved regardless of the use and type of bonding agent. Surface roughness and acid pickling had more effect on the bond strength than on color. CONCLUSION: The type of the bonding agent, surface roughness, and acid pickling influenced the bond strength but had minimal effects on the color of ultralow-fusing porcelain. This ultralow-fusing porcelain could produce a color closer to the Vita shade than the conventional low-fusing porcelain.     

Simplified adhesion of compomers in pediatric dentistry.

A self-etching adhesive agent for bonding polyacid-modified resin-based composite materials ("compomers") to enamel and dentin is now available. The Prompt L-Pop system simplifies and hastens dental bonding procedures and has proved itself useful in many adhesive dentistry applications. This article describes the bonding system and shows clinical examples of its use in children and teenagers. The concept will have further application in adhesive dentistry with introduction of a new formulation of Prompt, to be used with traditional resin-based composite materials.     

Conservative approach in the management of mandibular fractures in the early dentition phase. A case report and review of the literature

A case is described of the management of bilateral fractures of mandible as a result of being kicked by a horse, in a 2-year-old child. The fractures were treated without any surgical intervention and the child made a good recovery with good function and appearance. The fractured mandible in children under the age of 5 years provides us with difficult treatment options. By encompassing the anatomical and developmental potential of facial tissues, both hard and soft, the majority of these cases can be managed conservatively. This negates the disadvantages of attempting potentially growth disturbing interventional surgery.     

Efficacy of a computerized local anesthesia device in pediatric dentistry

PURPOSE: The purpose of this study was to evaluate the efficacy of a computerized anesthesia delivery system in reducing pain during injections when compared with a traditional delivery system (i.e., syringe). METHODS: Subjects consisted of 57 patients between the ages of 5 and 13 needing operative dentistry using local anesthesia. Patients were randomly assigned to either the computerized or traditional anesthesia delivery system. Inferior alveolar block injections, palatal, and buccal infiltrations were the only injections administered throughout this study. Pain behavior was videotaped and coded throughout the study. Pain perceptions were rated using a 10 point visual analogue rating scale. Subjects were also asked to rate their overall satisfaction and approval of the dentist and the treatment received. RESULTS: Results of multivariate analysis of variance indicated that there were no significant differences between the computerized and the traditional method of administering local anesthesia when comparing pain ratings and pain behavior. Average pain ratings for the computerized method were 4.5 while the average ratings for the traditional method were 3.6. In addition, all subjects reported overall satisfaction with their dental treatment and that they would be willing to return in the future. CONCLUSIONS: A computerized anesthesia injection method was found to be comparable to the traditional method of anesthesia injection.     

Oral microbiota in smokers and non-smokers in natural and experimentally-induced gingivitis

Abstract. The present study primarily aimed at investigating the oral microbiota in smokers and non-smokers with established gingivitis and monitoring its composition during experimental gingivitis. Secondly, it aimed at examining whether the composition of the microbiota is associated with different levels of gingival inflammation during this experimental gingivitis trial. For this purpose, 25 non-dental university students with gingivitis were recruited. 11 subjects were smokers and 14 were non-smokers. After achieving gingival health, they entered a 14-day experimental gingivitis trial. Plaque and bleeding were assessed before entering into the study (intake), at day 0. day 5 and at day 14 of the experiment. Microbiological samples from mucosal sites and dental plaque (taken at intake, day 0, and day 14) were analysed for the presence of Actinomyces species. Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Fusobacterium nucleatum, Peptostreptococcus micros. Porphyromonas gingivalis, Prevotella intermedia and Streptococcus species. At day 14 of the experimental period, the level of plaque formation was not different between smokers and nonsmokers, but bleeding scores were lower in smokers than in non-smokers (15% and 30%) respectively, p= 0.01). The change from natural gingivitis to a state of gingival health and a subsequent change from gingival health to experimentally induced gingivitis was accompanied by quantitative alterations in the cultivable microbiota in both groups. Changes were most prominent in the transition from gingival health to experimental gingivitis and were found in dental plaque for Actinomyces species, C. rectus, F. nucleatum, and P. intermedia. Within the group of non-smokers, a distinction was made between subjects with a‘weak’or 'strong’inflammatory response. No relationship with a single bacterial species could be established which would likely explain the differences in levels of inflammation. It is concluded that differences in response to experimental gingivitis are not caused by major differences in the composition of the oral microbiota.     

Comparative unsupervised clinical trial on caries inhibition effect of monofluorophosphate and amine fluoride dentifrices after 3 years in Strasbourg, France

A randomized, double blind clinical trial of the caries inhibition effects of dentifrices containing respectively monofluorophosphate and amine fluoride was performed. A third control group used a toothpaste without fluoride. A total number of 2008 schoolchildren ranging in age from 6 to 8 years and living in Strasbourg (France) participated in this study. After a baseline examination three groups were constructed with the block randomization technic. The caries inhibition effects of the three dental pastes were compared after 3 years of unsupervised use. The monofluorophosphate dentifrice showed a reduction of 7.02% for DMFT, 5.17% for DMFS and 25.26% for the df rate. The reduction of amine fluoride dentifrice caries was respectively 21.62% for DMFT, 20.94% for DMFS and 48.66% for the df rate.     

Ultrastructure of odontoblasts in kitten tooth germs as revealed by freeze-fracture

Fifteen kittens were perfused with 2.5 per cent glutaraldehyde or modified Karnovsky fixative. Distribution and structural features of the three kinds of intercellular junctions: gap junctions, macular tight junctions and desmosome-like junctions were clarified by correlated observations using thin sections and freeze-fracture replicas. Distal junctional complexes of the odontoblasts were composed of both gap and macular tight junctions and sealed extracellular spaces incompletely, because of the poor sealing capacities of macular tight junctions. Therefore, there was no predentine-pulp barrier in the odontoblast layer. Except for the junctional complex, no tight junction was observed in the odontoblasts. Gap junctions and desmosome-like junctions were found between adjacent odontoblasts and between odontoblasts and neighbouring pulp cells. Gap junctions were similar to those of many other tissues but the desmosome-like junctions were different from mature desmosomes in the epithelial cells and showed immature features. Each intercellular junction of odontoblasts is considered to form a site of intercellular communication and cell-to-cell attachment.