Remineralization efficiency of bioactive glass on artificially induced carious lesion an in-vitro study.

OBJECTIVES: The objective of this study is to investigate the efficacy of bioactive glass containing product on remineralization of artificial induced carious enamel lesion and to compare its efficiency with other remineralization products using an in-vitro pH cycling method. The null hypothesis tested was bioactive glass has no effect on enamel remineralization. MATERIALS AND METHODS: A total of 20 enamel samples of human molar teeth were subjected to artificial caries lesion formation using pH cycling method and was verified using high resolution scanning electron microscope (HRSEM). Each demineralized sample was then divided into five test groups each containing twenty. Group A - Bioactive glass (SHY-NM), Group B - Fluoride tooth paste (Amflor), Group C - CPP-ACP (Tooth mousse), Group D - CPP-ACPF (Tooth mousse plus), Group E - control. All the test groups were exposed to the pH cycling regime, the remineralizing agents were applied for 10 min except control. After 10 days period, the entire test groups were evaluated with HRSEM and quantitative assessment by energy dispersive X-ray spectroscopy. The obtained data was analyzed statistically using one-way ANOVA, Student's t-test and Tukey's multiple comparison tests. P ≤ 0.05 was considered to be significant. RESULTS: Rejection of the null hypothesis and highlights the concept of biomimetic bioactive glass as an effective remineralizing agent. CLINICAL RELEVANCE: To focus on the importance of minimal invasive treatment on incipient carious lesion by remineralization.

Deflections in Mandibular Major Connectors: A FEM Study.

The major connector is the most vital component critically subjected to maximal stress concentration due to various forces acting on it. The main requirement of a major connector is its resistance to deformation by occlusal stresses. This resistance to deformation is a direct consequence of the rigidity of the major connector. Thus rigidity of the major connector is paramount to resist flexing and torquing forces that could be transmitted to the abutment teeth and other structures as destructive forces. The commonly used major connectors for the mandibular arch are lingual bar and lingual plate. In the present study, the deflection of various major connector designs due to occlusal load is assessed by finite element method. They have been analyzed through finite element models. The differences in the deflection behaviour of mandibular major connector used in Kennedy's Class I, Class II, Class III, and Class IV edentulous situations have been compared. A CT scan of human edentulous mandible was taken and each section from symphysis to condylar region was projected on a graph paper and three-dimensional volumes were created from connected successive profiles to define the final solid geometry of cortical bone. Six framework models with different mandibular major connectors, lingual bar and lingual plate for Kennedy's Class I, Class II, Class III, and Class IV situations were created. The three dimensional finite element models corresponding to the geometric model were generated using Ansys's pre-processor. The model was assigned material properties. A vertical biting force of 20 N was applied. The results showed that the maximum deflection was seen in the saddle area when compared to other areas, i.e., major connector and the occlusal rest regions. The lingual bar in Kennedy's Class III situation and lingual plate in Kennedy's Class IV situation showed the least deflection when compared to Class I and Class II (distal extensions) situations. Lingual plate is more rigid major connector than lingual bar.

Force transfer and stress distribution in an implant-supported overdenture retained with a hader bar attachment: a finite element analysis.

Background and Objectives. A key factor for the long-term function of a dental implant is the manner in which stresses are transferred to the surrounding bone. The effect of adding a stiffener to the tissue side of the Hader bar helps to reduce the transmission of the stresses to the alveolar bone. But the ideal thickness of the stiffener to be attached to the bar is a subject of much debate. This study aims to analyze the force transfer and stress distribution of an implant-supported overdenture with a Hader bar attachment. The stiffener of the bar attachments was varied and the stress distribution to the bone around the implant was studied. Methods. A CT scan of edentulous mandible was used and three models with 1, 2, and 3 mm thick stiffeners were created and subjected to loads of emulating the masticatory forces. These different models were analyzed by the Finite Element Software (Ansys, Version 8.0) using von Mises stress analysis. Results. The results showed that the maximum stress concentration was seen in the neck of the implant for models A and B. In model C the maximum stress concentration was in the bar attachment making it the model with the best stress distribution, as far as implant failures are concerned. Conclusion. The implant with Hader bar attachment with a 3 mm stiffener is the best in terms of stress distribution, where the stress is concentrated at the bar and stiffener regions.

Bilateral implant-retained auricular prosthesis for a patient with congenitally missing ears. A clinical report.

Microtia is a major congenital anomaly of the external ear. It includes a spectrum of deformities from a grossly normal but small ear to the absence of the entire external ear. These deformities account for three in every 10,000 births, with bilaterally missing ears seen in fewer than 10% of all cases. Congenital abnormalities of the ear are unlikely to result in the complete absence of the ears, but the patient presented in this article had bilateral congenitally missing ears. There was loss of anatomic landmarks and alteration of normal bony architecture. Minimal tissue was available for retention; therefore, conventional techniques could not be used for achieving retention. A two-implant-supported auricular prosthesis was planned, but the patient was found to have deficient bone in the implant site. Hence the implants were placed posterior to these sites, and the superstructure was modified to accommodate for this change in position of the implant to ensure the esthetic positioning of the prosthesis.

A finite element analysis of stress distribution in the bone, around the implant supporting a mandibular overdenture with ball/o ring and magnetic attachment.

Today implant dentistry has made great inroads into the treatment modalities that are available in treating an edentulous patient. Popularity of a two implant retained overdenture has created a necessity to examine the various attachment systems being used and the stresses that are transmitted to the alveolar bone. Hence a Three dimensional Finite Element Analysis was done to analyze the stress distribution in the mandibular bone with implant-supported overdenture having Ball/O-ring and Magnet attachments of different diameters. A segment of the anterior region of the mandible was modeled with implant and the overdenture. Four different models were generated having Ball/O-Ring and Magnet Attachments. Forces of 10 N, 35 N and 70 N were applied from the horizontal, vertical and oblique directions respectively and the stress distribution studied. It was concluded that the greatest stress concentrations were seen at the crest of the cortical bone and could be reduced by using smaller sized attachments for implant supported-overdenture.