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Browsing by Author "John, Vanchit (Vanchit Kurien), 1965-"
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Item Effect of HA-coating and HF etching on experemental zirconia implant evaluation using in vivo rabbit model(2010) Huang, Sung-En; Chu, Tien-Min Gabriel; John, Vanchit (Vanchit Kurien), 1965-; Kowolik, Michael J.; Zunt, Susan L., 1951-; Blanchard, Steven B.The objective of this study was to evaluate the in vivo performance of the hydroxyapatite (HA) coating and hydrofluoric acid (HF) etching zirconia (ZrO) implants and to compare the result with titanium (Ti) implants treated in a similar manner. A total of four different implant types were tested in this study. Threaded zirconia implants with HA coating (Test 1) and zirconia implants with HF-treated surfaces (Test 2) were used to compare to the same size of titanium implants treated in identical fashion (control 1 and control 2). All implants measured about 3.5 mm at the thread diameter and 7.0 mm in total length. Each rabbit received two zirconia and two titanium implants treated in the same manner (either HA-coated or HF-etched). The samples were implanted into the rabbit tibias and retrieved at 6 weeks. Upon retrieval, 24 specimens (6 samples for each group) were fixed and dehydrated. The samples were then embedded undecalcified in PMMA for histomorphometry to quantify the bone-to-implant contact (BIC). Another 24 samples were kept in 0.9% saline and were evaluated using removal torque (RT) analysis to assess the strength of the implant-to-bone interface. The histomorphometric examination demonstrated direct bone-to-implant contact for all four groups. HA particle separation from the implants surface was seen in a majority of the HA-coated samples. No signs of inflammation or foreign body reaction were found during examination. Due to the HA particle smear contamination in the ZrO-HA group, no data was collected in this group. The mean BIC at the first three threads of the Ti-HA, Ti-HF and ZrO-HF were 57.78±18.22%, 46.41±14.55% and 47.41±14.05%, respectively. No statistically significant difference was found pair-wise among these three groups. When comparing the BIC data with the machined-surface implants, a statistically significant difference was found between the Ti-HA versus Ti implant group and the Ti-HF versus Ti implant group. The mean bone area (BA) at the first three threads for Ti-HA, Ti-HF and ZrO-HF showed statistically significant difference (p<0.05) between the ZrO-HF and Ti-HA groups, favoring the ZrO-HF group. The value of the peak removal force could only be collected from the Ti-HA group during the removal torque test. The mean RT value for the Ti-HA group was 24.39±2.58 Ncm. When comparing the RT result with our pilot study using machined-surface implants, the Ti-HA group showed statistically significant (p<0.05) higher values than the machined-surface Ti implants. The result of this study proves the in vivo biocompatibility of all four implant types tested. In the three measurable implant groups, the histomorphologic analysis showed comparable osseointegration properties in this animal model.Item Ridge Dimensional Changes: A Comparative Study of Socket Compression After Dental Extraction with No Compression(2013) Bennett, Duane Everett, II, 1984-; Prakasam, Sivaraman; Blanchard, Steven B.; Parks, Edwin T. (Edwin Thomas), 1955-; Ghoneima, Ahmed; John, Vanchit (Vanchit Kurien), 1965-Exodontia, or extraction of teeth, has been a well-documented dental treatment that forms one of the foundations of dentistry. The steps associated with extracting teeth have changed little in the last century and these steps are largely part of the dogma of dentistry. One such step is that of socket compression post-extraction. Rationale for socket compression after extraction is manifold. They include: shorter healing times, fewer dry sockets and re-approximating walls that were stretched in the elevation and delivery stages of extractions. The purpose of this study was to determine if post-extraction ridge compression negatively affected alveolar ridge dimensions when compared to sites that are not compressed post-extraction. Secondary outcome measures will identify if socket compression/re-approximation affects the rate of soft tissue closure or occurrence of alveolar osteitis. In this study, 14 subjects were recruited. Eight subjects formed the compression group, while six formed the non-compression group. The subjects in the compression group received compression of their alveolar ridges after extraction to approximate their original pre-extraction width. The subjects in the non-compression group did not receive ridge compression. Each subject had pre-extraction and post-extraction CBCT scans along with post-operative follow up visits at 1, 2, and 4 weeks post-extraction. The present investigation found that with respect to changes in ridge width, sites that were compressed did not lose significantly more dimension than those that were not. With respect to ridge height, sites that were compressed did not lose significantly more dimension than those that were not. Sites that were compressed and sites that were not, healed at approximately the same rate, with respect to soft tissue closure. While the results showed a lack of statistical significance between both groups, there appears to be a trend towards the ridge compression group having a smaller ridge width. Such a trend was not noted with soft tissue closure, thereby invalidating the rationale for socket compression after extraction. One of the limitations of this pilot study is the small sample size. Further validation of these results must be done with a larger sample size in order to provide clinical guidance to dental practitioners.