Scanning electron microscopy study of new bone formation following small and large defects preserved with xenografts supplemented with pamidronate-A pilot study in Fox-Hound dogs at 4 and 8 weeks.

The aim of the present study was to evaluate the feasibility of SEM and EDX microanalysis on evaluating the effect of porcine xenografts (MP3®) supplemented with pamidronate during socket healing. Mandibular second premolars (P2) and first molars (M1) were extracted from six Beagle dogs. P2 were categorized as small defects (SD) and M1 as large defects (LD). Four random groups were created: SC (small control defects with MP3®), ST (small test defects MP3®+pamidronate), LC (large control defects with MP3®), and LT (large test defects MP3®+pamidronate). At four and eight weeks of healing the samples were evaluated fisically through scanning electron microscopy (SEM), and chemical element mapping was carried out by Energy dispersive X-ray spectroscopy (EDX). After four weeks of healing, SEM and EDX analysis revealed more mineralized bone in ST and LT groups compared with control groups (p<0.05). After eight weeks, Ca/P ratios were slightly higher for small defects (groups SC and ST); in SEM description, in both control and test groups, trabecular bone density was similar to the adjacent mineralized cortical bone. Within the limitations of this experimental study, SEM description and EDX elemental microanalysis have demonstrated to be useful techniques to assess bone remodelling of small and large defects. Both techniques show increased bone formation in test groups (MP3® modified with pamidronate) after four and eight weeks of healing.

Histological and Histomorphometric Evaluation of Zirconia Dental Implants Modified by Femtosecond Laser versus Titanium Implants: An Experimental Study in Fox Hound Dogs.

PURPOSE: This study applied femtosecond laser technology to zirconia dental implants (Bredent GmbH & Co.KG, Senden, Germany) to generate a surface texture of microgrooves over the entire intraosseous surface, analyzing its behavior in an in vivo model in comparison with titanium implants with sandblasted and acid-etched surfaces. MATERIALS AND METHODS: The study used six American Fox Hound dogs. Each received four implants per hemi-mandible, making a total of eight implants per animal. The 48 immediate loaded implants were divided into two groups of 24 titanium implants (control group) and 24 zirconia implants (study/test group), distributed randomly. Bone-to-implant contact (BIC) values and crestal resorption were determined at 1 and 3 months, also measuring calcium, phosphorous, and carbon concentrations by means of energy dispersive x-ray. RESULTS: BIC percentages after 30 days were 51.36% for titanium implants and 44.68% for zirconia implants. After 90 days, values increased to 61.73% in titanium and 47.94% in zirconia implants. After 30 days, there was more crestal bone lost in the titanium group (0.77 mm) compared with the zirconia group (0.01 mm). After 90 days, zirconia implants showed greater marginal bone resorption (1.25 mm) compared with the titanium group (0.37 mm). CONCLUSIONS: The present study shows that zirconia implants with modified surfaces can produce good osseointegration values when compared with titanium implants in terms of BIC and crestal bone resorption at 1 and 3 months.

Histologic and histomorphometric behavior of microgrooved zirconia dental implants with immediate loading.

PURPOSE: The study aims to assess the total soft tissue (ST) width, crestal bone level (CBL), bone-to-implant contact (BIC), and bone density (BD) for zirconia implants textured with microgrooved surfaces and immediately loaded. MATERIALS AND METHODS: This study included 51 implants; one implant from each study group was retained for surface characterization. The 48 remaining implants were inserted randomly in premolar areas of both sides of the healed edentulous lower jaws of foxhound dogs. They were divided into three groups of 16: control (titanium); test A (zirconia), and test B (microgrooved zirconia). The implants were splinted and covered with an acrylic bridge. A split-mouth design was used and immediate occlusal loading was applied on one side, while the other side did not have occlusal contact. ST, CBL, BIC, and BD were evaluated after 3 months. The effects of immediate loading on these parameters were analyzed. RESULTS: All the implants were osseointegrated. ST was established at 3 months with mean values of 2.9 ± 0.4 mm for all groups. No differences were appreciated between loaded and unloaded sides regarding ST (p > .05). CBL showed a mean of 1.2 ± 0.3 mm for all groups without differences between loaded and unloaded sides (p > .05). BIC percentages were significantly higher for loaded all-microgrooved implants (p < .05). BD percentages were higher in areas close to all-microgrooved implants (p < .05) and significantly higher for loaded implants than unloaded. CONCLUSIONS: Within the limitations of the present study, it may be concluded that for zirconia dental implants with microgrooved surfaces and immediate loading, the thickness of STs remains stable resulting in 3 mm mean biologic width, that crestal bone preservation is related to insertion depth, and that higher BIC percentages and increased BD around implants microgrooved over the entire intraosseous area may be expected at 3 months following implant insertion and immediate loading.