Aim: The aim of this study was to investigate the quality of bone at the augmented site in the anterior maxilla and mandible. Materials and methods: Ten patients with inadequate bone for implant placement were included in this study. Of these 10 patients with inadequate bone volume, five were chosen to be treated with autogenous bone grafts (AT) and rest five patients were treated with freeze dried corticocancellous allografts (AL). Three months following grafting, biopsies of the grafted area were obtained using a 3 mm trephine bur and were histologically evaluated. Results: Histological analysis revealed areas of new bone formation with thick trabeculae with lacunae containing osteocytes in the autogenous group, whereas the allograft group showed segments of necrotic bone with empty lacunae. Although, the AL group has an inherent advantage of avoidance of a secondary surgical site, showed decreased bone remodeling as compared to the autografts. Conclusion: All the 10 patients underwent implant placement. The reports regarding the nature of bone obtained during implant placement clearly depicts a comparable histological variation at the grafted site.

Objective: This study aims to measure and compare the accuracy of various implant impression techniques in specimens with parallel implants placed at 90° to the horizontal plane and at 75°. Materials and methods: Polyether medium body (3M ESPE Impregum) was selected as the material of choice. Two metal samples with three lab analogs placed in each were used as the master models. One had implants placed at 90° to the horizontal plane, and the other at 75°. Ten impressions were made each of stock metal tray, closed custom tray and open custom tray techniques. Photographs were taken and measure ments were made using Adobe Photoshop software. Intragroup comparisons were done using the analysis of variance (ANOVA) and one way ttest. Intergroup comparison was done using two way ttest. Results: All the techniques studied showed some distortion and the difference had no statistical significance. However, closed custom tray technique gave better results for the 90° specimen, and open custom tray technique gave better results for the 75° specimen. Conclusion: Within the limitations of this study, it can be concluded that provided operator error is minimized and guide lines are followed, it may be possible to achieve impressions of similar accuracy regardless of technique used. However, it was impossible to achieve a level of exactness that would ensure a completely passive fitting prosthesis.

Background: Periodontal pocket is a dynamic environment. Several interacting factors within this microenvironment play an important role in initiation and progression of periodontal diseases. Power of hydrogen (pH) is one of the important governing factor. Evidence suggests that pH of healthy gingival sulcus is between mildly acidic to neutral. A shift toward alkaline pH is observed in periodontal pocket which favors growth of gram-negative periopathogenic bacteria. Thus, the aim of the current study is to assess possible role of ascorbic acid in rever sing subgingival alkaline pH and to determine optimum con centration of ascorbic acid for bacteriocidal effects. Materials and methods: Subgingival plaque samples from 37 generalized chronic periodontitis patients were collected. Growth inhibition of periodontal pathogens with four different concentrations of ascorbic acid was examined anerobically after 48 hours. Photometric analysis and disk diffusion method were employed to quantify inhibitory effects. Results: Evidence obtained by both the methods demonstrated possible bactericidal activity of ascorbic acid at 5 mg/ml. At this concentration, ascorbic acid showed stronger pH dependent inhibition toward gram-negative periopathogens. Conclusion: Ascorbic acid can inhibit growth of periodontal pathogens at high concentration. Subgingival vitamin C administration could lead to prevention of plaque induced diseases. Due to its acidic nature, it should be used cautiously around teeth but recommended for maintenance of implants.

Objective: To assess and compare the marginal fit of screw retained three unit implant superstructure, before and after spark erosion. Methodology: An experimental model was prepared on which three unit screw retained implant superstructure on two implant analogs (cortex system) was fabricated which was then subjected to spark erosion. Sheffield test (one screw test) was carried out to determine the passivity. Assessment of vertical discrepancy was carried out using stereomicroscopic images of the superstructure and implant analog junction pre- and post-spark erosion with the help of image J analysis software. Results: The implant superstructure fabricated with the conventional casting method were fitting actively on the implant analogs indicating a negative Sheffield test. However, following spark erosion passive fit was achieved. The marginal fit of the cast implant superstructure measured from a reference point on the superstructure to the implant analog margin was 4324.56 μm before spark erosion and 4046.57 μm after spark erosion. Conclusion: Spark erosion technology with further research can be used to maximum efficiency to obtain passive fit of implant superstructure.

Unlike natural teeth, osseointegrated implants react bio mechanically in a different fashion to occlusal load due to lack of the periodontal ligament. Hence, the dental implants may be more prone to occlusal overloading, which is often regarded as one of the potential causes for periimplant bone loss and failure of the implant/implant prosthesis. Stability of the intercuspal position and reduction of lateral forces are important aspects when providing occlusal equilibration for implantsupported prosthesis. Multiple missing teeth in maxillary and mandibular arches with disturbed occlusal plane due to longterm edentulous condition and overeruption of remaining teeth into the edentulous spaces is the challenging clinical situation. This article describes the management of a patient with multiple missing teeth in both the arches with mandibular implantsupported overdenture and maxillary implant supported fixed prosthesis. The sequence of the treatment planning is highlighted to manage the complex situation to achieve the best predictable occlusion.

Yttria-tetragonal zirconia polycrystal (Y-TZP) is a material globally accepted for restorative and implant dentistry. The patient's increased demand for more biologic and esthetic materials has made metal-free treatment a routine in everyday dental practice. Zirconia implants have more recently appeared into our armamentarium and is today the treatment of choice for patients with metal allergies and other immune disorders that are related with metal sensitivities as well as esthetic demanding cases. The present case report describes the protocol used for immediate zirconia implants and immediate loading for the full-mouth rehabilitation using computer-aided design/computeraided manufacturing (cad/cam) technology.