Randomized Controlled Study on Effect of Concentrated Growth Factors on Crestal Bone Levels and Peri-implant Bone Density in Dental Implants.

Introduction: Modern dentistry aims to restore the comfort and health of the stomatognathic system. Dental implants have emerged as a promising option for this purpose. Concentrated growth factors (CGFs) have been suggested to enhance the healing of bone grafts and enhance the integration of implants into the bone. Growth factors are proteins which regulate the complex process of wound healing. They play an important role in cell migration, cell proliferation, and angiogenesis in the tissue regeneration phase. CGF was first developed by Sacco in 2006. It can be used as a barrier membrane to accelerate soft-tissue healing. CGF does not require any chemical or anticoagulants, and hence, it is free from viral transmission diseases. Crestal bone levels, peri-implant bone density, bleeding, probing depth, mobility, occlusion factors, restoration adequacy, radiographic images, oral hygiene, and patient health status are some of the important parameters for determining longevity of success rates in implant dentistry. This study will assess the peri-implant bone density and crestal bone levels with and without the use of CGF. Aim: To evaluate the effect of CGFs on peri-implant bone density and in the preservation of crestal bone levels around dental implants. Materials and Methods: Sampling procedure: Random selection of population (Sealed envelope method)Number of groups: Two-Control group (Group 1) and Experimental group (Group 2)Sample size: 20 For Group 2, implants were placed with CGF. For Group 1, implants were placed without CGF. The peri-implant bone density and bone levels were measured by Digora and signora software. Results: The mean crestal bone loss on the mesial aspect of implants placed in Group 2 is 0.294 mm and Group 1 is 0.345 mm, and the mean crestal bone loss on the distal aspect of implants placed in Group 2 is 0.320 mm and in Group 1 is 0.331 mm. There are no many significant differences on mesial and distal aspects around implants between the two groups Intragroup comparison of bone density values in Group 1 shows the mean difference from baseline to 1 month is 0.6, and after three and 6 months periods are 1.1 and 1.1, respectively, which indicates not much significant improvement in bone density values in Group 1. Intergroup comparison shows a significant difference between both the groups starting from as early as the 1st month. Conclusion: The results of this study indicate that CGF is significantly better in the regeneration of bone around the implants when comparing with nonCGF groups. Although CGF showed improvement in bone formation, there are no many differences in crestal bone level changes on mesial and distal sides of the implants between the two groups.

Mylohyoid Ridge as a Predictor of Available Bone for Implant Placement: A Cone-Beam Computed Tomography (CBCT) Retrospective Observational Study.

INTRODUCTION: The posterior mandibular region, due to the presence of vital structures, poses a high risk during implant placement because of its susceptibility to neurovascular injury and perforation of the lingual cortex. A breach in implant length and available bone height may lead to serious intraoperative and postoperative complications. Prediction of the exact location of the inferior alveolar nerve and submandibular fossa anatomy is a prerequisite for ideal implant placement, which is always not possible with conventional radiographic and clinical techniques. MATERIALS AND METHODS: One hundred ten cone-beam computed tomographies (CBCTs) of patients were acquired from the radiological archives of a radiological center in Chennai. DICOM files from CBCT were exported to Bly Sky Plan software. Cross-sections of the second molar and first molar were extracted following the inclusion criteria. The linear dimension between the mandibular canal and mylohyoid ridge and anatomic variables of the submandibular fossa were measured digitally on the left and right sides using software measuring tools. Descriptive statistics were done. The unilateral and bilateral site and gender differences were evaluated. Bone height superior to the mandibular canal was correlated with the submandibular fossa parameters; depth of undercut in the vertical and horizontal directions; and angle of the undercut. RESULTS: The mandibular canal was on average 5.5 mm and 4 mm inferior to the Mylohyoid ridge in the second molar region and first molar region, respectively, with the right and left sides showing no statistically significant difference. The depth of fossa undercut in vertical and horizontal dimensions was higher in the second molar region compared to the first molar region. The height of the deepest point of the undercut in the vertical dimensions showed a positive correlation with the bone available between the mandibular canal and the mylohyoid ridge. CONCLUSION: Keeping 2 mm of safety factor in consideration, implants can be safely placed up to the mylohyoid ridge in 100% of cases and 2 mm below the mylohyoid ridge in 78.9% of cases in the mandibular second molar region. In keeping with a safety factor of 2 mm, implants can be safely placed up to the mylohyoid ridge in 82.6% of cases and 2 mm below the mylohyoid ridge in 43.1% of cases in the first molar region. A more pronounced undercut was seen in the second molar region than in the first molar region. Deeper fossa undercuts in vertical dimension are associated with more inferior positioning of the mandibular canal.

In Vitro Comparison of Loss of Torque between Gold and Titanium Alloy Abutment Screws in Dental Implants without Any Cyclic Loads.

AIM: To find and compare the amount of screw loosening in gold and titanium alloy abutment screws without any cyclic load, this study was performed. MATERIALS AND METHODS: A total of 20 implant fixture screw samples with 10 gold abutment screws from Osstem and 10 titanium alloy abutment screws from Genesis. Implant fixtures were placed into the acrylic resin using a surveyor to maintain the same path of insertion. Using a hex driver and calibrated torque wrench, initial torque was given according to the manufacturer's recommendation. One vertical and other horizontal lines were drawn over the head of the hex driver and resin block. Acrylic block position was standardized using a putty index in a fixed table and using a tripod stand a digital single-lens reflex camera (DSLR) camera was positioned with its horizontal arm facing the floor, as well as perpendicular to the acrylic box. Photographs were taken immediately after the application of the initial torque given as per the manufacturer's recommendation and 10 minutes after the initial torque. Re-torque of 30 and 35 N cm was given to gold and titanium alloy abutment screws respectively. Photographs were taken again in that same position immediately after re-torquing and 3 hours after re-torquing. The photographs were uploaded into the Fiji-win64 analysis software and the angulations were measured in each photograph. RESULTS: Both the gold and titanium alloy abutment screws exhibited screw loosening after initial torquing. There was a significant difference in the amount of screw loosening between gold and titanium alloy abutment screws after initial torquing and no change in the abutment screw position after three hours of re-torquing. CONCLUSION: Re-torquing of both gold and titanium alloy abutment screws after 10 minutes of initial torquing should be performed routinely for retaining the preload and minimizing the screw loosening even before loading the implant fixture. CLINICAL SIGNIFICANCE: Gold abutment screws may have the ability to retain the preload better than the titanium alloy abutment screws after initial torquing, re-torquing may be necessary after 10 minutes to reduce the settling effect in a routine clinical procedure.

Asymbiotic seed germination and in vitro conservation of Coelogyne nervosa A. Rich. an endemic orchid to Western Ghats.

Coelogyne nervosa is an epiphytic orchid endemic to Western Ghats, South India. The mature seeds of C. nervosa were cultured on ½ MS (Murashige and Skoog), MS, Kn (Knudson) and VW (Vacin and Went) media to evaluate the seed germination response. Of the four basal media used, MS medium supported maximum seed germination. Further experiments to enhance seed germination were done on MS medium supplemented with various concentrations (10, 20, 30 and 40 %) of coconut water (CW). Thirty percent CW gave the highest response in terms of percent seed germination (96), fresh weight (7.2 mg/seedling) and protocorm length (15.2 mm). Since CW containing medium did not support further seedling growth, each seedling was isolated and cultured on MS medium supplemented with either BA (6-benzylaminopurine) or Kin (kinetin) alone (1.0-4.0 mg/l each) or in combination with NAA (1-naphthaleneacetic acid; 0.2-1.0 mg/l). Maximum growth was observed on MS medium supplemented with BA (3.0 mg/l) and NAA (0.5 mg/l). On this medium, the seedlings reached an average length of 3.6 cm with 2.8 well expanded green leaves per seedling. Similarly optimum, healthy, white root induction (3.3 roots/seedlings) was also observed on the same medium. The rooted seedlings were successfully transplanted to pots with 91 % success. The 2-year-old tissue culture derived plants produced normal flowers and fruits.