ABSTRACT
Recent literatures show that accelerated Portland cement [APC] and calcium hydroxide Ca [OH]2 may have the potential to promote the bone regeneration. However, certain clinical studies reveal consistency of Ca [OH]2, as one of the practical drawbacks of the material when used alone. To overcome such inconvenience, the combination of the Ca [OH]2 with a bone replacement material could offer a convenient solution.To evaluate the soft tissue healing and bone regeneration in the periodontal intrabony osseous defects using accelerated Portland cement [APC] in combination with calcium hydroxide Ca [OH]2, as a filling material.Five healthy adult mongrel dogs aged 2-3 years old [approximately 20 kg in weight] with intact dentition and healthy periodontium were selected for this study. Two one-wall defects in both mesial and distal aspects of the 3rd premolars of both sides of the mandible were created. Therefore, four defects were prepared in each dog. Three defects in each dog were randomly filled with one of the following materials: APC alone, APC mixed with Ca [OH]2, and Ca [OH]2 alone. The fourth defect was left empty [control]. Upon clinical examination of the sutured sites, the amount of dehiscence from the adjacent tooth was measured after two and eight weeks, using a periodontal probe mesiodistally. For histometric analysis, the degree of new bone formation was estimated at the end of the eighth postoperative week, by a differential point-counting method. The percentage of the defect volume occupied by new osteoid or trabecular bone was recorded Measurement of wound dehiscence during the second week revealed that all five APCs had an exposure of 1-2 mm and at the end of the study all samples showed 3-4 mm exposure across the surface of the graft material, whereas the Ca [OH]2, control, and APC + Ca [OH]2 groups did not show any exposure at the end of the eighth week of the study. The most amount of bone formation was observed in APC group which was significantly different with all other groups [p < 0.05].Despite acceptable soft tissue response of Ca [OH]2, this additive material could not be suggested because of negative effects on bone formation results
ABSTRACT
Thermal injury during dental implant placement and restoration is a clinical concern as it may cause bone damage and compromise osseointegration. The threshold level for heat-induced cortical bone necrosis is 47 degree C for 60 seconds. To measure the amount of heat transferred to the implant-bone interface when a two-piece or one-piece abutment was prepared in vertical and horizontal direction using various time intervals. Three groups of samples [n = 24], one-piece and two-piece implant and natural teeth, were used in this study to compare the amount of heat transferred to the implant-bone interface. This study used cooling system in the 10, 20, 30, and 60 seconds time intervals. The Thermocouples [K type] were attached to each sample at the crestal, middle and apical points. To have a similar condition with the oral cavity, each implant was embedded separately in transparent acrylic resin in a 37 degree C water bath. To have a constant cutting pressure, the turbine was fixed on the stable stand and a 100 g counterweight hanged to it. Then, the bath was fixed in front of it and cutting started at vertical and horizontal directions for 10, 20, 30, 60 seconds. The maximum decrease from 37 degree C was observed in two-piece implant at the apical point [3.95 degree C] after 60 seconds and the minimum decrease was seen in one-piece implant at the crestal point [0.6 degree C] after 60 seconds. Also the minimum increase was observed in the natural teeth at the apical point [0.15 degree C] at 10 seconds and the maximum temperature increase was seen in one-piece implant at the apical point [1.95 degree C] at 20 seconds. Within the limitation of this study, it was concluded that to reduce the thermal damage on the bone tissue, an intermittent cut up to 20 seconds is acceptable. Cutting one-piece implant caused more heat transfer than that of two-piece implant
ABSTRACT
There are limited histomorphometric studies on biologic efficacy of high density tetrafluoroethylen [d-PTFE] membrane. To investigate the healing of surgically induced grade II furcation defects in dogs following the use of dense polytetrafluoroethylene as the barrier membrane and to compare the results with the contra lateral control teeth without the application of any membrane.Mandibular and maxillary 3rd premolar teeth of 18 young adult male mongrel dogs were used for the experiment. The furcation defects were created during the surgery. 5 weeks later, regenerative surgery was performed. The third premolar teeth were assigned randomly to control and test groups. In the test group, after a full thickness flap reflection, the d-PTFE membrane was placed over furcation defects. In the control group, no membrane was placed over the defect. 37 tissue blocks containing the teeth and surrounding hard and soft tissues were obtained three months post-regenerative surgery. The specimens were demineralized, serially sectioned, mounted and stained with Hematoxylin and Eosin staining technique. From each tissue block, 35-45 sections of 10 µm thickness within 60µm interval captured the entire surgically created defect. The histological images were transferred to computer and then the linear measurement ranges of the defects area, interadicular alveolar bone, epithelial attachment and coronal extension of the new cementum were done. Then, the volume and area of afore-mentioned parameters were calculated considering the thickness and interval of the sections. To compare the parameters between the control and test teeth, we calculated the amount of each one proportionally to the original amount of defects.The mean interradicular root surface areas of original defects covered with new cementum was 74.46% and 29.59% for the membrane and control defects, respectively [p < 0.0001]. Corresponding values for epithelial attachment were 16.03% and 48.93% for the membrane and control defects, respectively [p < 0.005]. The mean volume of the new bone formed in the inter-radicular defects was 61.80% and 35.93% for the membrane and control defects, respectively [p < 0.02].The present study provided a biological rationale for high density polytetrafluoroethylen [d-PTFE, n-PTFE] as a barrier membrane for enhancement of the bone and cementum regeneration in grade II furcation defects subjected to regeneration therapy
ABSTRACT
Conventional risk factors for coronary artery disease and myocardial infarction do not explain all of the clinical and epidemiological features of the disease. Periodontal disease is a common bacterial and destructive disorder of oral tissues. Many studies demonstrate close association between chronic periodontitis and development of generalized inflammation, vascular endothelial injury, and atherosclesis. Periodontal disease has been convincingly emerging as an important independent risk factor for ischemic heart disease. A case - control study was carried out to assess the prevalence of periodontitis in patients with Acute myocardial Infarction [AMI] and evaluate the possible relationship between AMI and chronic periodontitis. A number of 160 patients, aged 35 to 70 years old, enrolled in the study. Eighty patients [43 men, 37 women] were examined four days after hospitalization due to AMI. Control group consisted of 80 persons [38 men, 42 women] with normal coronary angiography. The following periodontal parameters were examined: Plaque index [PI], gingiral index [GI], bleeding on probing [BOP], probing depth [PD], clinical attachment loss [CAL] and number of sites with CAL. The case, compared to control showed significantly worse results for some periodontal variables studied: The mean of PD and PD > 3 mm, CAL, and number of sites with CAL, had worse results compared to control despite similar oral hygiene and frequency of brushing. The confounding factors for the present study were found to be hypertension and diabetes. The association between periodontitis and acute myocardial infarction was significant after adjusting for conventional risk factors for AMI