Histomorphometric Evaluation of Bone Formation in Peri-Implant Defects Treated With Different Regeneration Techniques: An Experimental Study in a Rabbit Model.

PURPOSE: The aim of this study was to investigate the healing of artificially created peri-implant circumferential bone defects using three bone-regeneration techniques. MATERIALS AND METHODS: Rabbit tibias (24 rabbits), in which bone defects (9-mm diameter, 4-mm depth) were created and implant beds (3-mm diameter, 6-mm depth) were prepared in the middle of the created defects, were used as the experimental model. Dental implants (3.0 × 10 mm) were inserted, and the peri-implant bone defects were grafted with demineralized freeze-dried bone allograft (DFDBA) plus saline solution, DFDBA plus platelet-rich fibrin (PRF), or DFDBA plus rifamycin. After 4 weeks, the animals were euthanized and the implants with surrounding bone were removed. Undecalcified histomorphometric examinations with toluidine blue staining were performed, and the bone-to-implant contact (BIC) and percentage of new bone formation were evaluated. RESULTS: The BIC was 50.94% ± 24.39% in the DFDBA-plus-saline solution group, 60.07% ± 4.91% in the DFDBA-plus-rifamycin group, and 73.43% ± 3.86% in the DFDBA-plus-PRF group. The percentage of new bone formation at the defect area was 37.61% ± 1.70% in the DFDBA-plus-saline solution group, 48.51% ± 2.80% in the DFDBA-plus-rifamycin group, and 63.09% ± 2.10% in the DFDBA-plus-PRF group. In terms of new bone formation and BIC, the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups were significantly different from the DFDBA-plus-saline solution group. The difference between the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups was also statistically significant. CONCLUSIONS: The addition of PRF or rifamycin to DFDBA had a significant positive effect on bone healing in peri-implant bone defects. The DFDBA-plus-PRF group showed the highest percentages of new bone formation and BIC.

The influence of rifamycin decontamination on incorporation of autologous onlay bone grafts in rats: A histometric and immunohistochemical evaluation.

OBJECTIVE: Although it has been shown that rifamycin is an effective agent for bone graft decontamination, no information exists on the effects of rifamycin decontamination on bone graft incorporation. The aim of this study was to evaluate the influence of rifamycin decontamination on the incorporation of autologous onlay bone grafts quantitatively. DESIGN: In 30 rats, a standardized 5.0-mm-diameter bone graft was harvested from the right mandibular angle, contaminated with saliva, decontaminated with rifamycin solution, and augmented to the left as an onlay graft. Ten animals were sacrificed at 7, 14, and 21 days after surgery. In the control group (10 rats), the onlay grafts were neither contaminated nor decontaminated, and the rats were sacrificed at 21 days after surgery. Histological slides were prepared from each grafted site for both immunohistochemistry analysis (bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) antibodies) and histometric analysis. Images obtained from the graft incorporation area with the light microscope were transferred to a PC, and they were evaluated using Clemex PE 3.5 image analysis software. RESULTS: The grafts were fully incorporated in all specimens. The results showed that rifamycin decontamination has no detrimental effect on graft incorporation and the findings revealed a tendency for earlier revascularization and osteogenesis in the decontamination group. Data were analyzed using variance analysis and Tukey's test. CONCLUSIONS: Rifamycin decontamination has no detrimental effect on autogenous graft incorporation, and it can be used for graft decontamination with confidence.

Is it possible to anesthetize palatal tissues with buccal 4% articaine injection?

PURPOSE: The aim of this study was to evaluate the presence of probable diffused local anesthetic solution at and anesthesia of palatal tissues after buccal injection of 4% articaine hydrochloride (HCl) with 1:100,000 epinephrine or 1:200,000 epinephrine at the premolar and molar region. MATERIALS AND METHODS: Thirty volunteers received maxillary buccal injections of 4% articaine HCl with 1:100,000 epinephrine or 1:200,000 epinephrine bilaterally to the first premolar or first molar. Magnetic resonance images were obtained before and 5 minutes after local anesthetic injections, and a visual evaluation was done to determine the presence of local anesthetic solution at palatal tissues. Anesthesia of palatal tissues after buccal injection was assessed by needle-prick stimulation pain with a visual analog scale (VAS). The Kruskal-Wallis test was used for comparison of the VAS values. RESULTS: The visual evaluation of the magnetic resonance images did not show any signal change as an indicator of the presence of local anesthetic solution at the palatal region. Most of the volunteers described moderate or severe pain with needle-prick stimulation. The mean VAS score for needle-prick stimulation was 86.33 +/- 39.45 mm (1:100,000 epinephrine) and 87.0 +/- 36.28 mm (1:200,000 epinephrine) in the first premolar region and 57.20 +/- 46.69 mm (1:100,000 epinephrine) and 75.53 +/- 49.78 mm (1:200,000 epinephrine) in the molar region (P > .05). CONCLUSION: We could not establish the presence of anesthesia or 4% articaine HCl at the palatal tissues after buccal injection. Maxillary tooth removal without palatal injection requires further objective investigations.

Effects of simvastatin on mandibular distraction osteogenesis.

PURPOSE: The aim of this study was to evaluate the effects of local and systemic simvastatin application on distraction osteogenesis. MATERIALS AND METHODS: Eighteen New Zealand white rabbits underwent unilateral mandibular distraction osteogenesis. After 7 days of neutral fixation, 0.4 mm twice per day, distraction was performed for 10 days. Simvastatin was applied locally during the osteotomy phase with a gelatin sponge carrier and systemically during the distraction osteogenesis period by oral gavage. All animals were killed at the end of the consolidation period of 14 days. The distracted mandibles were harvested and evaluated by plain radiography, by peripheral quantitative computed tomography, and with histomorphometry. RESULTS: Radiographic evaluation with peripheral quantitative computed tomography showed that the area of the regenerate increased by 9.6% in the local simvastatin group and by 19.3% in the systemic simvastatin group as compared with the control group. In both experimental groups the density of the regenerate increased by 6.7% as compared with the control group. Statistical evaluation of radiographic data showed that all of these changes were not significant. Histomorphometric evaluation determined that there was no statistical difference among groups with regard to the ratios of bone tissue volume to fibrous tissue volume and bone tissue volume to marrow tissue volume. CONCLUSIONS: The results of this study suggest that simvastatin's effect on enhancing distraction regenerate is limited with the applied doses and methods.

Effect of local simvastatin application on mandibular defects.

Osteoinductive characteristics of bone grafts are important for enhancing osseous healing at grafted defect sites. The cholesterol-lowering drug simvastatin has been shown to stimulate bone formation by increasing the gene expression of bone morphogenetic protein-2 and vascular endothelial growth factor. The purpose of this study was to determine the effect of local simvastatin application on bone defect healing and compare the amount of new bone produced by simvastatin gelatin sponge graft with that produced by a gelatin sponge graft and with natural healing. Twenty-one bone defects at 3 mm diameter were created in the angulus mandible region of Wistar albino rats. In the experimental group, nine defects were grafted with simvastatin dissolved in water mixed with a gelatin sponge. In the control groups, eight defects were grafted with water mixed with a gelatin sponge alone (active control) and six were left empty (passive control). Animals were killed on day 14 and the defects were prepared for radiologic and histologic assessment. Density of the regenerate was evaluated by peripheral quantitative computed tomography. The density of the experimental group was 240% more than the passive control group and 190% more than the active control group (P < 0.01). Histologic examination also showed more new bone formation in the experimental group than control groups. In conclusion, the simvastatin gelatin sponge enhanced bone defect healing in the mandible of rats.

Infection-related inferior alveolar and mental nerve paresthesia: case reports.

Nerve injury can be related to mechanical, chemical, and thermal factors. Infection-related paresthesia is usually related to mechanical pressure and ischemia associated with the inflammatory process. Another cause of paresthesia could be the toxic metabolic products of bacteria or inflammatory products released following tissue damage. This article presents cases of inferior alveolar and mental nerve paresthesia caused by an infected impacted tooth, an infected cyst, and periapical infection. The possible pathophysiologic mechanism of nerve injury, therapy, and prognosis for recovery are also discussed.

Utilisation of personal protective equipment in dental practice.

OBJECTIVE: To investigate personal protective equipment such as gloves, mask and protective eye wear used in dental practice in Turkey. DESIGN: An e-mail based self-report questionnaire was sent to dentists during 2002. PARTICIPANTS: Dentists in Turkey. RESULTS: 574 dentists aged 22-69 years responded. Thirty-six questionnaires were not included in the results. The results of the present study indicate that a high proportion of younger dentist respondents are using personal protective equipment in accordance with guidelines. More dentists use personal protective equipment for high-risk patients. The percentage of dentists using protective eyewear was low considering the general recommendations. CONCLUSION: The present study indicated that gloves and masks are used by a high proportion of the respondents. Further education may be appropriate in protective eyewear.

An unusual buccal adenoma with extensive squamous metaplasia and cyst formation.

Salivary gland tumors are the second most common neoplasm of the mouth following squamous cell carcinoma, and account for a significant proportion of oral tumors. We report a case of an unusual adenoma that presented as a solitary intraoral buccal mass in a 28-year-old male patient. The tumor was intrepreted as an unusual pleomorphic adenoma because of the absence of connective tissue changes and presence of metaplastic epithelial change which is an occasional finding of such tumors. Moreover, the presence of cystic structures with papillary infoldings filled with some crystals and pearl-like keratinized material were also salient features.

Osteoblastoma of the mandible with root resorption: a case report.

This article reviews the clinical behavior, histologic features, differential diagnosis, and treatment of a benign osteoblastoma. Benign osteoblastoma is a rare tumor constituting 1% of all primary bone tumors. Only 15% of osteoblastomas occur in the skull and jaw bones. The most common clinical presentation is a painful or tender swelling. A case is presented of a 21-year-old female who had noted discomfort for approximately 2 years, and the pain was not relieved by any analgesic. The choice of treatment was local excision and curettage. In this case, root resorption of the adjacent tooth, which is not a characteristic behavior of osteoblastoma, is seen.

Pulpal blood flow: effects of corticotomy and midline osteotomy in surgically assisted rapid palatal expansion.

INTRODUCTION/PURPOSE: Surgically assisted rapid palatal expansion is used for the management of transverse maxillary deficiency in the early permanent dentition. The success depends on the maintenance of an adequate blood supply to the mobilized segments. The aim of this study was to assess the effects of corticotomy and midline osteotomy on the tooth pulpal blood flow. MATERIAL: Laser Doppler flowmetry was applied as a non-invasive and reliable technique for the assessment of pulpal blood flow in the maxillary centrals, canines and first molars. The blood flow was investigated pre- and postoperatively, on the first, third, and seventh postoperative days bilaterally in 13 cases. RESULTS: The results of this study indicate that ischaemia of the pulp can occur following osteotomy at the Le Fort I level. CONCLUSION: Corticotomy 5mm above the dental apices and separating the midpalatal suture did not have any serious effect on pulpal blood flow in this study.