Immunohistochemical analysis of Ki-67 in dental follicle of asymptomatic impacted third molars.

INTRODUCTION: Dental follicle (DF) is an ectomesenchymal tissue that surrounds the developing tooth germ and contains precursor cells for cementoblasts, periodontal ligaments and osteoblasts. Radiographically, the DFs are seen as semicircular radiolucencies around unerupted teeth. However, if the DFs are larger than 2.5 mm, they are considered to be a pathological change. AIMS AND OBJECTIVES: The purpose of this study is to assess the cell proliferation activity of DF surrounding an asymptomatic impacted third molar teeth using the Ki 67 proliferation marker and to evaluate the variation of cell proliferation depending on the age factor. MATERIALS AND METHODS: Forty-four specimens of DFs associated with impacted mandibular third molars fully covered by mucosa or bone were surgically removed from 44 patients. The patients were divided into 2 age groups. Twenty of forty-four DFs were between 18 and 29 years (Group 1) and 24 were 30 years and above (Group 2). Ki-67 immunostaining was evaluated in epithelial component of the DFs. RESULTS: Ki 67 expression was found to be 60% in Group 1 and 75% in Group 2. Statistically significant differences were found among the two groups in both the basal layer and the supra-basal layer. CONCLUSION: This study shows that DFs have more proliferative potential in older people as compared to the young and squamous metaplasia may be an early sign of developing lesions of odontogenic origin. Therefore, clinicians should be aware that histopathological changes could be found in DFs without clinical and radiographic alterations.

Determination of defensin HNP-1 in human saliva of patients with oral mucosal diseases.

Saliva is a biological fluid that is easily obtainable and that can give useful information both in systemic and oral diseases. In this study, a chromatographic method was applied to determine the amount of defensin HNP-1 in human saliva of patients with oral mucosal diseases before and after treatments and compared with controls. Defensin human neutrophil peptide-1 (HNP-1) was identified and confirmed. The concentration of HNP-1 in saliva was determined by comparing the area of eluted HNP-1 with that of HNP-1 standard. Linear calibration range of defensin HNP-1 was 0.10 to 0.90 µg/10 µL with R(2) values of 0.996. The concentrations of HNP-1 in the saliva of patients with oral lichen planus, Behçet's disease, and recurrent apthous stomatitis were 33.6 ± 10.6, 15.5 ± 7.6, and 36.3 ± 9.5 µg mL(-1) (mean ± S.D.), respectively. The salivary defensin-1 concentration was significantly higher in patients with oral mucosal diseases than in healthy volunteers; furthermore, in patients with oral mucosal diseases, the concentration was significantly higher before treatment than after treatment.

Correction of Mandibular Retrognathia and Laterognathia by Distraction Osteogenesis: Follow up of 5 cases.

This article evaluates the use of distraction osteogenesis in the treatment of mandibular retrognathia and laterognathia and the long term treatment results of the patients treated with this technique. The procedure was carried out in 5 subjects (3 males and 2 females, mean age 18.4 years) aged between 14 years and 27 years. In patients treated with bilateral mandibular distraction, it was observed that the ANB angle decreased by a mean of 5 degrees , the mandibular corpus length increased by a mean of 14.5 mm and the overjet decreased by a mean of 12.2 mm after treatment. In patients treated with unilateral mandibular distraction, a mean of 3.5 degrees reduction was achieved in ANB angle, the mandibular corpus length increased by a mean of 5.5 mm and a mean of 7 mm correction was achieved in relation to craniofacial midline with treatment. One of these patients showed an increase of 10 mm in ramus height on the affected side and a decrease of 5 degrees in gonial angle whereas the other one showed an increase of 12.5 degrees in gonial angle and an increase of 11 mm in ramus height on the affected side after treatment. The most significant long term relapse was observed in one of the patients treated with bilateral mandibular distraction. Long term relapse seen in the rest of the patients was within clinically acceptable limits. It can be concluded that distraction of the deformed mandible is a feasible and effective technique for treating mandibular retrognathia and laterognathia. However, it must be borne in mind that accurate placement of the distractors and determining the correct distraction vector are crucial factors that have an influence on long term clinical success.

Histological evaluation of the effects of bioglass, hydroxyapatite, or demineralized freeze-dried bone, grafted alone or as composites, on the healing of tibial defects in rabbits.

OBJECTIVES: To compare the effectiveness of bioactive glass (BG), natural hydroxyapatite (HA), and demineralized freeze-dried bone (DFDB) in bone defects. METHODS: All animal experiments were conducted in Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey, under the Selcuk University Guidelines for Animal Experimentation, in 2005. Eighteen New Zealand rabbits were used for the experiment. Four cavities were prepared on right and left tibias. The cavities on the right tibia were filled with either BG, HA or DFDB. One cavity was left empty as a control. The cavities on the other tibial bone were grafted with HA(+)BG, HA(+)DFDB, BG(+)DFDB and HA(+)BG(+)DFDB composites. Histological examinations were performed at first, third, and sixth postoperative months. RESULTS: According to histomorphometric findings, the mixture containing HA(+)BG(+)DFDB obtained the best histological results (p<0.05). CONCLUSION: The composite graft of HA, BG and DFDB is more effective than when used as individual agents.

Effects of mandibular symphyseal distraction osteogenesis on mandibular structures.

INTRODUCTION: The purpose of this study was to evaluate the effects of mandibular symphyseal distraction osteogenesis on dental and mandibular skeletal structures with a tooth- and bone-borne distraction device. METHODS: The sample comprised 20 patients, ranging in age from 15.8 to 23.3 years (mean, 20.1 +/- 2.3 years) at the start of treatment. The distraction device was activated 1 mm per day. The device was usually maintained in position about 90 days after surgery. Records were obtained at the start of treatment, at the end of distraction (11.4 +/- 2.2 days after surgery), and at follow-up periods (24.1 +/- 4.2 months after surgery). The records included posteroanterior cephalograms and study casts. The data were analyzed statistically by using the repeated measure analysis of variance and paired t test. RESULTS: Posteroanterior cephalometric analysis demonstrated no significant changes in bigonial widths and ramal angles at the end of distraction period. On the other hand, bimolar widths were significantly increased, whereas bicondylar widths were markedly decreased. The dental cast analysis indicated that the maximum amount of increase was found between the mandibular canines, and the widening effect gradually decreased from the mandibular canines to the second molars. The follow-up data confirmed that the treatment results were stable. CONCLUSIONS: The long-term findings indicate that mandibular symphyseal distraction osteogenesis is an efficient nonextraction treatment alternative for mandibular dental crowding to increase mandibular skeletal and dental arch widths.

Microscopic evaluation of mandibular symphyseal distraction osteogenesis.

The purpose of this study was to evaluate microscopically the newly formed hard tissue after a consolidation period of mandibular symphyseal distraction osteogenesis (MSDO). Sixteen patients underwent MSDO treatment. After a latency period of seven days, the distraction device was activated by the patient once in the morning and once in the evening, for a total of one mm per day for a mean 10.1 +/- 2.8 days, and the mean opening of the device was 8.1 +/- 1.7 mm. The device was usually maintained in position approximately 90 days after surgery. After the completion of the distraction period, the lower anterior teeth were bonded and tooth movement into the distraction site was initiated. After a consolidation period, second surgery was performed to remove the distraction devices. During the second surgery, hard tissue biopsies were taken on the apical region of the two central incisors and the left canine. The samples were fixed in 10% buffered formalin and decalcified in 3% HNO(3) solutions. New bone formation was present within the distraction gap immediately after the consolidation period. The cellular construction was more irregular in the distraction sections than in the normal bone sections. The newly distracted area was not complete immediately after the consolidation period. Furthermore, the newly formed bone had a membranous structure, which indicates continual maturation. Bone exposed to stretching forces undergoes new bone formation, and the newly formed bone is of a membranous type also named as a woven type.