Bioglass associated with leukocyte-poor platelet-rich plasma in the rabbit maxillary sinus: histomorphometric, densitometric, and fractal analysis.

The objective of the present study was to evaluate the outcomes of autogenous bone graft (AB) and bioglass (BG) associated or not with leukocyte-poor platelet-rich plasma (LP-PRP) in the rabbit maxillary sinus (MS) by histomorphometric and radiographic analysis. Twenty rabbits divided into 2 groups (G1, G2) were submitted to sinus lift surgery. In G1, 10 MS were grafted with AB and 10 MS were grafted with BG. In G2, 10 MS were grafted with AB + LP-PRP and 10 MS were grafted with BG + LP-PRP. After 90 days, the animals were killed and specimens were obtained, x-rayed, and submitted to histomorphometric, radiographic bone density (RD) and fractal dimension analysis. Radiographic bone density mean values (SD), expressed as aluminum equivalent in mm, of AB, BG, AB + LP-PRP, and BG + LP-PRP groups were 1.79 (0.31), 2.04 (0.39), 1.61 (0.28), and 1.53 (0.30), respectively. Significant differences (P < 0.05) were observed between BG and AB, and BG + PRP and BG. Fractal dimension mean values were 1.48 (0.04), 1.35 (0.08), 1.44 (0.04), and 1.44 (0.06), respectively. Significant differences were observed between BG and AB, and AB + LP-PRP and BG. Mean values for the percentage of bone inside MS were 63.30 (8.60), 52.65 (10.41), 55.25 (7.01), and 51.07 (10.25), respectively. No differences were found. No correlations were observed among percentage of bone, RD and FD. Histological analysis showed that MS treated with AB presented mature and new bone formation. The other groups showed minor bone formation. Within the limitations of this study, the results indicated that at a 90-day time end point, AB yielded better results than AB + LP-PRP, BG, and BG + LP-PRP and should be considered the primary material for MS augmentation.

Effect of diabetes mellitus and insulin therapy on bone density around osseointegrated dental implants: a digital subtraction radiography study in rats.

OBJECTIVES: To evaluate the effect of diabetes mellitus (DM) and insulin therapy on bone density around osseointegrated dental implants by digital subtraction radiography (DSR). MATERIAL AND METHODS: Forty implants were placed in tibiae of 40 adult rats. After a healing period of 2 months, the animals were divided into four groups of 10 animals each: a 2-month control group, sacrificed at time (A), a diabetic group (D), an insulin-treated group (I) and a 4-month control group (C). During 2 months, group I received subcutaneous doses of insulin, whereas groups C and D received only saline. The animals in groups D, I and C were thereafter sacrificed. The glucose plasma levels (GPLs) were monitored throughout the experiment. Film radiographs were taken at implant surgery and on the day of sacrifice. The radiographs were digitized, and bone density in regions of osseointegration (OR) around the implants was evaluated by quantitative DSR between baseline and final images. Differences in shades of gray among the groups were assessed using ANOVA. RESULTS: GPLs were within normal range for groups A, C and I and higher for group D. There was a significant difference in mean gray shade values in the OR of subtraction images between groups D (122+/-7) and I (136+/-5) (P<0.05) while there were no significant differences between control groups A (128+/-13) and C (134+/-10) and the insulin group I. CONCLUSIONS: DM impaired bone density around osseointegrated dental implant. Further, insulin therapy maintained bone density in diabetic rats.

A survey of radiographic measurement estimation in assessment of dental implant length.

The aim of this study is to survey radiographic measurement estimation in the assessment of dental implant length according to dentists' confidence. A 19-point questionnaire with closed-ended questions was used by two graduate students to interview 69 dentists during a dental implant meeting. Included were 12 questions related to over- and underestimation in three radiographic modalities: panoramic (P), conventional tomography (T), and computerized tomography (CT). The database was analyzed by Epi-Info 6.04 software and the values from two radiographic modalities, P and T, were compared using a chi2 test. The results showed that 38.24% of the dentists' confidence was in the overestimation of measurements in P, 30.56% in T, and 0% in CT. On the other hand, considering the underestimated measurements, the percentages were 47.06% in P, 33.33% in T, and 1.92% in CT. The frequency of under- and overestimation were statistically significant (chi2 = 6.32; P = .0425) between P and T. CT was the radiographic modality with higher measurement precision according to dentists' confidence. In conclusion, the interviewed dentists felt that CT was the best radiographic modality when considering the measurement estimation precision in preoperative dental implant assessment.