[Study on bone volume harvested from the implant sites with different methods].

OBJECTIVE: To compare the volume of autogenous bone particles harvested utilizing different techniques and various implant systems during implant surgery, and to determine the advantageous method to collect autogenous bone particles. METHODS: Homogeneous epoxy resin simulated jaw bone model was enrolled. Bicon, Bego implant systems and Straumann tissue level implant systems were utilized. The two techniques were investigated. One method was low-speed drilling (50 r/min) without water irrigating, and the other one was drilling with cold water irrigating to the ideal depth, then closing the water and drilling out with low speed (50 r/min). The bone particles in the drill groove and implant beds were collected. The volumes of the bone harvested were compared between the different techniques and also among the three implant systems, then they were compared with the volume of the bone harvested by the special bone drill. The sample size of each sub-group was 10. The bone particles were weighed by electronic balance after drying. RESULTS: The harvested bone volume between the latch reamers and hand reamers of Bicon system with the first method was not significantly different. When the same size implant bed was prepared, the volume of the bone particles produced during the implant surgery with low-speed drill without water was significantly higher than that with the other method no matter Bicon [3.5 mm×10 mm hole for example (28.42±6.04) mg vs. (6.30±2.51) mg, P<0.001] or Bego system [2.8 mm×10 mm hole for example (28.95±5.39) mg vs. (4.61±3.39) mg, P<0.001] was used, and the ratio of bone volume between the first method and the second one was approximately 3.3 to 7.0 times. When using the second method to prepare the similar size implant bed, the bone volume was not significant different among Bicon, Bego and Straumann implant systems [Bicon (9.90±3.42) mg, Bego (8.70±4.09) mg, and Straumann (10.56±5.66) mg, P=0.69]. When preparing a 5 mm-diameter-10 mm-length hole with Bicon implant system and a 4.7 mm-diameter-10 mm-length with Bego implant system, the bone quantity harvested from each group was less than that harvested by special bone drill from Neo Biotech [Bicon (82.54±12.26) mg, Bego (85.07±12.64) mg vs. Neo Biotech (96.78±13.19) mg, P<0.05]. CONCLUSION: More autogenous bone can be harvested from implant beds by preparing with low-speed rolling without water than the method with water irrigation. When utilizing the same preparing method, the implant system has no impact on the volume of the bone harvested.

[Radiography study on osteotome sinus floor elevation with placed implant simultaneously with no graft augmentation].

OBJECTIVE: To investigate the change of endo-sinus bone height and bone volume in osteotome sinus floor elevation (OSFE) without bone graft but placing implants simultaneously by using cone beam computed tomography (CBCT) and three dimensional analysis, and to find the impacting factors on endo-sinus bone augmentation. METHODS: OSFE was performed in 38 edentulous patients with missing teeth at posterior maxillary region, and 44 implants were placed and referred for OSFE using no graft materials. CBCT was performed pre-surgery and 9－68 months post-surgery when the patients encountered another implant surgery. The gained bone height at mesial, distal, buccal and palatal sites around the implant in sinus were measured, volumetric measurements of the endo-sinus gained bone volume (ESGBV) in the elevated region were calculated by Mimics software. Univariate analysis and multiple linear regression were performed to investigate the impacting factors on the gained bone height and ESGBV. Marginal bone loss was recorded according to the periapical radiography after implant restoration. RESULTS: The mean residual bone height (RBH) pre-surgery was (3.41±1.23) mm, the mean protruded length (PL) into sinus of implant post-surgery was (3.41±1.28) mm, the mean endo-sinus gained bone height was (2.44±1.23) mm at distal sites, (2.88±1.20) mm at mesial sites, (2.83±1.22) mm at buccal sites and (2.96±1.16) mm at palatal sites, the mean endo-sinus gained bone height at distal sites was significantly lower than the other three sites (P < 0.05). The average endo-sinus gained bone height was (2.78±1.13) mm. The mean ESGBV was (122.15± 73.27) mm3. Univariate analysis showed the more RBH, the less bone height gained in sinus, which existed at buccal, lingual, mesial and distal sites (P < 0.001), and the more RBH, the smaller ESGBV gained (P=0.012). The ESGBV was significantly higher in the subjects whose bone generation period was more than 24 months than those whose bone generation period less than 24 months (P=0.034). The more PL, the more bone height and ESGBV gained (P=0.008). Multivariate analysis showed after adjusting factors of gender, age, smoking, width of sinus floor, thickness of sinus membrane pre-surgery, diameter and length of the implant, PL and bone generation period was positively correlated with mean endo-sinus gained bone height and ESGBV, while RBH negatively correlated with mean endo-sinus gained bone height. During the follow-up, the mean marginal bone loss was 0 (0－1.41) mm and all the implants loaded successfully. CONCLUSION: OSFE without bone graft but with placed implant simultaneously can increase endo-sinus gained bone height and ESGBV. RBH, PL and bone generation period are the significant factors impacting endo-sinus bone augmentation.

Arg555Gln mutation of TGFBI gene in geographical-type Reis-Bücklers corneal dystrophy in a Chinese family.

OBJECTIVE: Mutations of the transforming growth factor ß-induced (TGFBI) gene were studied in a Chinese family with Reis-Bücklers corneal dystrophy (RBCD). METHODS: Six family members with RBCD and six unaffected family members were investigated. The pedigree showed a typical dominant inheritance pattern. Genomic DNA was extracted from peripheral leucocytes from all study participants. Exons 4, 12 and 14 of the TGFBI gene were analysed using polymerase chain reaction, and standard automated sequencing was performed. Corneal tissue sampled from the proband during phototherapeutic keratectomy was examined using transmission electron microscopy (TEM). RESULTS: A typical geographical pattern of fine opacities in Bowman's layer of the cornea was seen in all six patients on slit-lamp examination. An Arg555Gln (R555Q) mutation of the TGFBI gene was identified in all six patients but was absent in all unaffected family members. TEM revealed rod-shaped bodies in Bowman's layer of the cornea. CONCLUSIONS: In this Chinese family an R555Q mutation of the TGFBI gene was associated with RBCD. As the RBCD phenotype is usually associated with an R124L mutation, this novel genotype-phenotype correlation may prompt further investigation of Bowman's layer corneal dystrophy.