Paolo Trisi

Histomorphometric Evaluation of Six Dental Implant Surfaces After Early Loading in Augmented Human Sinuses

This study investigated the bone-to-implant contact (BIC) and osteoconductive capacity (OC) of 6 different implant surfaces after early loading in humans. Two implants with different surfaces were placed side-by-side in the grafted (n= 5) and nongrafted (n = 1) sinuses of 3 volunteers. Single-tooth restorations were delivered 60 days later. After 6 months of full occlusal loading, implants were retrieved in block sections for histomorphometric analysis. One implant (acid etched) placed in grafted bone failed when loaded. There were no other complications. In grafted bone, the microtextured surface achieved the highest BIC value (94.08%), followed by the oxidized (77.32%), hydroxyapatite (HA) (74.51%), sandblasted and acid-etched (51.85%), and titanium plasma-sprayed (TPS) (41.48%) surfaces. In native bone, the acid-etched surface achieved a higher BIC value (69.03%) than the HA surface (59.03%). The highest OC value in grafted bone was exhibited by the microtextured surface (34.31%), followed by the HA (28.62%), sandblasted and acid-etched (25.08%), oxidized (17.55%), and TPS (-20.47%) surfaces. The HA surface exhibited a higher OC value (30.39%) in native bone compared with the acid-etched surface (24.0%). As a whole, highest BIC and OC values were exhibited by the microtextured surface, and lowest values were exhibited by the TPS surface. All other surfaces demonstrated excellent BIC (>50%) but varied in OC (range = 17.55%-28.62%). These findings are tempered by the limited scope and sample size of the study and should be considered preliminary. More research is needed to determine the impact of implant surface texture on BIC and OC.

Histologic and biomechanical evaluation of the effects of implant insertion torque on peri-implant bone healing.

AbstractThe aim of this study was to evaluate histologically and biomechanically the peri-implant bone healing around implants placed with high torque after a follow-up of 8 and 12 weeks. A total of 12 implants were placed in the lower edge of the mandible of 2 sheep. In each sheep, 3 implants were placed with a low torque (<25 N · cm, LT group) as a control, and 3 implants were placed with a high insertion torque (maximum torque, HT group). The sheep were killed after 8 and 12 weeks of healing, and the implants were examined for removal torque, resonance frequency analysis, and histologic analysis.The mean insertion torque in the LT group was 24 N · cm, whereas it was 105.6 N · cm in HT. All the implants osseointegrated and histologic analysis showed similar aspects of the peri-implant bone tissue for both groups and both healing times. Mean removal torque values for LT implants were 159.5 and 131.5 N · cm after 8 and 12 weeks, respectively, whereas those for the HT were 140 and 120 N · cm at 8 and 12 weeks, respectively. Implant stability quotient values were 26.6 and 76 for the LT group and 74 and 76 for the HT group at 8 and 12 weeks, respectively.It could be concluded that high implant insertion torque does not induce adverse reaction in cortical bone and does not lead to implant failure.

Bone response to early orthodontic loading of endosseous implants.

This study evaluated the clinical, radiographic, and histologic responses of tissues surrounding implants loaded with a heavy force of 500g for 20xa0weeks after a 1-week healing period. Unilateral mandibular and maxillary alveolar ridges in the premolar areas of a male dog and the bilateral mandibular alveolar ridges of a female dog were chosen for implant placement. The control implants (1 in the maxilla, 3 in the mandible) were placed in these quadrants after a 12-week healing period following extraction. The test implants (1 in the maxilla, 3 in the mandible) were implanted in the same quadrants after a 4-month osseointegration period of the control implants. Abutments were attached to the control and test implants after a 1-week healing period for the test implants. Superelastic nickel-titanium coil springs, producing a force of 500g (≈5xa0N), were activated between control and test implants for 20xa0weeks. Light microscopic assessment revealed that all implants were well integrated with the bone. Histologic analysis showed no definitive differences between test and control implants in the corticalization of bone trabeculae. The mean bone-implant contact values of the control implants for compression and tension sides were 55.99% and 64.04%, respectively. In the test implants, the bone-implant contact value was 57.27% for the compression side and 62.96% for the tension side. Potential clinical applications of these radiologic and histologic results include the possibility of minimizing the healing duration, even for high orthodontic forces, and the possibility of postorthodontic use of these implants as abutments for supporting prosthetic reconstruction.