Bone regeneration in aesthetic areas using titanium micromesh. Three case reports.

PURPOSE: An adequate bone volume for complete circumferential coverage of the implants is very important for obtaining a long-term success of oral implants. To avoid these problems various membranes and biomaterials were used, but soft tissue pressure could cause a membrane collapse toward the defect. The present work describes a ridge augmentation with titanium mesh shaped by adapting it to a bone defect in aesthetic areas. MATERIALS AND METHODS: Three patients with alveolar crest defects received three implants (Bone System, Milano, Italy) and the defects were filled with bone chips. The defects were covered with a titanium micromesh above which was positioned a resorbable membrane (Biogide, Geistlich, Wohlhusen, Switzerland). RESULTS: At the re-entry procedure the titanium micromesh appeared to be surrounded by a dense connective tissue with no clinical signs of inflammation. Clinically in all patients, no residual bone defects were observed, and a significant increase of the alveolar width or height was found. CONCLUSIONS: In conclusion the clinical results of the present study show that most certainly the space for the bone regeneration is one of the most critical factors in the success of the regenerative techniques.

Expansion of the alveolar bone crest with ultrasonic surgery device: clinical study in mandible.

The purpose of this paper was to document the application to the split-crest mandibular procedure in two stage in order to avoid cortical resorption due to periosteal detachment in buccal cortical bone of the alveolar crest. Twenty-two healthy patients with non-contributory past medical history (14 women and 8 men, all non-smokers, mean age 59 years, range 54-65 years) were included in this study. After buccal mucoperiosteal flap was followed by a sagittal corticotomy in the coronal area of the alveolar crest and a second sagittal corticotomy, but in a lower (basal) position and two vertical corticotomies in the buccal wall, using a ultrasonic surgery device (Surgysonic, Esacrom, Imola Italy). Adequate crest expansion was achieved without compromising cortical vascularisation by utilising a combination of scalpel, thin chisels and threaded osteotomes (Bone System, Milano, Italy). Postoperative results were assessed by panoramic and periapical radiographs. Ossification of the osteotomy lines was evident and could be observed as sites with increasing radiopacity on panoramic and periapical radiographs 3 months after implants insertion. No dehiscence of the mucosa was observed. No patient suffered from hypoaesthesia. The mean horizontal bone increase in coronal area was 5±3 mm. Mandibular ridge expansion using a split-crest technique that included grafting the implant sites with a ultrasonic surgery device is a viable therapeutic alternative for implant placement in this patient population.

Assessment of pain associated with insertion torque of dental implants. A prospective, randomized-controlled study.

This study investigated pain experience following dental implant placement in relation to insertion torque using questionnaires. A total 80 implants were placed in 20 patients. Each patient received 4 implants at different times. One implant was inserted and, then, after 40 days was placed the second implant, after 80 days was placed the third implant and after 120 days was placed the fourth implant. At each time the peri-implant bone levels were evaluated on intraoral radiographs taken with the paralleling technique. The implants were placed with a dynamometric key at 35N, 50N, 65N, 85N. Patients were asked to evaluate their pain experience during surgery, 24 hours after surgery, and at 2 days, 4 days, 1, 2, and 4 weeks after surgery on special pain assessment forms. A separate form was used for each time point. Pain was assessed using a descriptive numerical rating scale of 0 to 10, with 0 indicative of no pain and 10 representing the worst pain imaginable. Patients were instructed that a score of 1 to 3 was indicative of mild pain, 4 to 6 was indicative of moderate pain, and 7 to 10 was indicative of severe pain. A significant correlation pain scores and insertion torque was found between group III and group IV vs group II and group I during surgery, at 24 hours, 2 days, 4 days, 1 week, 2 weeks p ≤ 0.05. No statistical difference was found between group I vs. group II during surgery, at 24 hours, 2 days, 4 days, 1 week, 2 weeks p ≥ 0.05. In conclusion, elevated insertion torque values produces pain and resoption of the crestal bone around the implants.

Effects of bur wear during implant site preparation: an in vitro study.

BACKGROUND: Few studies have investigated the influence of drilling on bone healing. After the drilling of bone and placement of dental implants a sequence begins of cellular and molecular events which represents a combined response of wound healing. The bone healing around dental implants is a complex phenomenon and influences the proliferation and differentiation of pre-osteoblasts into osteoblasts, together with the activation of periosteal and endosteal lining cells, and initiates the production and mineralization of osteoid matrix followed by the organization of the bone-implant interface. The objective of this study is to quantify the temperature changes in cortical bone and marrow spaces during implant site preparation in bovine rib bone. A total 10 harvested bovine ribs and 6 10.5 x 3.5 new drills for implant insertion with external irrigation (Bone System, Milano, Italy) were used in this study. The implant sites were prepared with 10 mm long drills at 500 rpm under abundant external irrigation with saline solution at 37 degrees C. Each drill was used for 10, 30, 60, 90 and 120 implant site preparations; each drill was then observed under SEM for evaluation of the damage of the cutting edge after 10, 30, 60, 90 and 120 preparations. There was an higher and statistically significant increase in the temperature in the cortical bone; this increase in temperature increases with the number of the times of drill use. The drill wear seemed to play a major role in heat production and could explain the observed increased temperature of the bone.

Fluids and microbial penetration in the internal part of cement-retained versus screw-retained implant-abutment connections.

BACKGROUND: It has been recently observed that in implants with screw-retained abutments, in in vitro as well as in vivo conditions, bacteria can penetrate inside the internal cavity of the implant as a consequence of leakage at the implant-abutment interface. An alternative to screw-retained abutments is represented by implants that can receive cemented abutments. In this case, the abutment goes through a transmucosal friction implant extension (collar) and is cemented inside the internal hexagonal portion of the implant. The aim of the present research was to compare fluids and bacterial penetration in 2 different implant systems, one with cement-retained abutments (CRA) and the other with screw-retained abutments (SRA). METHODS: Twelve CRA dental implants and 12 SRA implants were used in this study. The research was done in 3 steps: scanning electron microscopic (SEM) analysis, fluid penetration analysis, and bacterial penetration analysis. RESULTS: 1) Under SEM it was possible to observe in the SRA implants a mean 2 to 7 micron gap between implant and abutment, while in the CRA implants, the gap was 7 micron. In the latter group, however, the gap was always completely filled by the fixation cement. All the spaces between abutment and implant were filled by the cement. 2) With SRA implants, it was possible to observe the presence of toluidine blue at the level of the fixture-abutment interface and the internal threads; the absorbent paper was stained in all cases. With CRA implants, the absorbent paper inside the hollow portion of the implants was never stained by toluidine blue. No penetration of toluidine blue was observed at the implant-abutment interface and inside the hollow portion of the implants. 3) In all the SRA implant assemblies, bacterial penetration was observed at the implant-abutment interface. No bacteria were detected in the hollow portion of the CRA implants. CONCLUSION: On the basis of the results obtained in the present study using 2 different implant systems, we conclude that CRA implants offer better results relating to fluid and bacterial permeability compared to SRA implants.

Localized ridge augmentation using titanium micromesh.

Guided bone regeneration (GBR) has been used recently for the regeneration of bone in conjunction with the placement of dental implants, for augmentation of resorbed alveolar crests, and to treat localized ridge deformities. Twenty-two patients with alveolar crest defects or peri-implant dehiscences participated in this study. Titanium implants were inserted, and the defects were covered with a titanium micromesh, above which was positioned an e-PTFE membrane. After healing, the 2 membranes were removed and a small specimen of the underlying tissues was retrieved with a small trephine. The postoperative healing was mostly uneventful, and only a few dehiscences with membrane exposure were observed. The space under the membranes was, in all patients, filled by a tissue with the macroscopic features of newly formed bone. No residual bone defects were observed and an increase of the alveolar width or height was observed. No untoward effects on bone regeneration were observed in the cases with membrane exposure. Histology showed that the underlying regenerated tissues were composed, in all cases, by newly formed bone. In conclusion, our results show that very satisfactory results concerning GBR techniques can be obtained even without the use of grafts under barrier membranes.

Surface analysis of machined versus sandblasted and acid-etched titanium implants.

Initially, implant surface analyses were performed on 10 machined implants and on 10 sandblasted and acid-etched implants. Subsequently, sandblasted and acid-etched implant cytotoxicity (using L929 mouse fibroblasts), morphologic differences between cells (osteoblast-like cells MG63) adhering to the machined implant surfaces, and cell anchorage to sandblasted and acid-etched implant surfaces were evaluated. Results indicated that acid etching with 1% hydrofluoric acid/30% nitric acid after sandblasting eliminated residual alumina particles. The average roughness (Ra) of sandblasted and acid-etched surfaces was about 2.15 microns. Cytotoxicity tests showed that sandblasted and acid-etched implants had non-cytotoxic cellular effects and appeared to be biocompatible. Scanning electron microscopic examination showed that the surface roughness produced by sandblasting and acid etching could affect cell adhesion mechanisms. Osteoblast-like cells adhering to the machined implants presented a very flat configuration, while the same cells adhering to the sandblasted and acid-etched surfaces showed an irregular morphology and many pseudopodi. These morphologic irregularities could improve initial cell anchorage, providing better osseointegration for sandblasted and acid-etched implants.

Guided bone regeneration using titanium grids: report of 10 cases.

In order to ensure an adequate space where new bone can be formed in guided bone regeneration (GBR), most surgeons fill bone defects with biomaterials. In this work we evaluated new bone regeneration in 10 patients using only a blood clot protected with titanium grids and non-resorbable membranes, without any filling material. A manual measurement of the size of the bone defect, using a plastic probe, was performed at 2 surgical steps. After 5 months of treatment, a biopsy was taken from each patient, fixed and embedded in PMMA, examined microradiographically and morphologically to evaluate the newly-formed bone. Our results showed a good repair of the defects by bone regeneration (about 85% overall), high mineral density of new bone around the implants after 5 months, and steady state deposition processes. These results in GBR, without filling material, appear very promising for implantology and reconstructive odontostomatology practice.