Implant Bed Preparation Research Articles

Effects of irrigation temperature on heat control in vitro at different drilling depths

Thermal injury during implant bed preparation has a major influence on implant osseointegration and survival. This study investigated the effectiveness of the temperature of the saline solution used for heat control during drilling. Fresh frozen edentulous segments of bovine mandibles were sectioned into 12 x 6 cm pieces. Thermoresistors were placed 0.5 mm from the drilling cavity walls, at depths of 3, 7, and 12 mm. Signals from the three thermoresistors were analyzed using ORIGIN 5.0 software. The maximum temperatures during drilling without irrigation were 50.9, 47.4, and 38.1 degrees C at depths of 3, 7, and 12 mm, respectively. With irrigation using saline at 25 and 10 degrees C, the maximum temperatures at a depth of 12 mm were 37.4 and 36.3 degrees C, respectively. All other measurements with both 25 and 10 degrees C saline were below body temperature. This experimental in vitro study showed that more heat was generated in the superficial part of the drilling cavity than at the bottom. Therefore, external irrigation at room temperature can provide sufficient cooling during drilling. Lower temperature saline was more effective in cooling the bone, and irrigation of the site should be continued between the drilling steps.

Immunohistochemical characterization of guided bone regeneration at a dehiscence‐type defect using different barrier membranes: an experimental study in dogs

The aim of the present study was to evaluate immunohistochemically the pattern of guided bone regeneration (GBR) using different types of barrier membranes. Standardized buccal dehiscence defects were surgically created following implant bed preparation in 12 beagle dogs. Defects were randomly assigned to six different GBR procedures: a collagen-coated bone grafting material (BOC) in combination with either a native, three cross-linked, a titanium-reinforced collagen membrane, or expanded polytetrafluorethylene (ePTFE), or BOC alone. After 1, 2, 4, 6, 9, and 12 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin - OC, transglutaminase II - angiogenesis) and histomorphometrical analysis [e.g., bone-to-implant contact (BIC), area of new bone fill (BF)]. In general, angiogenesis, OC antigen reactivity, and new bone formation mainly arose from open bone marrow spaces at the bottom of the defect and invaded the dehiscence areas along the implant surface and BOC. At 4 weeks, membranes supporting an early transmembraneous angiogenesis also exhibited some localized peripheral areas of new bone formation. However, significantly increasing BIC and BF values over time were observed in all groups. Membrane exposure after 10-12 weeks was associated with a loss of the supporting alveolar bone in the ePTFE group. Within the limits of the present study, it was concluded that (i) angiogenesis plays a crucial role in GBR and (ii) all membranes investigated supported bone regeneration on an equivalent level.

Guided bone regeneration at dehiscence-type defects using biphasic hydroxyapatite + beta tricalcium phosphate (Bone Ceramic ®) or a collagen-coated natural bone mineral (BioOss Collagen ®): an immunohistochemical study in dogs

The aim of this study was to immunohistochemically investigate bone regeneration following application of either hydroxyapatite + beta tricalcium phosphate (BCG) or a collagen-coated natural bone mineral (BOC) in combination with a collagen membrane at dehiscence-type defects in dogs. Standardized buccal dehiscence defects were surgically created following implant bed preparation in six beagle dogs. Defects were randomly filled with either BOC (BioOss Collagen ®) or BCG (Bone Ceramic ®) according to a split-mouth design, and covered with a native porcine derived collagen membrane (BioGide ®). After 1, 4 and 9 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin) and histomorphometrical analysis (residual defect length, new bone-implant contact, area of new bone fill, percentage of osseointegrated bone-graft particles). Both groups revealed a significant decrease in mean residual defect length, and increases in mean new bone–implant contact, bone fill and percentage of osseointegrated bone-graft particles after 4 and 9 weeks of healing. Remaining BCG and BOC granules were completely integrated into a secondarily formed network of spongiosa, but there was no osteoclastic activity at the surface of either type of bone-graft particle. Both BCG and BOC may provide an osteoconductive scaffold to support guided bone regeneration procedures at dehiscence-type defects.

Influence of implant bed preparation using an Er:YAG laser on the osseointegration of titanium implants: a histomorphometrical study in dogs

The aim of the present study was to evaluate the influence of implant bed preparation using an Er:YAG laser on the osseointegration of titanium implants. A total of 24 implant channels were prepared in the lower jaws of four beagle dogs using (i) an Er:YAG laser device (ERL), or (ii) conventional drills (CD) according to a split-mouth design (n=6 implant channels per animal). Three screw-type titanium implants of different manufacturers were randomly inserted in both groups to evaluate submerged healing at 2 and 12 weeks. Width of the peri-implant gap (WPG) and bone-to-implant contact (BIC) were assessed histomorphometrically. There were no identifiable signs of any thermal side effects in both groups. ERL osteotomy frequently resulted in wide peri-implant gaps particularly in the apical area of the implant supporting bone. The following mean scores were assessed (+/-s.d.): WPG (2 weeks): ERL: 0.89+/-0.48 mm; CD: 0.27+/-0.09 mm (P<0.001 respectively); BIC (2 weeks): ERL: 34.5+/-7.76%; CD: 48.5+/-11.08% (P<0.001 respectively); BIC (12 weeks): ERL: 64.1+/-8.97%; CD: 68.94+/-11.23% (P>0.05 respectively). Within the limits of the present study, it was concluded that ERL may represent a promising tool for implant bed preparation.

Computer-guided flapless transmucosal implant placement in the mandible: A new combination of two innovative techniques

To assess whether computer-guided flapless transmucosal implant bed preparation without mucosal punching allows placement of dental implants in edentulous mandibles. Twenty patients with fully edentulous mandibles (11 male; 9 female) were included in the study. Each patient was scheduled to receive 4 screw-shaped Ankylos (Dentsply Friadent, Mannheim, Germany) implants in the interforaminal region. The StealthStation Treon navigation system (Medtronic, Minnesota, MN) was used for computer-guided drilling. Using conventional implant drills the mucosa was penetrated without flap elevation or mucosal punching. The study protocol did not allow direct visualization of the bone surface during surgery. For 78 implants (97.5%) the preoperative plan could be transfered to the patient by intraoperative navigation with a mean deviation of 0.9 mm (Implant tip 0.8 +/- 0.6 mm; coronal implant end 1.1 +/- 0.7 mm) as measured by comparing pre- and postoperative computerized tomography images. Two implants (2.5 %) were not primarily stable and failed to osseointegrate. Computer-guided transmucosal interforaminal implant placement without mucosal punching is a precise and predictable procedure. It is, however, not yet suitable for all bone morphologies. Future developments may include miniaturization of hardware and simplification of the drilling procedure.

Peri-implant alveolar bone loss with respect to bone quality after use of the osteotome technique: results of a retrospective study.

Knife-edge configurations or non space-maintaining defects of the alveolar ridge limit the indications for implant-prosthetic rehabilitation. If ridge expansion is required, bone splitting and bone spreading techniques may be applied. Summers introduced a modified approach for ridge expansion by osteotome technique. The principles of this nonablative implant bed preparation technique are lateral and apical bone relocation and condensation. The peri-implant alveolar bone loss after use of the osteotome technique was evaluated radiographically with respect to the bone quality in 22 patients with 22 implants. Differences between the alveolar crest and the implant shoulder in radiographs obtained immediately after implant insertion, after the end of unloaded healing period and after different periods of functional loading were calculated. The osteotome technique was used in bone quality classes 2 and 3, respectively, according to the Lekholm and Zarb classification. Two implants failed. Significant differences were found between the bone levels after implant insertion and at the end of the healing period as well as after functional loading (P = 0.028). The bone quality was significantly correlated (r = - 0.505; P = 0.023) with the change of the peri-implant marginal bone height level 6 months after the implant installation. The present data indicate the importance of bone quality evaluation before application of the osteotome technique.

Changes in the alveolar ridge level in implantation using the osteotomy technic. Retrospective studies

Due to a configuration defect, the use of membrane-guided bone regeneration or alveolar ridge extension is required. The bone splitting and bone spreading technique was modified by developing the osteotome technique and the osteotome kit (Summers 1994). Lateral and apical bone displacement and condensation are the principles of this nonablative implant bed preparation technique. Estimation of the periimplant bone level is one of the important prognostic parameters for estimating implant survival. The level of the alveolar crest near implants which were inserted using the osteotome technique was investigated by measuring the differences between the alveolar crest and the implant shoulder in postoperative radiographs after implant insertion and after uncovering the implants in 17 patients. The osteotome technique was used in bone quality D2 and D3 according to the classification by Misch (1993). Significant differences were found between the bone levels after implant insertion and implant uncovering. A significant correlation (r = 0.5466; P = 0.023) was calculated between the differences of the marginal bone level at implantation and uncovering time and the bone quality. There should be strict indications for using the osteotome technique for evaluating the bone quality found at the implant site to optimize the long-term prognosis of the implants.