Osseointegration of Osseotite and machined-surfaced titanium implants in membrane-covered critical-sized defects: a histologic and histometric study in dogs.

The texture of an implant's surface can influence the rate and extent of bone fixation as expressed by the amount of linear bone-to-implant contact (BIC). The purpose of this study was to compare the bone density and linear BIC between Osseotite and machined-surface implants placed in bony defects without graft material and covered by a membrane. Thirty 2 mm diameter, 10 mm length custom implants were prepared for this study having a 'split surface,' with one side having the acid-etched surface and the opposite side having a machined surface. Defects were created in the iliac wing of three adult mongrel dogs where a 6-mm-diameter drill was used to generate a 5-mm-deep defect. The implants were inserted into the center of the defect with 5 mm secured into the bone leaving 5 mm free in the defect with a 2 mm gap between the implant and surrounding bone. Expanded polytetrafluroethelyene membranes were placed over the defect sites stabilized with Biotack pins. The healing times were 2, 3, and 5 months. Histologic and histometric analysis showed significantly lower BIC in the defect region as compared with the portion of implant placed into native bone for both implant surfaces in all groups. There was no difference in BIC values at 2- and 5-month periods between the two surfaces in the regenerated area, while BIC values for Osseotite surfaces were significantly higher than the machined surfaces at 3 months' healing time. Changes in bone density, observed between the three groups, affected correspondingly the BIC values in both implant surfaces, the effect being more pronounced in the Osseotite surface.

Needle-less local anesthesia: clinical evaluation of the effectiveness of the jet anesthesia Injex in local anesthesia in dentistry.

OBJECTIVES: To clinically evaluate the jet injection Injex (Rösch AG Medizintechnik) using 2 different anesthetic solutions, and to compare the jet injection and the standard needle injection techniques. METHOD AND MATERIALS: Of the 32 patients in the study, 10 received mepivacaine 3% anesthetic solution by means of the jet injection technique, while the remaining 22 patients received lidocaine 2% with epinephrine 1:80,000 by the same method. The 14 patients in whom pulp anesthesia was achieved were selected for an additional evaluation of the pulp reaction using standard needle injection anesthesia. The differences between the 2 compounds with Injex were statistically evaluated by means of independent-samples t test analysis. The differences between subgroups receiving both jet injection and needle injection anesthesia were evaluated by means of paired t test analysis. RESULTS: The administration of mepivacaine 3% using Injex did not achieve pulp anesthesia in any of the 10 patients, although the soft tissue anesthesia was successful. The administration of lidocaine with epinephrine using Injex resulted in pulp anesthesia in only 14 patients; soft tissue anesthesia was observed in all patients of this group. There was no statistically significant difference between Injex and the needle injection technique in onset of anesthesia. However, the duration of anesthesia was significantly longer for the needle infiltration group than for the Injex injection group. CONCLUSION: The anesthetic solution should be combined with a vasoconstriction agent when the Injex technique is implemented.

Bone regeneration around implants using spherical and granular forms of bioactive glass particles.

PURPOSE: It has been reported that previous Biogran (3i Implant Innovations, Inc., Palm Beach Gardens, FL) can be converted in vitro into hydroxyapatite (Biogran II) to accelerate new bone formation. The purpose of this study was to evaluate the bone regeneration around implants placed in critical-sized defects in rabbit tibia using granular and spherical forms of Biogran II in regards to implant contact, bone-to-graft contact, bone graft area, and total bone volume. MATERIALS AND METHODS: Twelve adult New Zealand rabbits were used, offering 24 surgical sites (1 in each tibia), where 6-mm round defects were created allowing the homocentric insertion of a screw type experimental implant with Osseotite (3i Implant Innovations, Inc.) surface. Half of the defects (group A) were filled up with spherical and half (group B) with granular forms of Biogran II. Ossix (3i Implant Innovations, Inc.) membranes covered the surgical sites. RESULTS: The histological evaluation after 8 weeks showed new bone formation in both groups, without any statistically significant differences in regards to bone-to-implant contact, bone-to-graft contact, bone graft area, and bone volume. Both dissolution of the outer shell and inner silica gel of the particles were observed mostly in spherical particles. In addition, new bone formation within the protected pouch interconnected with the surrounding new bone was observed exclusively in spherical particles of Biogran II. CONCLUSION: Faster dissolution of both outer and inner portions of spherical particles of Biogran II led to better integration with the surrounding new bone during an 8-week period of healing.

The role of temperature in the action of local anesthetics: a double study in vitro and in vivo.

The purpose of this study was the examination of the role of temperature in the action of lidocaine via electrophysiological recordings on the sciatic nerve of the rat in vitro and in vivo. 20 Male Wistar rats were used in each type of experiment. In vitro, lidocaine shows no statistically significant difference regarding the onset of anesthesia but at the temperature of 25 degrees C it is significantly more potent on the establishment of anesthesia compared to the temperature of 36.5 degrees C. In vivo, lidocaine at the temperature of 4 degrees C is statistically significantly more effective in the establishment and the duration of anesthesia related to the temperature of 20 degrees C.

Clinical evaluation of immediate loaded upper anterior single implants.

Among the guidelines to be followed in the selection of patients who are suitable for treatment with dental implants, there must be accurate assessment and evaluation of the factors that will lead to a functionally long-lasting and aesthetically pleasing result. The latter, which includes the maintenance and development of hard and soft tissues, undoubtedly presents a significant challenge in clinical implantology. The purpose of this study was the clinical evaluation of the methods currently available for the aesthetic restoration of the anterior maxilla using single implants that were loaded immediately. Forty-three patients were treated over 2 years using single implants with immediate nonfunctional loading. The patients were divided into two groups, groups A and B (i.e., immediate implant installation and late implant installation, respectively). Guided bone regeneration techniques were performed in 10 patients in group A and three patients in group B and involved buccal fenestrations orbuccal dehiscence around the implants. The parameters studied were: 1) the anatomical requirements necessary in selecting such patients and the limitations that might affect (to a lesser or greater degree) the desired results; 2) the planning and application of surgical techniques, both with immediate and short-term delay postextraction implantation, as well as the placing of implants in areas with long-term dental loss; and c) the results, after radiologic and clinical follow-up visits every 6 months, for an overall period of 2 years. No implant failure was recorded, and the therapeutic procedures were considered completely successful in all cases, without significant radiographic peri-implant marginal bone loss (i.e., average bone loss in mm +/- SD, 0.75 +/- 1.05 in group A and 0.875 +/- 0.625 in group B) or significant clinical differences in peri-implant sulcus depth (average difference in mm +/- SD, 0.3 +/- 0.2 in group A and 0.4 +/- 0.375 in group B). In cases where guided bone regeneration techniques were applied, the results were considered successful and final, and the aesthetic results were deemed more satisfactory than was expected. The procedure was successful in all cases in terms of both osseointegration and aesthetics. The use of dental implants with nonfunctional loading in particularly sensitive aesthetic areas is recommended unreservedly, given the existence of the anatomical requirements, good initial stability, and the absence of extensive bone loss in the area receiving the implant. In addition, application of this treatment method leads, within a very short time, to a particularly successful aesthetic result, reducing the number of surgeries and the duration of treatment.

Effect of autogenous harvest site location on the outcome of ridge augmentation for implant dehiscences.

Treatment planning for the placement of an implant in a site with a thin crestal ridge should address the probability that a buccal dehiscence will result. The aim of the present investigation was to perform guided bone regeneration (GBR) around implants with buccal dehiscences and evaluate the outcomes of using autogenous bone grafts harvested from three different intraoral sites. Forty-six Osseotite implants, 4 mm in diameter, were placed in thin crestal ridges, resulting in an uncovered implant surface from the buccal aspect. The lengths of the buccal dehiscences ranged from 3 to 7 mm as measured from the implant cervix to the most apical extent of the uncovered threads. A standard GBR technique was carried out to augment the bone defect around the buccal implant surface immediately after implant placement. The cases were divided into three groups according to receipt of an autogenous bone graft from the ramus, tuberosity, or mandibular symphysis. In all cases, e-PTFE membranes were used to cover the grafted areas. Grafted sites were exposed after 6 months, membranes were removed, and residual distance between the implant cervix and most uncovered thread was recorded. All grafting materials were able to produce a certain degree of bone regeneration. In terms of bone change level, the three groups were not equal. The mandibular symphysis group exhibited the highest mean bone growth level, followed by the ramus group. The tuberosity produced the poorest result. Mandibular and ramus autogenous bone grafts represent the best choice in materials for GBR procedures around implants, while tuberosity bone grafts can be used as an alternative.

Osseointegration of Osseotite and machined titanium implants in autogenous bone graft. A histologic and histomorphometric study in dogs.

It has been shown that a roughened implant surface results in a higher percentage of bone to implant contact (%BIC) than a machined one. A modified implant surface using a dual thermo-acid etching process (Osseotite) has been introduced and evaluated clinically, mechanically and histologically. The aim of the present study was the histological evaluation of the %BIC between the Osseotite or machined surfaces and the autogenous bone graft. Twenty-two custom-made split-type 10-mm-long implants having two opposing surfaces (Osseotite and machined) were placed between the cranial and caudal dorsal iliac spine at the iliac wing of two adult mongrel dogs. An artificial bone defect was created leaving a 2 mm empty space around the coronal 5 mm of the implants, while the apical 5 mm was stabilized in the existing basal bone. The defects around the implants were filled with particulate autogenous bone graft, covered by an Osseoquest membrane, and left to heal for 5 months. All inserted implants showed a complete integration in the bone tissue. It was found that the resulting %BIC at the Osseotite surface was significantly higher than at the machined one in both regenerated (46.44+/-15.81% vs. 28.59+/-12.04%) and basal bone areas (32.32+/-15.09% vs. 17.25+/-7.40%). The findings of this study imply that the use of autogenous bone graft resulted in significantly higher %BIC values in the regenerated area than in the basal bone area itself, for both implant surfaces.