Nikolaos Dabarakis

Comparison of Acceptance, Preference, and Efficacy Between Jet Injection INJEX and Local Infiltration Anesthesia in 6 to 11 Year Old Dental Patients

Needleless devices have been developed to provide anesthesia without injections. Little controlled research has examined the acceptability of needleless devices in pediatric patients. The aims of the study were to compare childrens acceptance and preference for one type of needleless jet injection with classical local infiltration as well as to evaluate the efficacy of the needleless anesthesia. Eighty-seven nonfearful children with no previous experience of dental anesthesia were studied using a split-mouth design. The first dental procedure was performed with the classical infiltration anesthesia. The same amount of anesthetic was administered using the INJEX needleless device in a second session 1 week later, during which a second dental procedure was performed. Patients rated their acceptance and preference for the 2 methods, and the dentist recorded data about the need for additional anesthesia. More negative experiences were reported for the INJEX method. Most (73.6%) of the children preferred the traditional method. Among the 87 treatment procedures attempted following the use of INJEX, 80.5% required additional anesthesia, compared with 2.3% of those attempted following traditional infiltration. Traditional infiltration was more effective, acceptable, and preferred, compared with the needleless INJEX.

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.

Evaluation of Vertical Bone Regeneration Using Block and Particulate Forms of Bio-Oss Bone Graft: A Histologic Study in the Rabbit Mandible

The aim of the present study was to evaluate histologically vertical bone regeneration outcomes after using bovine bone graft material in block and granular forms. The buccal bony plates of the outer mandibles of 10 New Zealand rabbits received Bio-Oss blocks that were immobilized using orthopedic mini-plates, and another 10 received granular forms that were gently packed and stabilized into the custom-made perforated metallic cubes. The mean graft area (GA), new bone area (NBA), bone-to-graft contact (BGC), and maximum vertical height reached by the new bone development (MVH) were histometrically evaluated and showed no significant differences between 2 graft types. The new bone was observed mostly close to the basal bone and developed penetrating the trabecular scaffold in the form of seams that covered the intralumen surfaces of the block type graft, while in the granular graft type the new bone was observed to grow between the graft particles usually interconnecting them. Either form of Bio-Oss was capable of providing considerable vertical bone augmentation.

The Role of Temperature in the Action of Mepivacaine

The role of temperature in the action of local anesthetics was studied in 20 healthy young volunteers with plain 3% mepivacaine injected periapically twice in their maxillary first premolar, the first time with the solution at a temperature of 20 degrees C and the second time at 4 degrees C. The pulpal response was measured with a pulp tester every minute. The onset of pulp anesthesia was found to be of no statistical difference between 20 degrees C and 4 degrees C. On the other hand, mepivacaine at a temperature of 4 degrees C was found to have a statistically significant longer duration of action. Our conclusion is that the drop in temperature of mepivacaine from 20 degrees C to 4 degrees C provides a longer duration of pulpal anesthesia.

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°C it is significantly more potent on the establishment of anesthesia compared to the temperature of 36.5oC. In vivo, lidocaine at the temperature of 4oC is statistically significantly more effective in the establishment and the duration of anesthesia related to the temperature of 20°C.