Fissure Bur Research Articles

Mastering interproximal stripping: with innovations in slenderization.

ABSTRACTCrowding and irregularity remain a consistent problem for children. Management of space problems continues to play an important role in a dental practice. It also represents an area of major interaction between the primary provider and the specialists. Proximal stripping is routinely carried out to avoid extraction in borderline cases where space discrepancy is less and in cases where there is a discrepancy between the mesio- distal width of maxillary and mandibular teeth to satisfy Bolton ratio. Proximal stripping is carried out using of metallic abrasive strip, safe sided carborundum disk, or with long thin tapered fissure burs with air rotor.The use of rotary cutting instrument can harm the pulp by exposure of mechanical vibration and heat generation (in some cases). Whereas, the large diameter of the disk obstructs vision of the working area. Also fracturing away a portion is a common problem with disk. Tapered fissure burs cut the tooth structure as the width of bur or overcutting may occur of the tooth structure due to high speed. The use of metallic abrasive strip is the safest procedure amongst the above. The strip can be placed in the anterior region without any difficulty but using it in the posterior region is difficult as, it is difficult to hold it with fingers while stripping the posterior teeth.To avoid this inconvenience here with a simple and economical way of fabricating strip holder from routine lab material is presented.Clinical implications: Proper management of space in the primary and mixed dentitions can prevent unnecessary loss in arch length. Diagnosing and treating space problems requires an understanding of the etiology of crowding and the development of the dentition to render treatment for the mild, moderate and severe crowding cases. Most crowding problems with less than 4.5 mm can be resolved through preservation of the leeway space, regaining space or limited expansion in the late mixed dentition. In cases with 5 to 9 mm of crowding, some can be approached with expansion after thorough diagnosis and treatment planning. Most of these cases will require extraction of permanent teeth to preserve facial esthetics and the integrity of the supporting soft tissue. Sequential proximal stripping is routinely carried out to avoid extraction in borderline cases where space discrepancy is less and reserved for treatment of mild tooth-size/arch-size discrepancies.How to cite this article: Sharma NS, Shrivastav SS, Hazarey PV. Mastering Interproximal Stripping: With Innovations in Slenderization. Int J Clin Pediatr Dent 2012;5(2):163-166.

Effect of various techniques of tetracycline hydrochloride demineralization on root dentin surface: A scanning electron microscopic study

Aim : To evaluate the in-vitro effect of various techniques of Tetracycline Hydrochloride application on root dentin surface at different magnifications of scanning electron microscopic (SEM). Materials and Methods : Twenty human teeth were collected and stored in distilled water after soft tissue removal using hand instruments. The apical third of each root was removed remaining mid-third region was sectioned longitudinally through the root canal following removal of its cementum with a tapered fissure bur. The dentin blocks were divided into 4 groups having 5 samples in each group. A tetracycline hydrochloride solution was prepared by adding the contents of one 500 mg capsule to 5 ml of distilled water. The application time of the tetracycline hydrochloride was 5 minutes. After the treatment of the root surfaces, the samples were fixed in 2.5% glutaraldehyde prepared in phosphate buffer (pH 7.3) for 24 hours at 4°C and prepared for SEM. Mean and standard deviation were estimated from the samples for each study group. Mean values were compared by either ONE-WAY ANOVA with Tukey - HSD procedure. Results : All technique of tetracycline application shows removal of smear layer and exposure of dentinal tubule orifices. Burnishing technique showed significant difference than immersion technique and saturation technique. Conclusion : In view of these present findings, tetracycline hydrochloride as a root conditioner may be evaluated in vivo studies. It is reasonable to expect lesser tissue destruction and better regeneration of periodontal tissues if it is used as a root conditioner during periodontal regeneration procedures.

A comparative study of dental pulp response to several pulpotomy agents

To examine the in vivo response of dental pulps in dogs to three pulp-capping agents: calcium hydroxide (CH), mineral trioxide aggregate (MTA) and a new endodontic calcium enriched mixture (CEM) cement. Thirty-six second and third premolar teeth in six beagle dogs were randomly assigned to three experimental groups; CH, MTA or CEM cement. Following isolation and exposure, pulp tissues were removed with a fissure bur and haemostasis achieved. The pulps were dressed with appropriate materials, and the access cavity restored with amalgam. Histological analysis was performed 8 weeks after treatment; the samples were assessed by an independent observer for calcified bridge formation, pulp vitality and pulp inflammation. The data were analysed by Kruskal-Wallis, Mann-Whitney and one-way anova tests. The number of root canals that showed calcified bridge formation, pulp vitality and lack of inflammation was significantly higher for teeth capped with either MTA or CEM cement in comparison with CH (P < 0.05). No significant difference was found between the CEM cement and MTA in terms of calcified bridge formation, pulp vitality and lack of inflammation (P > 0.05). Mineral trioxide aggregate and CEM cement were associated with a similar favourable biological response to pulpotomy treatment and demonstrated a more effective induction of dentinal bridge formation compared to CH.

Three Minimally Invasive Procedures for Removing Lesions in the Maxillary Sinus

We describe here 3 minimally invasive procedures for removing lesions from the maxillary sinus using an ultrathin endoscope, microscope, and otoscope.Preoperatively, a lesion in the maxillary sinus was identified by radiographic examination. Then the access hole position and advance direction of the endoscope and forceps were planned. Under local anesthesia, a small incision on the buccal mucosa was made in the planned position. The anterior bony wall of the sinus was exposed subperiosteally, and a small access hole for the insertion of an endoscope was made in the planned position and angled with a fissure bur. After identification of the lesion endoscopically, microscopically, or otoscopically, a forceps was inserted into the sinus cavity through the hole, and the lesion was seized and withdrawn from the sinus.The surgical procedures are suggested to be reliable, easy, and minimally invasive that provide a limited incision and bone removal and respect the integrity of the sinus.

Adhesion of Two Bonding Systems to Air-Abraded or Bur-Abraded Human Enamel Surfaces

The purpose of this in vitro study was to evaluate whether mechanical alteration of the enamel surfaces with air abrasion and bur abrasion techniques could enhance the bonding performance of a three step and a self etching adhesive resin systems to enamel. 126 extracted lower human incisor teeth were used. The teeth were divided into three groups including 40 teeth each. First group; teeth were used as control and no preparation was made on enamel surfaces, 2(nd) group; outer enamel surfaces were air abraded, 3(rd) group; outer enamel surfaces were abraded mechanically with a diamond fissure bur. Cylinder composite resin blocks were bonded to the buccal enamel surfaces with two bonding systems (20 specimens in each group). Bond strengths to enamel surfaces were measured at a cross-head speed of 1 mm/min. The data were analyzed by ANOVA and Duncan Tests. To examine interface composite resin/enamel surfaces at scanning electron microscopy, remaining 6 teeth were used. Fracture analysis was performed using an optical stereomicroscope. Bond strengths values of Solid Bond were significantly higher than bond strengths of Clearfil SE Bond for all types of enamel (P<.05). Shear bond strength values obtained with Solid Bond (three step system) to three types of enamel surfaces [air-abraded (30.25+/-7.00 MPa), bur-abraded (29.07+/-3.53 MPa), control (31.74+/-7.35 MPa)] were close to each other (P>.05). The macroscopic mode of failures for bonding systems, SB and SE Bond appeared to be adhesive and cohesive in nature. In order to get better bond strength values with self etching systems, it is advisable to prepare enamel surfaces with bur or air abrasion, but it enamel preparation is not necessary for three step systems.

Régénération tissulaire guidée en chirurgie endodontique

Endodontic surgery has for aim to treat bone lesions due to dental-canal infections. The authors investigated the success rate of guided-tissue regeneration (GTR) in endodontic surgery for large periapical lesions. Both bone defects with eroded lingual/palatal and buccal cortex (two-wall defect: transosseous) and lesions with noneroded lingual/palatal cortex (four-wall defect) were assessed. All lesions had a diameter of least 10mm. A total of 73 teeth in 55 patients were included according to specific selection criteria. Full mucoperiosteal tissue flap were used. A straight fissure bur in a hand-piece was positioned apically and 2.5 to 3mm of the root-end were shaved away. Root-end cavities, 2.5 to 3mm deep, were prepared with ultrasonic tips. Root-ends were sealed using Super EBA. The choice of using or not GTR associated with deproteinized bovine bone for each patient wax made by a computer-generated randomized table. For cases allocated to the GTR group, the defect was filled with anorganic bovine-bone mineral and then covered with a resorbable collagen membrane. The outcome was assessed by clinical and radiographic evaluation at one-year follow-up. Sixty-nine teeth were evaluated at one year follow-up. Twenty-six cases were transosseous lesions. At the one-year follow-up, 56 teeth had successfully healed (81.2%), healing was uncertain for 10 teeth and three were classified as failure. The cases classified as uncertain healing were scheduled for another follow-up three years later. According to published data, GTR as a complement of periapical surgery is not necessary for four-wall defects. However, it may be an indication for transosseous lesions.

The effectiveness of a new diamond and carbide fissure burs in cutting amalgam and composite materials

Background: Frequently, new types of burs are developed. The purpose of this study was to evaluate the cutting rates of a new diamond and carbide fissure bures on amalgam and composite materials. Materials and Methods: The cutting study was performed on composite and amalgam an specimens the specimens were divided into groups and subgroups according to the types of bur and material of the specimens: Group I subgroup 1, composite specimens (10 diamond fissure burs), Subgroup 2, amalgam specimens (10 diamond fissure burs), Group II subgroup 1, composite specimens (10 carbide fissure burs), Subgroup 2, amalgam specimens (10 carbide fissure burs). Ten cuts were performed with each bar and a total of 400 cutting rates or CRs (mm/sec) were recorded. The CRs were statistically analyzed using analysis of variance test, least significant difference test and student t-test. Results: There was no significant difference (P< 0.5) between CRs of group I for the 10 cuts, while a significant difference (P < 0.5) began to appear between CRs of group II subgroup 1 after cut 7 and in subgroup 2 after cut 8 Conclusion: Both diamond and carbide fissure burs are effective in cutting amalgam and composite materials, but still carbide fissure bure dulls readily.

Surface area improvement with grooves and boxes in mandibular molar crown preparations

Axial-wall inclination has been shown to affect the stability of a cemented restoration in function, resulting in early restoration failure. The purpose of this study was to evaluate surface area improvement with the use of supplemental grooves in tooth preparations for complete crowns. The surface area preparation improvement in combinations of unfavorable/marginal height and axial-wall inclinations was quantified. A right regular pyramid was used to simulate a single mandibular molar tooth preparation with known axial-wall inclinations and vertical heights. Various combinations of these 2 variables allowed the calculation of surface areas with a formula for the area of a pyramid, cones, and right triangles through geometric/trigonometric manipulations. The pyramidal model system had a 9-mm square base with marginal and unfavorable vertical heights, 3 or 4 mm, and axial-wall inclination angles from 2 to 25 degrees. Conical-shaped grooves of varying lengths and widths, depending on height and axial-wall inclinations, were introduced with a tapered fissure bur. The percentage of surface area gained or lost through the supplementation with tapered grooves and boxes served as the dependent variables, alpha-factors (1) through (5). Significant area gains were demonstrated in all alpha-level comparisons. The greatest change was found in the 4-mm height grouping, as a positive 35.2% gain in the 25-degree level with 4 grooves. Axial-wall groove and box supplementation were shown to improve the surface areas of simulated mandibular molar preparations with unfavorable axial-wall inclination and vertical height levels.

Accuracy of Using the Antilingula as a Sole Determinant of Vertical Ramus Osteotomy Position

The antilingula is an important landmark in mandibular ramus surgery. Its relationship to the lingula provides useful clinical information as to the position of the mandibular foramen and inferior alveolar nerve. The purpose of this study was to determine the reliability of using the antilingula as a guide to osteotomy placement for intraoral vertical ramus osteotomies. Eighteen cadaver mandibles were harvested and the antilingula was identified on each hemimandible by palpating the most prominent bulge on the lateral aspect of the mandible. In addition, the lingula (the entrance of the mandibular neurovascular bundle into the medial aspect of the ascending ramus of the mandible) was identified. A 1 mm fissure bur was used to drill a hole perpendicular to bone, from the deepest aspect of the concavity at the center of the lingula. The drill perforated both the medial and lateral cortices of the mandible. The distance from the antilingula to lingula was measured and recorded in both the anterior-posterior and the superior-inferior planes. There was complete concordance of the position of the lingula and antilingula in the anterior-posterior dimension in 11.1% of the specimens. In 33% of the specimens, the lingula was found anterior to the antilingula and in 45.6% the lingula was found posterior to the antilingula. There was complete concordance of the lingula and antilingula in the superior-inferior dimension in 2.8% of specimens. The lingula was found superior to the antilingula in 47.2% of the specimens and inferior to the antilingula in 50% of samples. In most instances, the position of the lingula was posterior-inferior relative to the position of the antilingula. At a measurement of 5 mm posterior to the antilingula (at the level of the antilingula), there was no risk of damaging the neurovascular bundle in this cadaveric study.

Etiology of Lingual Nerve Injuries in the Third Molar Region: A Cadaver and Histologic Study

It has been suggested that different etiologies of lingual nerve damage in the third molar area will produce a different clinical and histologic appearance in the nerve. If the clinical and histologic pictures were different, it could result in different treatments being recommended. Eight preserved cadavers (16 lingual nerves) were used for this study. As far as possible, the nerves were left in situ and damaged in a way that could be envisaged during third molar surgery. In each case, the damaged sections of nerve were photographed, resected, embedded in paraffin wax, sectioned in 5 mum sections, stained with hematoxylin-eosin, and examined histologically. The scalpel clinically produced a clean wound with sharply defined edges; this was confirmed histologically with minimal disruption to the fascicles. The 702 fissure bur produced a ragged stretch-type injury clinically, and histologically this was confirmed with an irregular-edged border to the lesion and stretching and internal damage to the fascicles immediately adjacent to the wound. The crush injury clinically caused considerable apparent damage to the nerve, which was confirmed histologically with crushing and disruption of the fascicles and reduction to approximately 25% of their preinjury thickness. The stretch injury clinically showed no damage, but histologically showed irregular internal disruption of the fascicles over the whole area subject to stretching movements. It does appear that different modalities in nerve injury produce a different type of injury both clinically and histologically. This information has implications for both natural clinical recovery and the indications for surgical intervention. Clinical recovery may occur best with close approximation of a sharp scalpel-type wound or excision of a crushed area of nerve with reapproximation of the nerve endings, but a ragged wound caused by a fissure bur may require excision back to healthy nerve with subsequent reapproximation, whereas with the stretching injury it may be difficult to ascertain the edges and limits of the wound, and difficult to repair, and it may be most appropriate to rely on a natural healing process for the best results.

Bacterial leakage of mineral trioxide aggregates and portland cement.

The purpose of this study was to compare the ability of ProRoot mineral trioxide aggregate (PMTA) and Root mineral trioxide aggregate (RMTA) as root-end filling materials, and Portland cement (PC) to prevent bacterial leakage through filled root end cavities. Fifty-one extracted human single rooted teeth were cleaned and shaped using a step back technique. The root-ends were resected and a 4 mm deep root-end preparation was made with fissure bur. The teeth were randomly divided into three experimental groups (n=15) and a further six teeth served as controls. Three root-end cavities were filled with gutta-percha without a root canal sealer (positive control) and three remaining were filled with sticky wax, covered with two layers of nail polish (negative control). Root-end cavities in each experimental group were filled with PMTA, RMTA or PC. After attaching the teeth to plastic caps of 9 ml vials, the teeth and the caps were sterilized using Gamma ray. Then the caps with teeth were placed on the vials containing Phenol Red Lactose broth. A tenth of microliter of Tripticase Soy broth containing Staphylococcus Epidermidis (SE) was placed into the root canals of the teeth. Every 48 hours inoculation of 0.1 ml of the SE broth culture into each root canal was performed. All positive controls leaked within 3 days, none of the negative controls leaked. Bacterial leakage occurred in 33% of samples in the PMTA group and in 40% of samples in RMTA and PC groups. The results indicated no statistical difference between three test materials after 35 days. It was concluded that PMTA, RMTA and PC demonstrated a similar ability to seal root end cavities.

Histomorphology on Healing of the Chitosan Membrane and β-TCP on Dental Implant Dehiscence Defects in Dogs

Dehiscence bone defects, frequently observed on dental implants placed in periodontitis-affected alveolar bone or extraction sockets were treated with β-tricalcium phosphate (β –TCP) and chitosan membrane for guided bone regeneration, and the new bone formation on the treated sites were studied. Beagle dogs were used for the experiment. First to fourth mandibular premolars were extracted, and the post extraction alveolar bone surface was planed. After 8 weeks of healing, 3 by 4mm dehiscence defects were created using straight fissure burs. Total of 16 oxidized titanium surface implants were placed on the bone defects of the subjects, two on each side. Control sites were treated with implants only. Experimental Group 1 sites were treated with implants and chitosan membrane. Experimental Group 2 sites were treated with implants, β-TCP and chitosan membrane. Experimental Group 3 sites were treated with implants, β-TCP, autogenous bone and chitosan membrane. The animals were sacrificed 12 weeks after implant placement, and the specimens from the treated sites were histologically studied with following results. Limited amount of new bone formation was observed in control group with unexposed membrane. Slightly greater amount of bone formation was observed on sites treated with β-TCP+membrane or autogenous bone+ β-TCP+membrane compared to control group. Remnants of chitosan membrane and β-TCP encapsulated with connective tissue were observed during experimental periods. These results suggest that further studies are needed on membrane rigidity and infection control for space maintenance underneath the membrane and bone substitutes in the treatment of dehiscence defects.

Functional Sensory Return Following Trigeminal (V3) Nerve Repair

(Donoff RB; Kaban LB; Dodson TB)

A New Method to Harvest Ramus Bone Using the Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser

Autogenous, monocortical block grafts are used extensively in alveolar ridge augmentation prior to implant placement. The main indication is either a defect or atrophy in the anteroposterior or buccolingual dimension, which will prevent implant placement. Donor sites available for implant reconstruction have been described in the literature. Extraoral donor sites such as the ilium, 1 Keller E.E. vanRoekel N.B. Desjardins R.P. et al. Prosthetic-surgical reconstruction of the severely resorbed maxilla with iliac bone grafting and tissue-integrated prostheses. Int J Oral Maxillofac Implants. 1987; 2: 155 PubMed Google Scholar calvaria, 2 Cain J.R. Mitchell D.L. Markowitz N.R. et al. Prosthodontic restoration with dental implants and an intraoral cranial bone onlay graft A case report. Int J Oral Maxillofac Implants. 1993; 8: 98 PubMed Google Scholar , 3 Donovan M.G. Dickerson N.C. Hanson L.J. et al. Maxillary and mandibular reconstruction using calvarial bone grafts and Branemark implants A preliminary report. J Oral Maxillofac Surg. 1994; 52: 588 Abstract Full Text PDF PubMed Scopus (103) Google Scholar clavicle, 4 Listrom R.D. Symington J.M. Osseointegrated dental implants in conjunction with bone grafts. Int J Oral Maxillofac Implants. 1988; 17: 116 Abstract Full Text PDF Scopus (108) Google Scholar and scapula 5 Buchbinder D. Urken M.L. Vickery C. et al. Functional mandibular reconstruction of patients with oral cancer. Oral Surg Oral Med Oral Pathol. 1989; 68: 499 Abstract Full Text PDF PubMed Scopus (53) Google Scholar require hospitalization and are not without potential morbidity. The tibia is not recommended, as only cancellous bone is available in satisfactory amounts for grafting procedures. 6 Lee C.Y.S.L. An in-office technique for harvesting tibial bone Outcomes in 8 patients. Oral Implantol. 2003; 29: 181 Crossref Google Scholar Intraoral ramus grafts from the mandible have also been used and should be the primary harvest site when possible. Advantages are reduced in-office operative and anesthesia time, low morbidity, and ease of surgical access, which can be accomplished under local anesthesia or intravenous sedation. For the young patient who has not had the mandibular third molars removed, harvesting of ramus grafts with simultaneous removal of the third molar should also be considered, as only one surgical procedure is required. The armamentarium to harvest bone from the ramus of the mandible is usually a fissure bur in a high-speed handpiece or oscillating saw. The purpose of this article is to introduce a new alternative method to harvest ramus bone from the mandible using the latest generation laser, the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser.

Microleakage around Glass-Ceramic Insert Restorations Luted with a High-Viscous or Flowable Composite

The purpose of this study was to evaluate microleakage around Class V resin restorations restored with glass-ceramic inserts luted with a high-viscous composite resin or a flowable composite resin. Twenty extracted human premolars (patient age range 12-18 yr) were randomly assigned to four groups. Class V preparations in two groups were filled using a glass-ceramic insert (Megafiller Standardformen, Hager Werken GmbH, Duisburg, Germany) luted with either a hybrid, high-viscous composite (Tetric, Ivoclar Vivadent, Schaan, Liechtenstein) and a bonding agent (Excite, Ivoclar Vivadent) or a flowable composite (Crystal-Essence, Confi-Dental, Louisville, CO, USA) and a bonding agent (Confi-Quick, Confi-Dental). Two groups without inserts served as controls and were bulk filled with either a hybrid, high-viscous composite (Tetric) or a flowable composite (Crystal-Essence). The preparations were made with a no. 330 tungsten carbide fissure bur (Komet, Lemgo, Germany) in a water-cooled, high-speed handpiece with a mesiodistal width of 3 mm, an occlusogingival height of 3 mm, and a depth of 2 mm. All margins had butt joints. The teeth were thermocycled for 24 hours in water baths held at 5 degrees C and 55 degrees C, and the specimens were prepared and examined for microleakage using basic fuchsin as a marker. Relative leakage was recorded according to the extent of dye penetration on a scale of 0 to 4, with 0 indicating no dye penetration and 4 indicating that dye penetration had progressed as far as the cavity floor. The results were analyzed using the Kruskal-Wallis test (nonparametric analysis of variance) and Dunn's multiple comparisons test (p < .05). There was no significant difference in microleakage around inserts luted with a high-viscous composite occlusally (p = .7563) or gingivally (p = .6187) and around cavities bulk filled with the high-viscous composite. There was a significant difference in microleakage around inserts luted with a flowable composite both occlusally (p = .0345) and gingivally (p = .0285) and around cavities bulk filled with the flowable composite. Inserts luted with the flowable composite showed significantly less microleakage than those cemented with the high-viscous material only at the gingival margins (p = .0345). Comparisons of microleakage around the high-viscous and flowable composites showed no significant difference in microleakage at either the occlusal or gingival margins (Dunn's multiple comparisons test p > .5 in all cases). In Class V preparations of the size cut in the present study, ceramic inserts are shown to be of value in reducing microleakage when compared with bulk filling with flowable composites. Microleakage was not significantly improved by using a ceramic insert with a viscous composite compared with the viscous composite alone.

The Effects of Water and Acetone-based Dentin Adhesives on Apical Microleakage

In this study, the aim was to assess the in vitro apical microleakage of a resin-based sealer used with two different adhesives. Thirty nine freshly extracted maxillary incisors were used. The teeth were decoronated at the cemento-enamel junction with a water-cooled fissure bur. Chemo-mechanical debridement of the root canals was accomplished with the step-back technique. The smear layer was removed by 19% ethylenediamine tetra acetic acid (EDTA). The roots were then divided into three experimental groups of thirteen teeth in each. Specimens in group 1 were filled with gutta-percha, AH Plus sealer, and water-based adhesive system (Syntac Single Component). Group 2 specimens were filled with gutta-percha, AH Plus sealer, and acetone-based dentin adhesive (Prime & Bond NT ). Specimens of group 3 were filled with only gutta-percha and AH Plus sealer (no adhesive was applied). The teeth were immersed into 2% methylene blue solution. Apical sealing qualities were assessed by measuring the linear dye penetration with a stereomicroscope. Dentin tubule penetration was observed under scanning electron microscopy (SEM). Results showed no statistically significant difference between the materials used, however, the leakage in group 2 was less than group 1 and 3.

Effect of enamel matrix proteins (Emdogain') on healing after re-implantation of "periodontally compromised" roots. An experimental study in the dog.

The present experiment was performed to assess whether Emdogain applied on the root surface of extracted teeth or teeth previously exposed to root planning can protect the tooth from ankylosis following re-implantation. The experiment included two groups of dogs, including five animals each. The root canals of all mandibular third premolars (3 P 3) were reamed and filled with gutta-percha. A crestal incision was placed from the area of the second to the fourth premolar. Buccal and lingual full thickness flaps were elevated. With the use of a fissure bur, the crown and furcation area of 3 P 3 were severed in an apico-coronal cut. The distal and mesial tooth segments were luxated with an elevator and extracted with forceps. Group A: The mesial and distal segments of 3 P 3 were air dried on a glass surface for 60 min. The roots from the right side were conditioned and exposed to Emdogain application. The roots from the left side received the same treatment with the exception of Emdogain application. The mesial and distal tooth segments were re-implanted and the crown portions were severed with a horizontal cut and removed. The buccal and lingual flaps were mobilized and sutured to obtain complete coverage of the submerged roots. Group B: A notch was prepared in each root, 4-5 mm apical of the cemento-enamel junction. The area of the root that was located coronal to the notch was scaled and planned. The roots in the right side of the mandible were treated with Emdogain, while the roots in the left side served as controls. After 6 months of healing, the dogs were killed and blocks containing one root with surrounding tissues were harvested, and prepared for histological examination, which also included morphometric assessments. Thus, the proportions of the roots that exhibited signs of (i) replacement (ii) inflammatory and (iii) surface resorption were calculated. It was demonstrated that healing of a re-implanted root that had been extracted and deprived of vital cementoblasts was characterized by processes that included root resorption, ankylosis and new attachment formation. It was also demonstrated that Emdogain treatment, i.e. conditioning with EDTA and placement of enamel matrix proteins on the detached root surface, failed to interfere with the healing process.

A pilot study of measurement of the frequency of sounds emitted by high-speed dental air turbines.

Since the development and use of the high-speed dental air turbine some 45 years ago, concern has been expressed in the literature about a possible cause and effect relationship between use of the drill and hearing loss in dentists. The hearing threshold in humans varies with the frequency of sound. It is well known that dentists experience gradual hearing loss during their working life. The aim of this study was to measure the frequency of sounds emitted by high-speed dental air turbines under different working conditions. Five high-speed dental air turbines were used (2 x Trend TC-80 BC W&H Dentalwerk, Austria, 2 x Black Pearl Eco Bien-air, Switzerland, 1 x Trend TC-80 BC W&H Dentalwerk, Austria. Each turbine was tested under 8 different working conditions: under free working conditions the turbines were tested without burs, with fissure burs, with flare burs, with round burs and with inverted cone burs; under operation they were tested with fissure burs by application to a 3 x 3 x 10 mm amalgam block surface, a 3 x 3 x 10 mm composite block surface, and the occlusal surface of an extracted molar tooth. Forty sound recordings were made in total using a computer with a microphone (Shure 16 LC) located 30 cm away from the samples, at 10-s intervals using a mixer. Frequency analysis was done by a Cool Edit Pro 1.2 computer program. Data were analyzed by multi-variate analysis with the S.P.S.S 9.05 software program. The average measurement was 6860 Hz. According to the statistical analysis there was no significant difference in the frequencies recorded under different working conditions. There was also no significant difference among the different high-speed dental air turbines at alpha = 0,05, P > alpha /2 levels. These results indicate that under any working conditions, high-speed dental air turbines emit frequencies which can cause hearing loss.

Cutting efficiency of air-turbine burs on cast titanium and dental casting alloys

Objective: The purpose of this study was to investigate the cutting efficiency of air-turbine burs on cast free-machining titanium alloy (DT2F) and to compare the results with those for cast commercially pure (CP) Ti, Ti–6Al–4V alloy, and dental casting alloys. Methods: The cast metal (DT2F, CP Ti, Ti–6Al–4V, Type IV gold alloy and Co–Cr alloy) specimens were cut with air-turbine burs (carbide burs and diamond points) at air pressures of 138 or 207 kPa and a cutting force of 0.784 N. The cutting efficiency of each bur was evaluated as volume loss calculated from the weight loss cut for 5 s and the density of each metal. The bulk microhardness was measured to correlate the machinability and the hardness of each metal. Results: The amounts of DT2F cut with the carbide burs were significantly ( p<0.05) greater than for the other titanium specimens at either 138 or 207 kPa. The diamond points exhibited similar machining efficiency among all metals except for Type IV gold alloy. The increase in the volume loss of Co–Cr alloy (Vitallium) cut with the diamond points showed a negative value (−29%) with an increase in air pressure from 138 to 207 kPa. There was a negative correlation between the amounts of metal removed (volume loss) and the hardness ( r 2=0.689) when the carbide burs were used. Significance: The results of this study indicated that a free-machining titanium alloy (DT2F) exhibited better machinability compared to CP Ti and Ti–6Al–4V alloy when using carbide fissure burs. When machining cast CP Ti and its alloys, carbide fissure burs possessed a greater machining efficiency than the diamond points and are recommended for titanium dental prostheses.

Enameloplasty effects on microleakage of pit and fissure sealants under load: an in vitro study.

Enameloplasty has been implicated in the successful application of pit and fissure sealants. The present study aimed to evaluate the effect of enameloplasty technique on microleakage of sealants when occlusal force was applied on the teeth. The study also allowed a direct comparison of the effectiveness of enameloplasty, when two different burs were used. Six groups of ten human extracted wisdom teeth were tested. Group A: no load, conventional (no enameloplasty--control); Group B: no load, enameloplasty 1/2 round bur (Brasseler USA); Group C: no load, enameloplasty diamond fissure bur REF/UP 791 (Ultradent); Group D: load 500 N, conventional, Group E: load 500 N, 1/2 round bur; Group F: load 500 N, diamond fissure bur. Specimens were thermocycled for 500 cycles at 5 degrees C and 55 degrees C with a dwell time of 30 seconds after load application. Microleakage was scored as distance of dye penetration with 0 = no microleakage and 3 = microleakage to underling fissure. The Kruskal-Wallis One Way Anova and Mann-Whitney U test showed group D having the greatest degree of microleakage statistically significant (p < 0.05) comparing with other groups. Sealants prepared with the conventional technique (A, D) had statistically significant differences in microleakage with those prepared with enameloplasty (B, C, E, F) (p = 0.01). Enameloplasty in groups with no load (B, C) did reduce microleakage, but not significantly (p = 0.3). However, loaded teeth with enameloplasty appeared to perform superior, as compared to those without (p = 0.005). Regarding the effect of load, teeth without load (Groups A, B, C) were found to have significantly less microleakage than teeth where mechanical force had been applied (Groups D, E, F), (p = 0.01). Microleakage in Group A (conventional technique without load) was significantly less than microleakage in Group D (conventional technique with load), (p = 0.04). However, load did not seem to influence microleakage when enameloplasty had been performed. This finding was true for both round bur enameloplasty (p = 0.29), and fissure bur enameloplasty (p = 0.26). There was no statistically significant difference between Groups B, E (round bur) and C, F (fissure bur) (p > 0.05), or between Groups B and C (p > 0.05) and between Groups E and F (p > 0.05). The results of the study indicated that enameloplasty reduced microleakage of pit and fissure sealants, especially when load was applied to teeth, irrespective of what bur was used to enlarge the fissure, as there was no statistical significant differences between the round and fissured diamond burs. The application of occlusal force to the tooth produces significantly more microleakage, unless enameloplasty is performed.