Quintessence International, 08/2007

This article describes a technique used to treat superficial white spot lesions by a mini-mally invasive approach. The proposed technique is based on reactivation of enamel by elimination of its hypermineralized external layer through microabrasion, followed by daily home application of casein phosphopeptide-amorphous calcium phosphate complexes (CCP-ACP). The technique may allow elimination of white spot lesions without involving restorative procedures. Microabrasion followed by long-term daily home application of CCP-ACP may be considered an interesting alternative to the restorative approach for treatment of white spot lesions. Keywords: CCP-ACP, microabrasion, minimally invasive treatment, white spot lesions

Objectives: To evaluate and compare shear bond strength of 3 self-etching bonding agents to enamel and dentin when the bonding agent is light cured before the application of resin composite or co-cured together with the resin composite. Method and Materials: One hundred twenty extracted teeth were wet ground to create a flat bonding area on enamel and dentin. Three bonding agents (Adper Prompt-L-Pop, Clearfil SE Bond, and Xeno III) were applied to either dentin or enamel according to the manufacturers' directions. In half of the specimens, bonding agents were light cured immediately after their application (Group PRC). The other half were not light cured until resin composite application (Group COC). Resin composite was placed into a Teflon tube and light cured over the adhesive. Specimens were stored in deionized water for 24 hours at room temperature before being loaded in shear until failure with an Instron testing machine. Shear bond strength (in megapascals) was analyzed with 2-factor ANOVA, separate single-factor ANOVA models for cure and material, and Tukey's Honestly Significant Differences multiple comparison procedure. All testing was performed at the 5% significance level (n=10). Results: Light-curing the adhesive separately produced significantly higher bond strengths to dentin (P < .001) than did the co-cure method. Group PRC did not produce significantly different bond strengths to enamel (P = .420). Conclusions: Pre-curing of self-etching adhesives before curing of the resin composite produces greater bond strength to dentin. The curing technique has no significant effect on enamel bond strength of self-etching adhesives. Keywords: bonding agents, adhesives, resin bonding

Objective: To evaluate the long-term performance of machined screw implants placed in partially edentulous patients. Method and Materials: Eighty-six patients received a total of 214 machined implants (3i Implant Innovations). Seventy-six patients received 112 crowns and fixed partial dentures. The implants were placed in both the maxilla and the mandible. Using standardized radiographs, the peri-implant bone level was evaluated at the time of delivery of the final restorations and at up to 8 follow-up examinations. Results: Nine implants failed before and 6 implants during functional loading. Further, 30 implants were classified as biologically unsuccessful. The estimated survival rate of the implants was 93% after 84 months (confidence interval 88% to 97%). The estimated success rate was 83.3% after 84 months (confidence interval 76.4% to 90.2%). Conclusion: Machined 3i implants can be used for the replacement of missing teeth in partially edentulous patients. Keywords: dental implants, fixed partial dentures, partial edentulism, survival rate, success rate

Patients with a compromised periodontal condition and a breakdown in occlusal support may require periodontal and prosthodontic treatment in conjunction with orthodontic treatment. Orthodontic treatment of these patients is possible and would involve removal of inflammation and occlusal interference and provision of an environment for proper restorative rehabilitation. A different approach to the orthodontic treatment of these patients is required in terms of treatment manner, stabilizing anchorage systems, force systems, retention, and plaque control during treatment. This report describes the case of a 49-year-old woman with severely compromised periodontal tissues, multiple missing teeth, and malocclusion. Highly esthetic and functional results were achieved by treatment with orthodontics as well as periodontal therapy, including guided tissue regeneration and implant restoration with sinus lift. Keywords: advanced periodontal disease, implant restoration, interdisciplinary treatment, orthodontic treatment, pathologic tooth migration, periodontal treatment, prosthodontic rehabilitation, regenerative therapy

Objective: To evaluate the speed (efficiency) and effectiveness of 3 different fiber post removal systems. Method and Materials: Fiber posts (D.T. Light-Post no. 1 [Bisco Dental] and ParaPost FiberLux no. 5 [Coltène/Whaledent]) were cemented into 60 single-rooted teeth after endodontic therapy and post space preparation were completed. Three methods of fiber post removal were evaluated-D.T. Light-Post removal kit, the Kodex twist/Tenax ParaPost fiber post removal drill kit, and a combination of diamond bur/Peeso reamer. Results: The efficiency to remove either fiber post was not significantly different, nor was efficiency of any of the 3 post removal systems significantly different. For effectiveness, no difference was observed between post types, but effectiveness was higher with the diamond bur/Peeso reamer compared with the Kodex twist/Tenax ParaPost drills, which in turn was more effective than the D.T. Light-Post removal kit. Conclusions: Fiber posts are efficiently removed by all 3 methods, but effectiveness of removal is higher using the diamond bur/Peeso reamer. Keywords: fiber posts, post and core technique, post removal

Objective: To determine if surface disinfectants cause a change in the shade perception of a standard Classic Vitapan shade guide. Method and Materials: Consistency in shade selection for dental restorations involves many factors, and one of the most important is the shade tabs used in the selection process. Ten shade tabs each of shades B2, D2, C1, and A3.5 were selected from the Classic Vitapan shade guide (Vident). All tabs were measured with the EasyShade shade device (Vident) at baseline. Three tabs of each shade were set aside as controls. The other 7 tabs of each shade were treated with the surface disinfectant Cavicide (Metrex Research) for 480 cycles to simulate a year's usage. After each 480 cycles, all the tabs were again measured with the EasyShade. This process was repeated to simulate 2 and 3 years of use. Results: The data were analyzed to calculate the delta E 2000 for any change. A statistically significant increase was observed in the value (L*) and chroma (C*) after 2 and 3 years of simulated treatments. These changes were not perceptible to the clinician. Conclusions: The authors suggest that 1 standard shade guide be set aside to compare against those in clinical use to determine when they should be replaced. Keywords: delta E changes in shade tabs, shade guide, shade tab changes, surface disinfectants

Eosinophilic ulcer of the oral mucosa is a benign, rare, self-limiting, and generally asymptomatic lesion that shows spontaneous regression. Its etiopathogenesis is still uncertain, but trauma seems to play a fundamental role in the occurrence of this tumor. Clinically, this lesion manifests as an isolated ulcer preferentially located on the tongue, showing a raised and indurated border in addition to a white or yellowish bed. Microscopically, eosinophilic ulcer is characterized by an inflammatory infiltrate rich in leukocytes. Since these lesions show spontaneous cure, treatment becomes unnecessary, but in certain cases, cure is obtained by excision of the ulcer during biopsy. In these cases, the differential diagnosis with squamous cell carcinoma is made. A case of very small eosinophilic ulcer of the oral mucosa located on the lateral border of the tongue is presented. Keywords: eosinophilic granuloma, eosinophilic ulcer, oral mucosa, tongue, trauma, traumatic ulcer

Objective: To study the effects of positioning individuals with cerebral palsy (CP) on a dental chair according to the neurodevelopmental treatment (NDT) approach, to establish the best position to perform dental care in the safest and most efficient manner in such individuals. Method and Materials: A group of 158 noninstitutionalized patients (78 males and 80 females) with CP (mean age 10.5 [SD ± 4.6]) were enrolled in the study. The behavior management techniques used were tell-show-do, voice control, assistive stabilization, oral premedication, a combination of techniques, and general anesthesia. Results: The tell-show-do and voice control techniques were effective for only 36 (22.8%) of the patients who were collaborators: 3 presenting spastic diplegic, 23 presenting spastic hemiplegic, 4 presenting spastic double hemiplegic, and 6 presenting ataxic CP. The totality of patients with spastic quadriplegic CP, dystonic CP with athetosis, and mixed CP required all the combined forms of assistive stabilization and postural maintenance. The majority of the individuals with spastic diplegic CP required head and upper member stabilization and a mouth prop. Among the dental care treatments performed, preventive care (dental prophylaxis, sealants, and fluoride application) was performed on 78 (50.0%) patients, restorative dentistry on 40 (25.6%), and oral surgery on 38 (24.4%). Conclusion: Present data suggest that the use of assistive stabilization was effective and permitted the dental care of individuals with CP at the outpatient clinic level, while reducing the number of patients referred for general anesthesia and ensuring better quality of life for this patient population regarding oral health. Keywords: assistive stabilization, cerebral palsy, dental care, neurodevelopmental treatment approach, outpatient clinic

Antibiotics are used for prophylactic and therapeutic purposes. Since bacterial resistances constantly change the existing conditions, the patient's therapy needs to be monitored periodically and adjusted to the changed conditions. Clinicians should be very careful about prescribing antibiotics for prophylactic purposes. But with regard to risk patients - especially when there is a risk of endocarditis - antibiotic prophylaxis is essential. Antibiotic therapy is absolutely necessary as a supporting treatment for primary surgery if the patient has acute osteomyelitis, transmitted abscesses, or multiple space abscesses. It might also become necessary to refer the patient to an appropriately equipped center or clinic. Keywords: antibiotic prophylaxis, antibiotics, odontogenous infection, oral surgery

Idiopathic or hereditary gingival fibromatosis is a benign oral disorder characterized by enlargement of the oral gingival tissues. This article describes a case of a female child who exhibited a generalized gingival overgrowth in both arches at birth. Other causes of gingival overgrowth and the clinical, radiographic, and histopathologic characteristics are discussed. Treatment consisted of surgical removal of the hyperplastic fibrous tissue in a series of gingivectomies. Medical history, clinical examination, and histopathologic and genetic findings were essential to rule out other systemic abnormalities. This unusual case of nonsyndromic idiopathic gingival fibromatosis was followed for 5 years, and no recurrence was seen. Keywords: gingival overgrowth, idiopathic gingival fibromatosis, surgical treatment

Objectives: To determine the prevalence of oral leukoplakia and erythroplakia in a group of Thai patients and to study the clinical and pathologic features of these 2 lesions. Method and Materials: Cases having provisional diagnoses of leukoplakia and erythroplakia between 1973 and 2004 were retrieved from the files of the Department of Oral Pathology, Faculty of Dentistry, Mahidol University. Clinical and pathologic features were reviewed and analyzed. Results: Of 7,177 biopsy specimens, 123 cases (1.7%) of leukoplakia and 9 cases (0.13%) of erythroplakia were found. There was no significant gender predilection in leukoplakia (male:female = 1.2:1). The peak of age-frequency distribution of leukoplakia was in the fourth decade among men and fifth decade among women. The most common site of leukoplakia was buccal mucosa (28.5%), followed by alveolar mucosa (18.7%) and tongue (16.3%). Microscopic study of leukoplakia revealed hyperkeratosis with or without acanthosis in 60.9% of cases, epithelial dysplasia in 10.6%, and squamous cell carcinoma in 4.9%. Erythroplakia was found in 6 men and 3 women. It was most frequently seen during the seventh decade of life. The palate was the most common site. Epithelial dysplasia and squamous cell carcinoma were found in 6 patients with erythroplakia (66.7%). Conclusions: Leukoplakia occurred 13 times more frequently than erythroplakia. However, squamous cell carcinoma was more frequently found in erythroplakia cases. Both lesions were found most frequently in elderly individuals and affected men more than women. Keywords: clinicopathologic study, erythroplakia, leukoplakia, Thai

Objective: To determine if 2 commercial mouthrinses, 1 alcohol-based and 1 nonalcohol-based, affect salivary flow and symptoms of dry mouth in nonxerostomic adults. Method and Materials: This observer-blinded, randomized, crossover pilot study involved 20 adults. The primary endpoints of interest were whole salivary flow rates and the perceived mouth dryness VAS scores following 1 week of use. ANOVA was used to determine differences in these endpoints between groups, and ANCOVA was used to control for any variation in baseline flow rates and VAS scores (P < .05). Results: There were no significant differences between groups at baseline. After 1 week of mouthrinse use, ANOVA and ANCOVA of combined data (before and after crossover) revealed no significant differences in either flow rates or VAS scores between groups (P > .05). Conclusion: There were no differences in objective or subjective measures of mouth dryness between alcohol- and nonalcohol-containing mouthrinses after 1 week in nonxerostomic subjects. Keywords: alcohol, dry mouth, mouthrinse, xerostomia

Objective: The Probond metal-ceramic system was proposed as an alternative to conventional metal-ceramic restorations. This study examined the 7-year survival and clinical performance of Probond metal-ceramic crowns. Method and Materials: A total of 200 patients were included in the study. All subjects required single-unit fixed prosthodontics in various areas of the mouth.The patients without any active periodontal or pulpal diseases, having adequate tooth structure and good oral hygiene, were included in the study, while patients with parafunctional habits were excluded. Overall clinical performance over 7 years was determined by using modified USPHS criteria and evaluated with Kaplan-Meier survival analysis. Results: Seven failures were recorded among the 260 crowns placed. In the 4th year, 2 Probond crowns had minimal incisal fractures, and 1 restoration had a cervical fracture in the 2nd year. After 7 years, 2 Probond crowns were replaced with new Probond crowns as a result of fracture or trauma. Two restorations lost their occlusal contact integrity due to marginal ridge fractures. The formation of cracks and fractures as well as caries were significant (P < .05) at the 4- and 7-year recalls. Overall survival rates for marginal integrity, color stability, caries and crack formations, and occlusal integrity were 90.7%, 98.1%, 98.1%, 95.4%, and 99%, respectively, at 7 years. Conclusion: The durability of Probond ceramic crown restorations proved to be successful after 7 years. Keywords: ceramic crown, clinical follow-up, perforated metal framework, Probond

Objectives: This study tested the hypothesis that the size of repair sites on amalgam restorations with mechanical undercuts on the repair surface would affect interfacial strength using a 3-point bending test. Method and Materials: Six groups of 12 rectangular bars each were fabricated from an admix alloy and a spherical alloy. Each specimen was cut into 2 equal-sized end sections, and 1 smaller midsection, which was discarded. A medium-coarse diamond disk was used to roughen and flatten the surface for repair. The 2 end sections were fit back into the original mold. The empty space in the middle was approximately 1, 1.5, and 2 mm, mimicking the size of repair sites to be filled with amalgam. There were 2 groups for each repair size; 1 group had rounded undercuts prepared on the surface for repair with a 1/2 round bur, and the other group received no additional treatment. Condensation was carried out with condensers having a dimension slightly less than the width of the repair defect. After 7-day storage, a 3-point bending test was used to determine the repair strengths of the specimens. Results: The strength values ranged from 33.9 to 75.6 MPa, which is comparable to published data. ANOVA showed that the mean strength values were higher with spherical amalgam (P < .0001), were lower with undercut (P = .0148), and increased as the width of repair site decreased (P < .0001). Conclusion: Reducing the dimension of the repair site improved repair strength, but rounded undercuts reduced the repair strength values slightly. Keywords: admix, amalgam, condensation, defect, flexure strength, repair, spherical

Arteriovenous malformations (AVMs) are an abnormal collection of blood vessels. They are extremely rare congenital or acquired abnormalities in the structure of blood vessels. These malformations have been associated with severe hemorrhage resulting in significant morbidity and mortality. Gingival bleeding seems to be a common symptom of most documented cases of AVM, and radiographs most often appear normal. A 12-year-old girl who was first examined by a general dentist for occasional bleeding associated with the right mandibular teeth was referred to the University of Istanbul, Faculty of Dentistry. During the suturing process to stop the leakage around the mandibular right first molar, uncontrollable hemorrhage began. Magnetic resonance imaging and angiogram revealed the AVM of the right mandibular body. After embolization with an injection of a mixture of cyanoacrylate and lipiodol, the tooth was extracted and initial periodontal therapy performed. The patient has maintained a satisfactory gingival and oral condition since the completion of dental treatment and establishment of oral hygiene. Clinicians should be aware of these lesions and the impact they can have on routine procedures. Proper recognition and therapeutic intervention can help to avoid serious complications and potentially tragic outcomes. Keywords: arteriovenous malformations, dental extractions, periodontal treatment

Objectives: To present data on hemodynamic changes during dental extractions in 5 patients with cardiac sarcoidosis, performed with electrocardiogram, heart rate, and blood pressure monitoring throughout the procedures, and to discuss the problems relating to the disease and dental extraction. Method and Materials: The medical data for 5 patients, including medical records, physician correspondence, and laboratory data before the treatments, were assessed. Seven dental extractions were then performed while monitoring and recording the hemodynamic conditions. Heart rate, blood pressure, rate pressure products, and electrocardiographic findings were analyzed. Finally, posttreatment evaluations of the general and local conditions of the patients were conducted. Results: All dental extractions were performed in nonactive stable periods, with no remarkable hemodynamic changes or complications, while maintaining a stable hemodynamic state throughout the extraction procedure. All patients received a pretreatment supplement of corticosteroid. Wound healing was similar to that in normal patients under antibiotic prophylaxis against infection originating from the dental extraction wound and the original dental lesion. Conclusion: Pretreatment general evaluation of patients with cardiac sarcoidosis should be performed through various examinations and physician consultation, and a stable hemodynamic change during the surgical procedure should be maintained under any hemodynamic monitors. Corticosteroid supplement and antibiotic coverage are also necessary for safe dental extraction and suitable healing. Keywords: antibiotic prophylaxis, cardiac sarcoidosis, corticosteroid, dental extraction, hemodynamic monitoring

Objective: The recently introduced Vector system is recommended to be used in conjunction with a polishing fluid containing hydroxylapatite granules (< 10 µm). The aim of the present study was to assess morphologic alterations of the root surface after ultrasonic treatment with the polishing fluid. Method and Materials: Cementum of 30 freshly extracted human teeth was removed to a level of 4 mm below the cementoenamel junction. Surfaces were root-planed and conditioned with citric acid to remove the smear layer. Teeth were divided into 5 groups, with group 1 as the untreated control. Group 2 was solely treated with the ultrasonic system. In group 3, the ultrasonic system was used in conjunction with the polishing fluid. Group 4 was treated with a medium-hard toothbrush and the polishing fluid. Group 5 was treated only with the toothbrush. Specimens were evaluated by both light and scanning electron microscopy. Results: Dentinal tubules were not covered by a smear layer in the control group, whereas in group 2, a smear layer could be observed in some specimens. In group 3 dentinal tubules were always covered by a layer consisting of granules of about 2 µm. In group 4 all samples showed a layer containing granules of about 5 µm, and in group 5 a thin smear layer could be observed. Conclusion: The use of a polishing fluid containing hydroxylapatite granules during treatment of the root surface results in a granular layer covering the dentinal tubules. This layer may reduce hypersensitivity after ultrasonic subgingival scaling. Keywords: hydroxylapatite, hypersensitivity, smear layer, toothbrush, ultrasonic periodontal treatment, Vector system

Objective: The purpose of this double-blind study was to evaluate the effect of intra-articular opioid injections on postoperative pain and joint mobility after arthrocentesis of the temporomandibular joint (TMJ). Method and Materials: Forty patients suffering from persistent pain in combination with anterior disc displacement (22 with reduction, 18 without reduction) and unresponsive to nonsurgical therapy underwent arthrocentesis of the affected TMJ under local anesthesia. All patients were randomly assigned to 2 groups. In group 1 (20 patients), 1 mL of buprenorphine solution was injected into the joint space at the end of the intervention; in group 2 (20 patients), 1 mL of saline was used. For postoperative pain management, all patients received Paracetamol ad libitum. Preoperatively and at postoperative days 2, 4, 7, and 14, individual pain levels were determined on a visual analogue scale together with maximum mouth opening. Results: At days 2 and 4 after the intervention, remarkable differences were detectable between the 2 groups, showing a rapid normalization of joint mobility and pain scores in group 1; in contrast, improvement in group 2 was delayed. Conclusion: Intra-articular injections of long lasting opioids seem to influence joint mobility and pain positively within the first week after arthrocentesis. Keywords: arthrocentesis, opioids, pain management, temporomandibular joint

Objectives: To analyze the occurrence of symptoms of unerupted mandibular third molars, to investigate associated pathologies, and to determine indications for removal of unerupted mandibular third molars in a Turkish population. Method and Materials: A retrospective study was performed by reviewing 832 patients referred to Gülhane Military Medical Academy Dentistry Center for evaluation of their mandibular third molars. The patients were clinically examined, and unerupted and partially erupted mandibular third molars were determined from radiographs. The symptoms and pathologies associated with these teeth were analyzed. The indications for removal were classified into 10 groups. Results: Two-thirds of the patients were between 20 and 29 years of age. Of the 832 unerupted mandibular third molars found, 557 (66.9%) teeth were partially erupted and 275 (33.1%) were completely unerupted. A total of 521 (62.6%) of all unerupted third molars had no symptoms, while 311 (37.4%) were associated with symptoms. The most frequent complaints of the patients were pain and swelling. Pericoronitis was observed as the most frequent pathology, in 142 patients. Of 832 unerupted mandibular third molars, 582 (69.9%) had complete root formation, 177 (21.2%) had two-thirds root formation, and 73 (8.9%) had one-third root formation. Conclusion: Patients between 20 and 29 years of age had the highest prevalence of unerupted mandibular third molars (69.3%). However, this figure decreased with increasing age. Partially erupted teeth (n = 228) caused the occurrence of symptoms more than completely erupted teeth (n = 83) in a Turkish population. Keywords: impaction, indication, oral surgery, retrospective study, symptom, third molar

Objective: To assess the effect of metal conditioners on the bond strength between resin cements and cast titanium. Method and Materials: Commercially pure titanium (99.56%) was cast using an arc casting machine. Surfaces were finished with 400-grit silicon carbide paper followed by air abrasion with 50-µm aluminum oxide. A piece of double-coated tape with a 4-mm circular hole was then positioned on the metal surface to control the area of the bond. The prepared surfaces were then divided into 4 groups (n=10): G1, unprimed Panavia F; G2, Alloy Primer-Panavia F; G3, unprimed Bistite DC; G4, Metaltite-Bistite DC. Forty minutes after insertion of the resin cements, the specimens were detached from the mold and stored in water at 37°C for 24 hours. Shear bond strength was performed in a testing machine (MTS 810) at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukey's test with a .05 significance level. The fractured surfaces were observed through an optical microscope at 103 magnification. Results: The G1 group demonstrated significantly higher shear bond strength (17.95 MPa) than the other groups. G3 (13.79 MPa) and G4 (12.98 MPa) showed similar mean values to each other and were statistically superior to G2 (9.31 MPa). Debonded surfaces generally presented adhesive failure between metal surfaces and resin cements. Conclusion: While the Metaltite conditioner did not influence the bond strength of the Bistite DC cement, the Alloy Primer conditioner significantly decreased the mean bond strength of the Panavia F cement. Keywords: fixed partial denture, metal conditioners, resin cements, shear bond strength, titanium

Objective: The purpose of this in vitro study was to determine the fracture resistance of 3 core materials (silver amalgam, resin composite, glass-ionomer cement) supported by 1 custom cast post (nickel-chromium alloy) and 2 prefabricated posts (Radix and Safix posts). Method and Materials: A sum of 45 recently extracted single-rooted human incisors and canines were placed in 0.5% sodium hypochlorite. Before the experiments, the anatomic crowns of teeth were removed below the cementoenamel junction to obtain a standard root length. The roots were endodontically treated by the manual condensation method. The teeth were randomly divided into 9 groups with 5 samples per group.The posts were luted in the corresponding root canals with zinc polycarboxylate cement. Each core reconstruction was prepared with diamond instruments, and the height of cores formed was 6.0 mm. The tooth and post-core combinations were mounted in acrylic resin blocks. Each tooth and post-core combination was placed in a special jig at a 45-degree angle to the buccal/lingual axis and then subjected to a load on an electronic pull-tension-compression testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed using one-way analysis of variance. Results: The resistance to fracture for prefabricated posts was significantly higher for resin composite core than for the other post-core combinations (P < .001). For prefabricated posts, the composite core and amalgam core materials were significantly stronger than the glass-ionomer core material (P < .001). The differences between the core materials were statistically significant (P < .001). Conclusion: The glass-ionomer core with custom post was the weakest post-core system, while the prefabricated posts (Safix and Radix) with resin composite and amalgam cores were the strongest post-core systems. Keywords: core materials, fracture resistance, post-core combinations, post designs, post materials

Bell palsy in a patient who had a hanging lower lip. A prosthetic appliance anchored to the teeth was fabricated to maintain the lip in its normal position, thereby helping the patient to perform normal functions. Keywords: bilateral Bell palsy, facial palsy, hanging lower lip, lip-support prosthesis

Objective: The purpose of this study was to clinically evaluate an anesthetic technique in which a second cartridge was reloaded in a traditional dental syringe and reinjected at the same site in regard to success rate of the attempted inferior alveolar nerve block. During the same appointment, a computer-controlled delivery system was used on the opposite side of the same patient to administer 2 cartridges as well. Successful anesthesia and time efficiency of the traditional syringe and computer-controlled technique were then evaluated and compared. Method and Materials: Thirty-five subjects between the ages of 18 and 58 years were randomly assigned to both the traditional syringe delivery system using a standardized 2-cartridge reloading and reinjection technique and a computer-controlled system using a technique whereby the second cartridge was reloaded without having to remove the needle from the injection site. Subjects served as their own controls. Successful anesthesia was achieved when all soft tissues innervated by the inferior alveolar and lingual nerves were nonresponsive to painful stimulation with an explorer as evaluated at 3- and 10-minute intervals following final anesthetic administration. The time necessary to reload the second cartridge for each side was measured, as was the time necessary to deliver the second full 1.8-mL cartridge. Results: Two-cartridge delivery with the traditional syringe resulted in a 94.3% success rate at 3 minutes and a 100% success rate at 10 minutes; 2-cartridge delivery with the computer-controlled delivery system resulted in an 80% success rate at 3 minutes and a 91.4% success rate at 10 minutes following final injection. Reloading time for the second cartridge was 11.37 seconds less with the computer-controlled delivery system, but no statistical difference was found between the 2 systems regarding time to deliver the second cartridge. Conclusions: The results for the 2-cartridge technique with both systems compare favorably with and surpass the accepted 85% success rate reported in the dental literature with only 1 cartridge. The computer-controlled delivery system did not require needle removal and was more time efficient at reloading than the traditional syringe system. Keywords: computer-controlled delivery system, dental anesthesia, inferior alveolar nerve block, local anesthesia, success rate, two-cartridge injection