Anesthesia for endodontic practice.

The ability to provide excellent, high-quality pain control in endodontic practice is based on a practical knowledge of the indications and limits of intraoral local anesthesia. This article reviews clinically relevant aspects of anatomy, physiology, and pharmacology that contribute to the effective use of local anesthesia.

Plain and buffered lidocaine for neonatal circumcision.

OBJECTIVE: To determine if buffered lidocaine provided a more effective nerve block in a short time than plain lidocaine for neonatal circumcision. METHODS: One hundred ninety-four newborn males were studied in a randomized trial using two dorsal penile nerve block preparations for circumcision. Ninety-two received plain lidocaine, and 102 received buffered lidocaine. The infants were evaluated at timed intervals before the procedure, during anesthetic injection, and during circumcision. Objective measurements of heart rate and oxygen saturation, and subjective determinations of behavioral state were recorded. Using heart rate as the major outcome variable, it was determined that 65 subjects per group would be needed to achieve a power of .08. Complications also were noted. RESULTS: Heart rates and oxygen saturations were similar in the two groups at each timed interval. The behavioral characteristics and amount of crying also were comparable in both groups. The only complication was minor bleeding, seen in each group. CONCLUSION: Adding a buffering agent to lidocaine did not provide a more effective level of anesthesia in a short time.

Managing the endodontic patient with disabling anxiety or phobia.

Disabling anxiety and phobia are commonly encountered in dental practice. Successful management of these patients is especially important in endodontic practice, where patients are often compelled to seek treatment because of acute or threatened pain. This article reviews the recognition and management of these common disorders. Mild anxiety can be managed with oral sedatives and/or nitrous oxide; however, moderate to severe anxiety and phobia is best treated with deep sedation or general anesthesia.

Immunohistochemical study of gamma-aminobutyric acid and bombesin/gastrin releasing peptide in human dental pulp.

This study investigated the presence of the putative peripheral neuromodulators Gamma-aminobutyric Acid (GABA) and Bombesin/Gastrin-Releasing Peptide (BN/GRP) in the human tooth pulp. Caries free and asymptomatic carious teeth were processed for paraffin embedding and sectioned at six microns. From each specimen, sections were stained with hematoxylin and eosin; other sections were subjected to Avidin-Biotin-Peroxidase Complex immunohistochemistry for GABA and BN/GRP. Sections of rat brain and small cell lung carcinoma served as positive controls. Results indicate the presence of specific GABA-like and BN/GRP-like immunoreactivity within the pulps of both normal and carious teeth. Overall staining for both ligands was significantly more intense within inflamed pulps. Based on their actions elsewhere, GABA and BN/GRP may play a role in the dental pulp as peripheral neuromodulators or as growth factors.

An in vitro study of apical extrusion of sodium hypochlorite during endodontic canal preparation.

One hundred fifty-three single rooted teeth were divided into four groups. Canals were cleaned and shaped using the balanced forces technique. In one group of 50 teeth, irrigation was delivered with the irrigation needle deep within the root canal. In the other group of 51 teeth, the needle was placed passively in the coronal access cavity and the irrigation carried into the root canal during filing. The remaining 52 teeth in the control groups were treated in the same manner using distilled water as the irrigation solution. The concentration of sodium extruded apically was measured by means of atomic emission spectrophotometry, and the volume of sodium hypochlorite extruded was calculated. Significantly more sodium hypochlorite was extruded apically during deep delivery of the irrigation (p<0.05). It is concluded that the use of a reservoir of irrigation in the coronal access cavity results in significantly less apical extrusion of irrigation solution than with deep delivery.

Evaluation of an apatite cement as a root end filling material.

A self-setting apatite cement, EBA cement, and amalgam with varnish were tested for root end sealing ability using a fluid filtration and dye technique. Single-rooted human teeth were prepared in vitro to receive root end fillings. Experimental groups were amalgam with two layers of varnish, EBA cement with dry cavity, EBA cement within a wet cavity, apatite cement within a dry cavity, and apatite cement within a wet cavity. Fluid filtration measurements were made at 6, 24, and 7 days, and 1 and 3 months. Each specimen was also subjected to a dye leakage test using Procion Green dye at 3 months. Results indicated that apatite cement provided a comparable seal to amalgam and EBA cement. This finding, in conjunction with its excellent biocompatibility, suggests that apatite cement is an acceptable alternative to present-day root end filling materials.

Interpretation of endodontic file lengths using RadioVisiography.

The purpose of this investigation was to compare RadioVisioGraphy (RVG) imaging with conventional radiography in determining endodontic file length adjustment. Human cadaver sections with first or second molars were used. Files were inserted into canals at randomly selected lengths, from 4 mm short of the radiographic apex to 3 mm beyond. Radiographs and RVG images were evaluated to determine the adjustment needed to place the file 0.5 mm from the radiographic apex. Results showed no significant difference in the ability of endodontists to make accurate file length adjustments using conventional radiography versus RVG. In this study, it was found that: (a) accurate file length adjustments can be made from an image two times larger than the actual tooth; (b) RVG is not significantly better than conventional radiography; and (c) if both methods are available, RVG is preferred because of the significant reduction in radiation dose.

Interpretation of periapical lesions using RadioVisioGraphy.

Density and gray-scale changes in radiographs are important visual features the clinician uses to evaluate changes in bone pattern. With the advent of a new direct digital radiology system, RadioVisioGraphy (RVG), the controlled adjustment of contrast is now possible. The purpose of this study was to compare RVG's diagnostic potential for detecting periapical lesions with that of conventional radiography. Lesions were created in human cadaver specimens and radiographed conventionally and with RVG. Images were evaluated by three endodontists. Results were: (a) when no lesion existed, conventional radiographs were more diagnostic than RVG at a significance level at p < or = 0.05; (b) when lesions were enlarged to involve lamina dura and medullary bone, RVG was superior at p < or = 0.05; and (c) no difference was found between conventional radiography and RVG when the lesion involved cortical bone.

Effect of root canal treatments on dentin permeability.

Calcium hydroxide has been used to slow or reverse external root resorption subsequent to trauma. In this study, an experimental model was established to study the diffusion of calcium ions from the canal to the root periphery after various intracanal treatments. Analyses of calcium ion concentrations from extraradicular samples revealed that dentin specimens varied in their rates of diffusion of calcium and that treatment of the canals with various agents affected the amounts of calcium recovered.

Pseudocyst of the maxillary sinus.

A case report is presented involving the endodontic retreatment of a maxillary second molar associated with a sinus radiopacity. Disappearance of sinus pathosis occurred within 6 days after root canal debridement. A direct relationship between apical pathosis and a pseudocyst of the maxillary sinus is suggested. Thirteen-month recall shows no recurrence.

Trauma involving the dentition and supporting tissues.

Successful treatment of traumatic injuries depends on timely action by the patient and a quick and accurate diagnosis by the dentist. Although most injuries are minor and of an urgent nature, displaced or missing teeth are true emergencies. The mismanagement of dental traumatic injuries has provided much information as well as questions for research that have resulted in the increased retention of teeth with as little treatment as possible. Maintaining pulp vitality when possible, utilizing the therapeutic effects of calcium hydroxide, and returning teeth to function as soon as possible are keys to predictable prognosis.

Histological examination of paraformaldehyde-exposed gutta-percha implanted in rats.

Adsorption of some paraformaldehyde was noted in a previous study evaluating its sterilizing effect on gutta-percha (GP). This study examined histologically the effect of this adsorption when formaldehyde-exposed GP was implanted into the subcutaneous connective tissue of rats. GP implants were prepared in cylinder shape using a template designed to standardize size. Fifty GP cylinders were exposed to paraformaldehyde for 7 days before being implanted, while 50 others were implanted without exposure. Fifty rats had two implant sites prepared, at dorsal-interscapular and dorsal-caudal regions. Sham operations were performed on 10 rats to examine the effect of the surgery itself. The animals were killed at 4, 7, 14, 28, and 56 days. There was a significant difference between the two categories of implants only at 7 days, with the GP specimens without paraformaldehyde exposure showing more inflammation than GP with paraformaldehyde specimens (p = 0.043). Although the GP-alone specimens showed greater initial inflammation, both groups recovered in the same time period. One of the GP specimens with paraformaldehyde still showed a moderate/severe response at 56 days, whereas all of the GP-alone specimens showed only none/mild responses. The GP examined appeared to cause more inflammation than was expected.

An analysis of success and failure of apicoectomies.

The radiographs from 715 patient charts were analyzed to study the effect of 11 factors on the success and failure of apicoectomies. Of these, 424 had recall radiographs of 6 months or more and were evaluated for changes in radiolucencies. The data were analyzed by cross-tabulation and chi-square analysis for significant relationships. Complete healing was found in 65% of the recall cases, while incomplete and unsatisfactory healing occurred in 29.4% and 5.6% of the cases, respectively. Complete healing was found to increase with patient age. Those over 60 yr of age had the highest percentage of complete healing. No statistical difference in healing was found between maxillary and mandibular teeth. Also, postsurgical healing associated with those teeth which were inadequately obturated with gutta-percha, silver points, or paste-filling materials did not differ significantly. No significant difference in healing was found between the teeth that were retreated nonsurgically before surgery and those that were not. Healing was independent of the placement of a retrofilling as well as the type of retrofilling period. Significantly better healing was seen with teeth that were permanently restored following surgery.

Radiographic interpretation of endodontic file length.

The purpose of this study was to evaluate the accuracy of examiners when asked to make file length adjustments with only a radiograph. The examiners viewed several radiographs under proper viewing conditions but without the aid of measuring devices. Two files of varying lengths (sizes 10 and 15) were placed in maxillary and mandibular premolars and molars from cadavers. The nine examiners were 67.91% in agreement of actual file length adjustment needed when adjustments of up to 0.5 mm were needed, 17.76% when adjustments of from 0.5 up to 1.0 mm were needed, and 14.33% when adjustments of greater than 1.0 mm were needed.

The comparative antimicrobial effect of calcium hydroxide.

The antimicrobial effectiveness of calcium hydroxide, camphorated paramonochlorophenol, and formocresol in root canals of extracted human teeth was compared. Canals in single-rooted teeth were enlarged and inoculated with Streptococcus mutans, Actinomyces viscosus, and Bacteroides gingivalis or Bacteroides fragilis. After treatment with a test agent and sealing and incubation for 1 hour, the canal contents were analyzed for the number of viable test bacteria and compared with that of inoculated teeth not treated with test agents. All test agents exhibited antimicrobial activity against all bacteria, with percent reductions in viable bacteria ranging from 64.3% to 100%. The combined data for Pulpdent paste and calcium hydroxide showed significantly higher antimicrobial activity than the combined data for camphorated paramonochlorophenol and formocresol for S. mutans and B. gingivalis or B. fragilis but showed no difference for A. viscosus.

Human saliva coronal microleakage in obturated root canals: an in vitro study.

This study assessed salivary penetration through obturated root canals as related to time by using two methods of analysis--histological examination and dye penetrations. A total of 160 human maxillary anterior teeth were instrumented to size 60 Hedstrom file. Ten of the teeth were not obturated; 150 teeth were obturated by lateral condensation of gutta-percha and Roth's root canal sealer. Fifty of these teeth received intermediate restorative material temporaries to a thickness of approximately 3 mm. All teeth were immersed in 50 ml of whole human saliva and kept at 37 degrees C and 100% humidity. The saliva was changed daily. At 2, 7, 14, 28, and 90 days, 32 teeth were removed from the saliva. Of these, two were unobturated and were examined for bacterial penetration by culturing of the apical one-third. Ten teeth without temporaries were immersed in Pelikan ink for 2 days to demonstrate the extent of salivary penetration. These teeth were decalcified and cleared to allow direct measurement of dye penetration. Decalcified serial 7-microns-thick sections were prepared from the remaining 20 teeth, 10 with and 10 without intermediate restorative material temporaries. The sections were stained with hematoxylin and eosin stain and Brown and Hopps stain. Saliva penetration assessed in histological sections was significantly less than was visualized with dye analysis. Salivary penetration at 3 months was significantly greater than at the four earlier study periods. This amount of salivary penetration was considered to be clinically significant. The results strongly suggest retreatment of obturated root canals that have been exposed to the oral cavity for at least 3 months.

A clinical evaluation of the Endocater--an electronic apex locator.

The purpose of this study was to evaluate the accuracy of an electronic apex locator, the Endocater, in determining the location of the apical constriction or cementodentinal junction (CDJ). Measurements made by the Endocater were also compared with the adjustments recommended by an experienced endodontist. A total of 69 teeth with 99 canals from nine patients were evaluated. The results indicated that the evaluator was 95.8% and the Endocater 67.7% accurate in positioning the probe within +/- 1.000 mm from the CDJ. Thirty-three canals or 34.4% appeared to be clinically acceptable radiographically and no adjustments were deemed necessary by the evaluator. There was a significant difference (p less than 0.003) between the evaluator's ability to adjust the electronically generated file length radiograph to acceptable clinical standards and the Endocater's ability to determine the location of the CDJ. A total of 59 canals (59.6%) of the electronically determined working lengths were beyond the CDJ (n = 99). In 27 canals, the tip of the probe was greater than 1 mm beyond the constriction. Without radiographs to confirm working lengths, many canals in this study would have been overinstrumented. Future research with electronic apex locators is needed before accepting the technique as a substitution for radiographic working length determination.

An in vivo study of the use of a nonresorbable ceramic hydroxyapatite as an alloplastic graft material in periapical surgery.

This study evaluated reactions to a hydroxyapatite after endodontic treatment and periapical surgery. Thirty-eight root canals in two Macaca speciosa monkeys were endodontically treated. Apicoectomy was then performed, leaving bony defects at the apex of each root. The defects were either packed with Durapatite ceramic crystals or allowed to fill with blood. Each animal received at least one dose of Procion red, a hard-tissue marking agent. After healing periods of 2 to 6 months, the apices were examined clinically, radiographically, and histologically. The ceramic material was well tolerated clinically with no gross evidence of inflammation or rejection. Histologically, the material was biocompatible. Healing of the experimental sites consisted of an initial investment of the apatite crystals in fibrous connective tissue followed by eventual replacement of the connective tissue with bone. Despite its excellent biocompatibility, the material appeared to retard osteogenesis by its physical presence. Although the ceramic eventually became entrapped in bone, without an intervening layer of connective tissue, there was a significantly greater amount of new bone in control sites.