Bilateral root or root canal aberrations in a dental school patient population.

Clinicians have often noted that aberrant root morphology in a given tooth is also observed with varying degrees of frequency in the corresponding contralateral tooth. The purpose of this study was to determine the proportion of bilateral morphological root aberrations in a random sample of adult human dentition. Five hundred one dental records were selected from the retired record section at the University of Oklahoma College of Dentistry and their full-mouth radiographs were reviewed for aberrant root canal morphology. Bifurcation of the canal in mandibular first premolars was the most common finding (22.8% of patients), with 60% of these being bilateral. Maxillary anterior teeth had the least aberrations. It was observed that unusual root morphology is bilateral approximately 60% of the time. Therefore, the incidence of root or root canal abnormalities reported by the percentage of patients involved will always exceed the incidence of abnormalities reported by type of tooth (e.g. mandibular or canine) involved except for abnormalities which are found bilaterally in 100% of the patients studied. Radiographic interpretation appears to result in a lower incidence of anatomical aberrations than direct identification. The more rare the aberration, the more likely it is to be bilateral in occurrence.

Histomorphometric comparison of canals prepared by four techniques.

Numerous methods of root canal preparation have been recommended and used by clinicians. This study used histomorphometrics to determine the area of root canal preparations using four currently popular techniques. Clinicians that were highly skilled in each technique prepared curved canals in acrylic blocks. Each clinician described this technique and discussed the technique with regard to the use of acrylic blocks as compared with dentin. Analysis of the areas of the root canals after preparation revealed a significant difference among the groups. The mean areas after treatment were step-back technique, 17.33 mm2; Cavi-Endo technique, 15.87 mm2; Canal Master technique, 13.56 mm2; and balanced force technique, 17.31 mm2. Photographs of the blocks used in the study were included for inspection by the reader.

A standard predetermined endodontic preparation concept.

Cleaning and shaping the root canal system is the most tedious and demanding phase of endodontic therapy. Using a predetermined endodontic preparation allows for a routine approach to instrumentation and produces high-quality results with better efficiency. Schilder states, "Inherent in the concept of cleaning and shaping is the fact that each root canal system, like each carious lesion, is different from another and that, within certain prescribed guidelines no two root canal preparations should be exactly alike, anymore than any two intracoronal preparations are exactly alike." The concept of predetermined preparation does not conflict with Schilder's statement, it merely refines prescribed instrumentation guidelines and establishes instrumenting parameters. The goals of endodontic instrumentation are to: (1) instrument with control so that there is enlargement without deviation from the original canal; (2) instrument to a size that is consistent with total mechanical and chemical debridement; (3) debride the root canal system from its coronal orifice to the periodontal ligament, regardless of canal curvature; and (4) create a canal shape that tapers from the coronal orifice to the apical opening. The authors will discuss each endodontic goal as it is accomplished in the predetermined preparation. Techniques for instrumenting to the predetermined sizes are also described.

Endodontic management of trauma to permanent teeth.

Oral trauma is a common event. It has been estimated that up to 20% of the United States population has sustained injuries to the teeth. In a perspective study, Andreasen reported that one of every two Danish children had sustained an oral injury by age 14. This article will discuss the different types of injuries that can happen to permanent teeth, endodontic management of these injuries, and possible complications. Exarticulations (totally avulsed teeth) will not be thoroughly discussed.

Endodontics: errors in instrumentation.

The authors provide a pictorial review of technical errors in endodontic instrumentation. Examples of separated instruments, abrupt constriction, laceration, canal transportation, and control zone errors are provided. The potential problems and effect on prognosis associated with these errors are explained.

Sodium hypochlorite injection into periapical tissues.

Sodium hypochlorite is a useful adjunct to endodontic therapy but it must be confined to the root canal. A case of periapical injection of hypochlorite with untoward sequellae is presented.

Combined endodontic and restorative treatment considerations.

Endodontic treatment for pulpal pathology should result in an asymptomatic tooth with a sealed canal. Restorative treatment for the pulpless tooth should provide protection against fracture and the needed resistance against masticatory stress to allow the tooth to resume normal function.