Biocompatibility of accelerated mineral trioxide aggregate in a rat model.

INTRODUCTION: The purpose of this study was to evaluate the biocompatibility of gray mineral trioxide aggregate (MTA) mixed with selected accelerants by examining the inflammatory response through histological analysis after implantation into rat mandibles. METHODS: Sixty rats were randomly divided into experimental groups of calcium chloride (CaCl2), calcium nitrite/nitrate (CaN/N), or calcium formate (CaF) mixed with MTA and compared with controls of MTA mixed with sterile water (MTA control) and unfilled osteotomies. Material was implanted into an osteotomy prepared between the roots of the mandibular molars and the incisors in the mandible. After 2 or 8 weeks, tissues were collected and processed for hematoxylin and eosin staining and light microscopic evaluation. Blinded evaluators graded the inflammatory response along the MTA-bone interface on an ordinal scale. Data were analyzed using the Kruskal-Wallis test, and interobserver agreement was determined by the kappa analysis. RESULTS: Interobserver agreement was good with κ = 0.72. No statistically significant differences were noted between experimental and control groups at the 2-week time point (p > 0.05). At this time, all groups displayed a range of inflammatory responses from none to severe with mostly mild to moderate reactions. At the 8-week time point, the inflammatory reaction of CaF mixed with MTA was statistically different from the controls (p = 0.03). CaCl2 and CaN/N were not statistically different from the controls, and the MTA control displayed no inflammation at this time point. CONCLUSIONS: The findings of this study indicate that MTA mixed with accelerants may be a biocompatible alternative when a rapid set is indicated clinically.

Identify the endodontic treatment modalities.

INTRODUCTION: This paper sought to determine the levels of evidence associated with treatment for specific diagnostic categories and the prognosis of treatment. MATERIALS AND METHODS: A review of the literature was conducted using MEDLINE, PubMed, Google Scholar and the Cochrane Database. The Journal of Endodontics, International Journal of Endodontics, Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology, Endodontic Topics, and Dental Traumatology were also searched. The bibliographies of relevant articles were manually searched. CONCLUSION: The review found a low level of evidence to assess clinical treatment modalities. The development of higher levels of evidence to facilitate the selection of appropriate treatment modalities for each diagnostic category is recommended.

Comparison of nonsurgical root canal treatment and single-tooth implants.

INTRODUCTION: The aim of this review was to compare the differences between nonsurgical root canal treatment and single-tooth implants. With the emerging field of implant dentistry gaining acceptance, the choice to retain a diseased tooth through the use of root canal therapy or extract it and replace the tooth with an implant-supported crown has become controversial. Many practitioners consider the single-tooth implant as a reasonable alternative to the preservation of a diseased tooth. METHODS: An extensive search of the dental literature was accomplished to identify publications related to the differences in root canal therapy and dental implants. Several comparative studies were also considered. RESULTS: The treatment modalities were reviewed with respect to outcome measures and study design, success/failure, functional rehabilitation and psychological differences, complications related to treatment, cost differences, and factors influencing treatment planning considerations. CONCLUSIONS: With the reviewed information in hand, the practitioner should be better prepared to determine which treatment option is most appropriate for each individual patient.

Age- and gender-related differences in the position of the inferior alveolar nerve by using cone beam computed tomography.

INTRODUCTION: Surgical endodontic procedures require precise knowledge of anatomic structures that might be traumatized. The aim of this study was to evaluate whether differences in patient gender or age are predictive of differences in the relative location of the inferior alveolar nerve (IAN) compared with the roots of the mandibular first molar. METHODS: We searched a database of 23,000 small-volume cone beam computed tomography scans and evaluated the first 200 patients that met the following inclusion criteria: (1) age between 30-69 years; (2) known gender (n = 25 males and 25 females for each 10-year age bin); and (3) scans containing the mandibular first molar and IAN. Exclusion criteria consisted of any pathosis that might alter the position of the IAN. Anatomic measurements were made by 2 observers with mutual agreement of any discordant measures. Fourteen measurements (in millimeters) were taken at the level of the IAN and mesial and distal root apices. Data were analyzed by 2-way (age, sex) analysis of variance with Bonferroni post hoc test at P <.05. RESULTS: Regardless of age, females had significantly shorter vertical distances from the IAN to the mesial (P < .01) and distal apices (P < .01) and shorter horizontal distances for total width of mandibular bone at the mesial (P < .01) and distal apices (P < .01). In addition, the overall width of the mandibular bone decreased in both genders from the 3rd-6th decade of life (P < .01). CONCLUSIONS: Collectively, these data indicate that both gender and age are predictive of surgical endodontic anatomic relationships and should be considered in presurgical planning.

A retrospective study comparing clinical outcomes after obturation with Resilon/Epiphany or Gutta-Percha/Kerr sealer.

The purpose of this retrospective study was to evaluate the treatment outcome of root canal systems obturated with gutta-percha and Kerr Pulp Canal Sealer compared with Resilon and Epiphany sealer. One hundred three teeth treated in a private endodontic practice were included in the study. Clinical outcomes (healed versus nonhealed) were assessed by using the Periapical Index determination and clinical evaluation at recall appointments. The magnitude of the association between obturation materials used and outcome measured was evaluated with univariate and multivariate logistic regression analysis. Univariate analysis indicated that pulpal vitality, presence of a preoperative lesion, and length of recall times were statistically significant in predicting the outcome. Logistic regression analysis showed that age, tooth position, and length of recall times were statistically significant in predicting the outcome. Root canal systems obturated with gutta-percha and Kerr Pulp Canal Sealer or Resilon and Epiphany sealer had statistically indistinguishable differences in clinical outcome.

Clinical outcomes of artificial root-end barriers with mineral trioxide aggregate in teeth with immature apices.

The purpose of this retrospective study was to evaluate the clinical outcomes of ProRoot mineral trioxide aggregate used as an artificial apical barrier in teeth with immature apices. Twenty teeth from 19 patients were included in this study. A healed diagnosis was based on periapical index scores of 1 or 2 and no clinical signs or symptoms at recall examinations. Eighty-five percent (17/20) of these teeth were healed, and improvements in periapical index scores at recall appointments were shown to be statistically significant (P < .001, Wilcoxon signed-rank test). Chi-square test indicated that age, gender, primary treatment versus retreatment, presence of preoperative lesion, and differences in recall times did not significantly influence healing outcome. Overall, these results indicated that the mineral trioxide aggregate apical barrier technique is a successful method for obturating teeth with immature apices.

Endodontic applications of cone-beam volumetric tomography.

The ability to assess an area of interest in 3 dimensions might benefit both novice and experienced clinicians alike. High-resolution limited cone-beam volumetric tomography (CBVT) has been designed for dental applications. As opposed to sliced-image data of conventional computed tomography (CT) imaging, CBVT captures a cylindrical volume of data in one acquisition and thus offers distinct advantages over conventional medical CT. These advantages include increased accuracy, higher resolution, scan-time reduction, and dose reduction. Specific endodontic applications of CBVT are being identified as the technology becomes more prevalent. CBVT has great potential to become a valuable tool in the modern endodontic practice. The objectives of this article are to briefly review cone-beam technology and its advantages over medical CT and conventional radiography, to illustrate current and future clinical applications of cone-beam technology in endodontic practice, and to discuss medicolegal considerations pertaining to the acquisition and interpretation of 3-dimensional data.

Measurement of mechanical allodynia and local anesthetic efficacy in patients with irreversible pulpitis and acute periradicular periodontitis.

An essential feature of symptomatic periradicular inflammation is mechanical allodynia, defined as reduced mechanical pain thresholds. A previous study evaluating a new digital force transducer showed that it reliably measures mechanical pain thresholds of teeth with normal periradicular tissues. In this study, we tested the hypothesis that the force transducer quantitatively measures mechanical allodynia in teeth with acute periradicular periodontitis (APP) and detects the effects of local anesthetic injection. Mechanical pain thresholds were measured in patients (n = 30) with irreversible pulpitis (IP) and APP and compared with their contralateral teeth. The results show that the mechanical pain thresholds of teeth with IP and APP were reduced by 77% compared with contralateral control teeth. The administration of local anesthesia reversed the mechanical allodynia by 62%, and significant sex-specific effects were observed. In addition, the normal teeth contralateral to the symptomatic teeth had lower mechanical thresholds than those observed in healthy volunteers, suggesting that central sensitization occurs during this type of odontalgia. Thus, we show that the mechanical pain thresholds are significantly reduced in teeth with IP and APP and that the force transducer has potential application as a diagnostic aid in measuring mechanical allodynia and as an outcome measure in endodontic clinical trials such as pharmacologic studies and mechanistic research.

Iontophoresis significantly increases the trans-dentinal delivery of osteoprotegerin, alendronate, and calcitonin.

The purpose of this study was to evaluate the delivery of alendronate, calcitonin, and osteoprotegerin (OPG) through human dentin by both diffusion and iontophoresis for the potential treatment of invasive cervical resorption. Radiolabeled alendronate, calcitonin, and OPG were added to the top of a split chamber device that contained 1-mm thick dentin disks devoid of a smear layer. Transdentinal movement of medicaments by either random diffusion or application of an iontophoretic current was measured by analysis of gamma emission of effluent fractions. In addition, calcitonin delivery was evaluated at differing magnitudes of current (0-4 mA) by using the aforementioned chamber. Diffusion of all 3 medicaments was minimal. In contrast, the application of a 3-mA iontophoretic gradient significantly increased delivery for all 3 compounds at 10-, 20-, and 30-minute intervals. In addition, a linear increase in permeability was seen for calcitonin as milliamperes were increased from 0 to 4 (r = 0.947), with more than a 100-fold increase in delivery observed with iontophoresis. Delivery of the tested medicaments by using iontophoresis might prove to be a useful technique for treatment of invasive cervical resorption.

Effect of selected accelerants on the physical properties of mineral trioxide aggregate and Portland cement.

To decrease setting time by a clinically significant amount, classic Portland cement accelerators (calcium chloride, calcium nitrite/nitrate, and calcium formate) were added to gray and white mineral trioxide aggregate (MTA) (GMTA, WMTA) as well as to Portland cement (PC). Time to initially set was measured, as well as dimensional stability, temperature during set, and pH. The data were analyzed by one-way analysis of variance and Bonferroni multiple comparison test. It was found that all 3 accelerators significantly accelerated the set of GMTA and PC; only calcium chloride and calcium formate significantly accelerated WMTA. Dimensional stability was not significantly different between control and experimental groups. A statistically significant increase in temperature was observed in one group, but it was considered insignificant clinically (less than 3 degrees C). There were seemingly minor but statistically significant differences in pH between groups set with calcium nitrite/nitrate and calcium formate. The results indicate that GMTA, WMTA, and PC mixed with these accelerators merit further study including evaluation of biocompatibility and sealing ability.

The development of a diagnostic instrument for the measurement of mechanical allodynia.

Mechanical allodynia, defined as a reduction in mechanical pain threshold, is an essential diagnostic feature of inflammation of the periodontal ligament. Traditional methods for measuring mechanical allodynia in a tooth are not quantitative. This study evaluated the reliability of a new bite force transducer to measure mechanical pain thresholds, which might have application as a quantitative diagnostic aid for measuring mechanical allodynia in patients with apical periodontitis. To determine inter-observer reliability, subjects (n = 40) were given standardized instructions before generating maximal bite force on maxillary first molars; readings were then recorded by three examiners for a total of ten readings per examiner. To determine the test-retest reliability, the initial examiner then retested at two different sessions. The intraclass correlation coefficient was fair to substantial for inter-observer reliability (0.3-0.64) and substantial for intra-observer reliability (0.63-0.68). Thus, the force transducer used in our study is a reliable method to measure mechanical pain thresholds in endodontic patients.

The incidence of mechanical allodynia in patients with irreversible pulpitis.

The mechanisms of odontogenic pain are complex and incompletely understood. Cases of irreversible pulpitis are thought to represent a localized inflammatory response to bacterial challenge in dental pulp tissue. The presenting symptoms are classically defined by exaggerated painful episodes to thermal stimuli that may linger after cessation of the stimulus. However, the associated incidence of mechanical allodynia, defined as reduced mechanical pain threshold to masticatory forces, has not been characterized. This study evaluated pain intensity ratings and the presence of mechanical allodynia reported by 993 consecutive dental patients presenting for tooth extraction in a community health center. After clinical and radiographic examinations, the pulpal/periradicular diagnostic categories were normal pulp/normal periradicular (n=792 patients), irreversible pulpitis/normal periradicular (n=86), or irreversible pulpitis/acute periradicular periodontitis (n=115). The rank order for the mean values of pain intensity ratings was irreversible pulpitis/acute periradicular periodontitis > irreversible pulpitis/normal periradicular > normal/normal (p<0.05 for all comparisons). The incidence of mechanical allodynia in patients presenting with irreversible pulpitis was 57.2%, indicating that periradicular mechanical allodynia contributes to early stages of odontogenic pain because of inflammation of vital pulpal tissue.

Treatment of a maxillary molar in a patient presenting with florid cemento-osseous dysplasia: a case report.

A case report of a 49-year-old black woman with florid cemento-osseous dysplasia is presented. Endodontic treatment of a maxillary first molar and a general review of florid cemento-osseous dysplasia are presented. Treatment considerations including diagnosis, difficulty in radiographic interpretation, working length determination, and postoperative concerns are discussed.

Evaluation of ultrasonically placed MTA and fracture resistance with intracanal composite resin in a model of apexification.

The purpose of this study was to evaluate whether intracoronal delivery of an apical barrier of mineral trioxide aggregate (MTA) placed ultrasonically, non-ultrasonically, or ultrasonically with the addition of an intracanal composite resin provided a better seal against bacterial leakage. A second purpose was to determine whether intracanal composite resin or gutta-percha and sealer placed against an apical barrier of MTA provided greater resistance to root fracture. In a standardized in vitro open apex model, MTA was placed as an apical barrier at a thickness of 4 mm, with and without ultrasonic vibration. The barriers were challenged with bacteria exposure within a leakage model, and fracture resistance was assessed with increasing forces applied via an Instron machine. After 45 days, the addition of ultrasonics significantly improved the MTA seal, compared with the non-ultrasonics treatment (Kruskal Wallis nonparametric ANOVA with Dunn multiple comparison test p < 0.05). Bacterial leakage occurred in 6 (33%) of 18 in the non-ultrasonic MTA group, 2 (11%) of 18 in the ultrasonic MTA group, and 1 (6%) of 18 in the ultrasonic MTA-composite group. There were no significant differences at 90 days. A 4-mm thickness of MTA followed with an intracanal composite resin demonstrated a significantly greater resistance to root fracture than MTA followed with gutta-percha and sealer (one-way ANOVA with Newman-Keuls multiple comparison test, p < 0.01). The MTA-gutta-percha group was not significantly different than the MTA unrestored positive control.

The sealing ability and retention characteristics of mineral trioxide aggregate in a model of apexification.

Treatment of the immature pulpless tooth presents both an endodontic and restorative challenge. A more favorable long-term prognosis may be achieved with a mineral trioxide aggregate (MTA) apexification procedure followed by an internal bonding technique. We investigated the efficacy of this treatment option by testing the sealing ability and retention characteristics of MTA when placed as an apical barrier in a standardized in vitro open apex model. MTA was placed as an apical barrier at a thickness of 1 mm or 4 mm, with and without prior calcium hydroxide medication. The barriers were challenged with bacteria exposure within a leakage model and displacement forces on an Instron machine. In the leakage study, 100% of the MTA apical barriers showed bacterial penetration by day 70, compared with 20% of MTA root-end fillings used as controls. The displacement study demonstrated a statistically significant greater resistance to force with a 4-mm thickness of MTA, regardless of calcium hydroxide use. We concluded that it was the intracanal delivery technique and not the MTA that contributed to the leakage observed. MTA shows promise in our proposed treatment option of immature pulpless teeth if the sealing ability can be enhanced by improving the delivery technique.