Dentinal Tubule Penetration of a Calcium Silicate-based Root Canal Sealer with Different Obturation Methods.

INTRODUCTION: The purpose of this study was to investigate the depths of penetration of a calcium silicate-based sealer in dentinal tubules by using 3 different obturation methods. METHODS: One hundred extracted human permanent anterior teeth were endodontically prepared and divided equally into 3 experimental groups and 1 control group as follows: CPoint single cone (CPSC), gutta-percha single cone (GPSC), gutta-percha vertical condensation (GPVC), all with a calcium silicate-based sealer and calcium indicator Fluo-3, and CPoint single cone with a calcium indicator Fluo-3 (CPF3) without sealer as the control. The roots of the teeth in each group were axially cross-sectioned, and the surfaces were examined under confocal laser scanning microscopy at ×10 and ×20 magnifications. The sealer penetration depths were measured at their maximum depths and at 4 circumferential depths (12, 3, 6, and 9 o'clock) by using fluorescence. RESULTS: Statistical analyses by using one-way analysis of variance and repeated measures analysis with linear mixed models showed no statistically significant difference among the mean maximum depth measurements (CPSC, 283.83 µm; GPSC, 318.66 µm; and GPVC, 313.03 µm; P = .7553) and among the average depths across all points (CPSC, 111.24 µm; GPSC, 135.38 µm; and GPVC, 126.62 µm; P = .5304) for the 3 experimental groups. CONCLUSIONS: The pressure derived from hygroscopic expansion of CPoint or warm vertical condensation did not enhance penetration depths of the calcium silicate-based sealer. Sealer penetration into the dentinal tubules occurred independent of the obturation technique.

Evaluation of a calcium silicate-based cement as a root reinforcement material for endodontically treated maxillary anterior teeth.

STATEMENT OF PROBLEM: Fractures of endodontically treated teeth have been attributed to weakened tooth structure caused by root canal enlargement and post preparation. PURPOSE: The purpose of this in vitro study was to evaluate the fracture resistance of roots filled with either gutta percha, composite resin (LuxaCore Dual), or calcium silicate-based cement (Biodentine). MATERIAL AND METHODS: One hundred twenty freshly extracted, human, permanent maxillary anterior teeth were sorted by type and assigned to 1 of 4 groups (n=30). The teeth in group NT were not endodontically treated and served as the control. The teeth in groups GP, LC, and, BD were accessed and instrumented to size 40/06. In group GP, the root canals were completely filled with gutta percha. In groups LC and BD, only the apical 5-mm portion of the root canals was filled with gutta percha, and the remaining portion of the root canals was filled with (LuxaCore Dual) in group LC and with (Biodentine) in group BD. Fracture resistance (kN) was assessed at the middle portion of each root, using a 3-point bending test with a universal testing machine exerting a compressive load on a loading pin at a crosshead speed of 0.5 mm/min until fracture occurred. One-way ANOVA was used to compare the mean root fracture resistance among the 4 groups (α=.05). RESULTS: The mean ± SD fracture loads were 2.13 ±0.53 kN for group NT, 1.97 ±0.60 kN for group GP, 2.18 ±0.71 kN for group LC, and 2.22 ±0.54 kN for group BD. No statistically significant differences were found among the 4 groups (P>.05). CONCLUSIONS: The roots of endodontically treated maxillary anterior permanent incisors filled with gutta percha, Biodentine, or LuxaCore Dual had resistance to fracture similar to that of teeth that were not endodontically treated.

Osteomyelitis of the Mandible in an Adolescent.

A 13-year-old female, who had been experiencing episodes of mandibular pain and swelling for approximately six months, was referred to a university urgent care dental clinic for evaluation after receiving endodontic treatment. At the referral examination, clinical and radiographic findings were suggestive of osteomyelitis. The purpose of this report is to present the possible etiology, clinical and radiographic findings and surgical management of mandibular osteomyelitis in an adolescent patient.

Cytotoxicity and alkaline phosphatase activity evaluation of endosequence root repair material.

INTRODUCTION: The purpose of this in vitro study was to evaluate the cytotoxicity and alkaline phosphatase (ALP) activity of a new bioceramic root repair material, EndoSequence Root Repair Material (ESRRM; Brasseler USA, Savannah, GA), and to compare these characteristics with those of ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK) and Geristore (GR; Den-Mat LLC, Santa Maria, CA). METHODS: Human Saos-2 osteoblast-like cells were exposed to 1-, 3-, and 7-day elutes of the materials (100% and 50% strength) for 24 hours after which the bioactivity and ALP activity of the cells were evaluated using a methylthiazol sulfophenyl (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and para-Nitrophenylphosphate colorimetric assay, respectively. In the positive control group, Triton X-100 (Boehringer Mannheim Corp, Indianapolis, IN) was used to lyse the cells, representing 100% cytotoxicity, and in the negative control group cells received fresh culture medium only. Data were statistically analyzed using the unpaired t test and 1-way analysis of variance. RESULTS: The results revealed that the bioactivity of the cells as well as ALP activity were significantly decreased after exposure to ESRRM elutes in almost all time periods, both in 100% and 50% concentrations, with the exception of ALP activity of day 1 elutes of ESRRM at 50% concentration. MTA did not change the bioactivity or ALP activity of the cells. GR elutes of 100% concentration reduced the bioactivity on days 1 and 3, whereas GR elutes of 50% concentration affected the cells only on day 1. None of the GR elutes had any effect on ALP activity of the cells. CONCLUSIONS: It was concluded that ESRRM elutes of all time periods in general reduced the bioactivity and ALP activity of osteoblast-like cells. GR reduced bioactivity only, whereas MTA had no effect on the cells.

Retention of teeth versus extraction and implant placement: treatment preferences of dental faculty and dental students.

The purpose of this study was to determine the treatment preferences amongst dental faculty and dental students for either retention of teeth by endodontic and restorative treatment or extraction and implant placement. A survey of 134 general dentistry faculty and 253 senior (fourth-year) dental students was conducted in a university college of dentistry. Participants completed a survey consisting of questions for which one of two choices could be selected. For questions describing specific clinical situations, dental faculty and dental students more frequently selected endodontic and restorative treatment over extraction and implant placement. However, dental students selected implants more frequently than dental faculty, and more recent graduates on the dental faculty selected implants more frequently than less recent graduates on the dental faculty. In addition, there was an increase in the selection of implants, for all participant groups, as the prosthetic and endodontic complexities of the clinical situations increased. Participants were more likely to select endodontics rather than implants for medically compromised patients, and an implant was overwhelmingly selected over a fixed bridge for the replacement of a single tooth unit. In conclusion, the findings of this study indicate that retention of teeth is preferred, but there may be an increased preference toward implants in the future.

A dozen ways to prevent nickel-titanium rotary instrument fracture.

BACKGROUND: and Overview. With the increased use of nickel-titanium (NiTi) rotary instruments for root canal preparation in endodontics, instrument fracture has become more prevalent. Extensive research has been conducted on the physical properties and mechanical characteristics of NiTi rotary instruments, as well as the factors that can contribute to instrument failure. NiTi rotary instruments are subjected to torque and are susceptible to cyclic fatigue, which are the main causes of instrument fracture. However, with an understanding of how these instruments function in preparing root canals and by applying ways to reduce torque-generated metal fatigue, clinicians can use the instruments safely in clinical practice. RESULTS: The author presents 12 measures that clinicians can take to prevent NiTi rotary instrument fracture and discusses them in detail. CLINICAL IMPLICATIONS: NiTi rotary instrument fracture complicates the progress, and compromises the prognosis of endodontic treatment. However, when clinicians take appropriate measures, rotary instrument fractures can be prevented.

Histological study of periradicular tissue responses to uninfected and infected devitalized pulps in dogs.

Uninfected necrotic tissue, such as that which follows a myocardial or cerebral infarct, is capable of inducing an inflammatory reaction. Eventually, the infarct is organized by granulation tissue. Why then, does uninfected devitalized pulp tissue, such as in traumatized teeth, not cause periradicular inflammation and does not become organized by granulation tissue? Four beagle dogs were used in this experiment. A total of 48 teeth, which included 24 maxillary and 24 mandibular incisors, were aseptically devitalized, leaving residual pulp tissues in the root canals, and equally divided into two groups. Group A (24 uninfected): A sterile cotton pellet was placed deep into the canal orifice before the pulp chamber and access opening were closed with a layer of zinc-oxide eugenol cement followed by glass ionomer cement. Group B (24 infected): The teeth were left open to the oral cavity for 7 days and then closed with a cotton pellet and zinc-oxide eugenol and glass ionomer cement. The animals were sacrificed one year after the experiment and prepared for histological examination of periradicular tissue responses to uninfected and infected devitalized pulp tissues. The results indicate that uninfected devitalized pulp tissues did not continuously release inflammatory mediators and cause persistent periradicular inflammation over a period of one year. However, infected devitalized pulp tissues induced various degrees of periradicular inflammation. Only the apical few millimeters of uninfected devitalized pulp tissue in the root canals were organized by granulation tissue from vital periodontal ligament tissue.