Superfast Set, Strong and Less Degradable Mineral Trioxide Aggregate Cement.

PURPOSE: Despite the good sealing ability and biocompatibility of mineral trioxide aggregate (MTA), its slow setting, high degradation, and weakness limit its use in surgical endodontics and high stress-bearing areas. This study aimed to develop two new liquids to control these drawbacks. They were prepared from calcium chloride, fumed silica, and hydroxyapatite or calcium phosphate and coded "H" and "P," respectively. METHODS: Portland cement, Grey ProRoot® MTA, and white ProRoot MTA were mixed with distilled water (control) or liquid "H" or "P." The pH, setting time, degradation rate, leachant/precipitate' composition, compressive strength, and morphology were assessed. RESULTS: Both liquids maintained MTA's high alkalinity and reduced the setting time by 1-2 orders of magnitude. Both liquids, H in particular, significantly reduced the degradation rate of Grey ProRoot and White ProRoot MTA®. Calcite has been identified as the main phase of the leachant or precipitate formed during the cement's degradation. Calcium hydroxide or hydroxyapatite was also identified with Grey ProRoot MTA mixed with H liquid. These liquids also significantly increased the compressive strength with no statistical differences between them; this was associated with the production of dense, consolidated structures. CONCLUSIONS: The modified MTA could be used in surgical endodontics and high stress-bearing areas.

Comparison of 3 intranasal mists for anesthetizing maxillary teeth in adults: A randomized, double-masked, multicenter phase 3 clinical trial.

BACKGROUND: This double-masked, parallel-design, clinical trial assessed whether a combination nasal spray (K305; 3% tetracaine hydrochloride and 0.05% oxymetazoline hydrochloride) compared with a tetracaine-only spray and a placebo spray would be safer and superior in producing local anesthesia sufficient to complete a direct restorative procedure in maxillary nonmolar teeth. METHODS: The authors randomized eligible patients to receive K305 spray (n = 44), tetracaine hydrochloride spray (n = 44), or a placebo solution (n = 22). The authors compared the incidence of the primary efficacy end point-completion of the procedure without rescue local anesthetic-by means of a 1-tailed Fisher exact test. RESULTS: The end point incidence was 84.1% (95% confidence interval [CI], 69.9-93.4) with K305, 27.3% (95% CI, 15.0-42.8) with tetracaine only, and 27.3% (95% CI, 10.7-50.2) with placebo (P < .001 for K305 versus tetracaine only and versus placebo). Combination spray was associated with statistically significant but transient increases in blood pressure. The most frequent adverse events were rhinorrhea and nasal congestion, which resolved within 2 hours after treatment and occurred more often in the K305 group and tetracaine-only group. CONCLUSIONS: In this study population, the K305 combination nasal spray was safe and more effective in attaining pulpal anesthesia of maxillary teeth from premolar to premolar compared with tetracaine-only and placebo sprays. PRACTICAL IMPLICATIONS: The combination nasal spray might represent a valuable alternative to injected local anesthetic for patients undergoing invasive maxillary dental procedures. Clinicaltrials.gov: NCT01710787.

Streptococcus gordonii collagen-binding domain protein CbdA may enhance bacterial survival in instrumented root canals ex vivo.

INTRODUCTION: The surface-associated collagen-binding protein Ace of Enterococcus faecalis has been implicated as a virulence factor that contributes to bacterial persistence in endodontic infections. The purpose of this study was to determine if proteins with amino acid sequence similarity to Ace found in more abundant oral streptococci could play a similar role in potentially enhancing endodontic infections. METHODS: A Streptococcus gordonii gene similar to ace was identified by genome sequence searches in silico. An isogenic derivative of strain DL1 with a disruption in the identified gene was constructed by allelic replacement. Parent and mutant strains were characterized for their ability to bind immobilized collagen type 1 in a microtiter plate-binding assay. Survival of the strains in a human tooth ex vivo-instrumented root canal model was compared by inoculating canals with parental or mutant bacteria and determining the colony-forming units (CFUs) recovered at various time points over a 12-day period. RESULTS: The S. gordonii gene, encoding a protein with a conserved collagen-binding domain similar to that of Ace, was designated cbdA. The cbdA-deficient cells were less able to bind collagen type 1 than parental cells (P < .0001). Genetic complementation of the cbdA-deficient strain restored the collagen-binding phenotype. By day 12, significantly fewer (P = .03) cbdA-deficient than parental CFUs were recovered from instrumented canals. CONCLUSIONS: A gene encoding a putative collagen-binding protein was identified in S. gordonii. Fewer S. gordonii cbdA-deficient cells survived ex vivo compared with parental cells, suggesting that collagen-binding proteins may contribute to the persistence of oral streptococci in instrumented root canals.

Identification of incinerated root canal filling materials after exposure to high heat incineration.

With the increase in global terrorism there is a higher probability of having to identify victims of incineration events secondary to incendiary explosive devices. The victims of incineration events challenge forensic odontologists when coronal restorations are no longer present to compile postmortem data. With 40 million root canals being completed annually in the United States, a very large pool of antemortem data is available to the forensic odontologist to make positive identifications. When complete and thorough dental records exist, individuals that have undergone surgical and nonsurgical root canal therapy may have materials present in the canal that may aid in identification. This study provides elemental fingerprints of root canal obturation materials to be utilized as a forensic identification aid. This study used scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) to assess the elemental composition of materials before and after high temperature incineration. Sixteen endodontic materials were analyzed pre-incineration and placed in extracted teeth. The filled teeth were subjected to incineration at 900 degrees C for 30 min to simulate incineration events or cremation. Incinerated materials were radiographed and re-analyzed to determine if they retained their original elemental composition. Endodontic sealers, gutta percha, root-end filling materials, silver points, and separated files were distinguishable in the canal and traceable after incineration. The authors present a fingerprint of the endodontic obturation materials that are capable of withstanding high heat incineration to be used as an aid for postmortem identification. This work represents the initial stage of database generation for root canal filling materials for use as an aid in forensic identification.

A diagnostic challenge: anterior variant of mandibular lingual bone depression.

Mandibular lingual bone depressions are considered to be developmental anomalies and most clinicians are familiar with the posterior variant (known as Stafne's bone cavity) that occurs in lingual mandibular molar regions, adjacent to the submandibular gland and below the mandibular canal. The anterior variant of the mandibular lingual bone depression is an asymptomatic bone cavity that occurs adjacent to the sublingual gland in the anterior mandible. Radiographically, it appears as a well-corticated radiolucency that retains a normal trabecular pattern internally. CT imaging is diagnostic and avoids surgical and sialographic procedures. This article reviews radiographic and CT features of a case involving the anterior variant of mandibular lingual bone depression.