Evaluation of the prognosis and causes of failure in 182 cases of autogenous tooth transplantation.

OBJECTIVES: Autotransplantation is a viable option for treating missing teeth when a donor tooth is available. The aim of this study was to evaluate the prognosis in addition to the causes of failure in 182 autotransplanted teeth. STUDY DESIGN: A total of 182 cases of autotransplantation were analyzed. All the transplants were performed according to a computer-aided rapid prototyping technique with an average extraoral time of 7.58 minutes. These cases were followed for 2 to 60 months after surgery. The prognosis was divided into 4 groups, complete healing, incomplete healing, uncertain healing, and failure. The initial stability, root resorption, and ankylosis were also analyzed. RESULTS: Most transplanted teeth showed complete healing between postoperative 2 months and 8 months. The transplanted teeth with a good initial stability showed better initial healing than those with a poor initial stability. The average extraoral time was 7.58 min (range: immediately after extraction up to 25 min). There was no relationship (P > .05) between the extraoral time and either root resorption (4 cases, 2.4%) or ankylosis (18 cases, 10.7%) within this experimental time period. Nine cases (4.5%) failed. CONCLUSION: This study showed a 4.5% failure rate during the short to intermediate observation period. Autotransplantation is a very useful method for replacing missing teeth, provided that the extraoral time and other factors are well controlled.     

Smear layer production of K3 and ProFile Ni-Ti rotary instruments in curved root canals: a comparative SEM study.

OBJECTIVE: The aim of this scanning electron microscopic study was to compare the quality and amounts of smear layer generated by 2 brands of nickel-titanium rotary instruments during canal preparation in the apical thirds of curved root canals. STUDY DESIGN: Forty mandibular mesial root canals with intact apex and mean curvature between 30 and 35 degrees were selected for this study. The root canals were randomly divided into 2 instrumentation groups of 15 each. Automated preparation was performed with ProFile (Dentsply Maillefer, Ballaigues, Switzerland; n = 15) and K3 (SybronEndo, Orange, Calif; n = 15) instrumentss using a crown-down technique. As a control group, barbed broaches (Mani; Matsutani Seisakusho, Takanezawa-Machi Tochibi-Ken, Japan; n = 10) were used to extirpate the necrotic pulp tissue from the root canals. All root canals were prepared to size #35. Glyde (File Prep, Dentsply Maillefer) was used as lubricant and 1% sodium hypochlorite solution as irrigant. At the conclusion of the experiments, all roots were split longitudinally and the root canal walls were examined at the apical third from 2 different perspectives using a scanning electron microscope. A 4-category scoring system for assessing the smear layer accumulation was used, and the resulting scores were statistically analyzed. RESULTS: Less smear layer was obtained in the K3 group at the selected apical third of curved root canals (P < .05). However, all instruments left a smear layer. The surface texture of the smear layer, in addition to the depth and the frequency of packed materials into the dentinal tubules, varied with instrument type. CONCLUSIONS: This finding may imply that, compared to ProFile, compression of the remaining smear layer is minimized when using the K3 rotary nickel-titanium system.     

In vitro evaluation of the sealing ability of newly developed calcium phosphate-based root canal sealer

This study compared the sealing ability of newly developed calcium phosphate-based root canal sealers (CAPSEAL I, CAPSEAL II) with other calcium phosphate-based sealer (Sankin Apatite Root Canal Sealer: SARCS I, SARCS III), a resin-based sealer (AH Plus), a ZOE-based sealer (Pulp Canal Sealer EWT), and a calcium hydroxide-based sealer (Sealapex) by using an anaerobic bacterial leakage model with Prevotella nigrescens during a 90-day observation period (n=15/group). SARCS I and III had significantly greater leakage with P. nigrescens than all other groups (P<.05). There was no other statistical difference between the sealers. Field emission-scanning electron microscope observations showed that both CAPSEAL I and II sealers were well-adapted to the canal wall and infiltrated into the dentinal tubules.     

Calcium hydroxide inactivates lipoteichoic acid from Enterococcus faecalis through deacylation of the lipid moiety

Introduction

Lipoteichoic acid (LTA) is a major virulence factor of Enterococcus faecalis that is closely associated with refractory apical periodontitis. Recently, we have shown that calcium hydroxide, a commonly used intracanal medicament, abrogated the ability of LTA to stimulate the production of tumor necrosis factor α in a murine macrophage line, RAW 264.7. Because calcium hydroxide could potentially modify the glycolipid moiety of LTA, we examined if calcium hydroxide inactivates LTA through deacylation of the LTA.

Methods

LTA was prepared from E. faecalis by organic solvent extraction followed by chromatography with the hydrophobic-interaction column and the ion-exchange column. RAW 264.7 cells were stimulated with intact LTA or calcium hydroxide-treated LTA for 24 hours, and the productions of nitric oxide (NO) and chemokines interferon-gamma-induced protein (IP-10) and macrophage inflammatory protein-1α (MIP-1α) were determined. The glycolipid structure of LTA was analyzed using matrix-assisted laser desorption ionization-time of flight mass spectrometry and thin layer chromatography (TLC).

Results

The production of NO, IP-10, and MIP-1α was augmented in LTA-stimulated cells, whereas no such effect was observed upon stimulation with calcium hydroxide-pretreated LTA. Mass spectrometry showed that intact glycolipids of LTA yielded distinct mass peaks at 930 to 1,070 mass over charge (m/z) units, corresponding to dihexosyl-diacylglycerol consisting of two acyl chains with chain lengths of C₁₆ to C₂₂ and with one or two unsaturated double bonds. However, those peaks were not observed in the mass spectra of the calcium hydroxide-treated LTA. Furthermore, free fatty acids released from the calcium hydroxide-treated LTA were detected using TLC.

Conclusion

We suggest that calcium hydroxide attenuates the inflammatory activity of E. faecalis LTA through deacylation of the LTA.     

Identification of Porphyromonas gingivalis lipopolysaccharide-binding proteins in human saliva

Porphyromonas gingivalis causes periodontal diseases and its lipopolysaccharide (LPS) is considered as a major virulence factor responsible for pathogenesis. Since initial recognition of P. gingivalis LPS (Pg.LPS) in the oral cavity might be crucial for the host response, we identified Pg.LPS-binding proteins (Pg.LPS-BPs) using Pg.LPS-immobilized beads and a high-resolution mass spectrometry. LPS purified from P. gingivalis was conjugated onto N-hydroxysuccinimidyl-Sepharose(?) 4 Fast Flow beads. Notably, Pg.LPS-conjugated beads could stimulate Toll-like receptor 2 (TLR2) as determined by a TLR2-depdendent reporter expression system using CHO/CD14/TLR2. In addition, the Pg.LPS-conjugated beads induced the production of inflammatory mediators such as nitric oxide and interferon-gamma-inducible protein-10 in the macrophage cell-line, RAW 264.7. These results imply that Pg.LPS retained its immunological properties during the conjugation process. Then, the Pg.LPS-conjugated beads were mixed with a pool of saliva obtained from nine human subjects to capture Pg.LPS-BPs and molecular identities were determined by LTQ-Orbitrap hybrid fourier transform mass spectrometry. Pg.LPS-BPs captured at high frequencies included alpha-amylase, cystatin, prolactin-inducible protein, lysozyme C, immunoglobulin components, serum albumin, lipocalin-1, and submaxillary gland androgen-regulated protein 3B. These proteins are known to be involved in bacterial adhesion and colonization, anti-microbial functions or modulation of immune responses.     

Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm

Introduction

Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation.

Three-dimensional Analysis of Root Canal Curvature and Direction of Maxillary Lateral Incisors by Using Cone-beam Computed Tomography

Introduction

Root canal curvature can affect the technical quality of endodontic treatment. Prior studies measured canal curvature mainly by 2-dimensional radiography. The aim of this study was to measure the 3-dimensional (3D) root canal curvature and canal direction of maxillary lateral incisors by using cone-beam computed tomography (CBCT) and mathematical modeling.

Methods

The CBCT images of 186 maxillary lateral incisors from 110 patients were used to measure 3D root canal curvature by using V-works and kappa software. In addition, the direction of each root canal was determined by measuring the orientation of the apical one-third with respect to the coronal two-thirds.

Results

All 186 maxillary lateral incisors were found to have canal curvature that was mainly oriented in the disto-palatal direction. The point of maximum curvature was located 0.5 mm from the root apex.

Conclusions

Maxillary lateral incisors have 3D canal curvature that is maximal near the root apex, oriented in the disto-palatal direction. These CBCT analyses provide valuable information for root canal instrumentation of maxillary lateral incisors.     

A micro-computed tomography study of canal configuration of multiple-canalled mesiobuccal root of maxillary first molar

Objectives

Detailed information of complex anatomical configuration of mesiobuccal (MB) root is essential for successful endodontic treatment in maxillary first molars. The aims of this study were to investigate the configuration types present in multiple-canalled MB roots of maxillary first molars using micro-computed tomography (μCT) and to evaluate whether further modification to current configuration classifications are needed for in-depth morphology study of MB root canal system.

Materials and methods

One hundred and fifty-four extracted human maxillary first molar MB roots were scanned by μCT (Skyscan) and their canals were reconstructed by 3D modeling software. Root canal configurations were categorized according to the classifications proposed by Weine and Vertucci. Canal configurations that did not fit into both classifications were categorized as non-classifiable.

Results

One hundred and thirteen (73.4 %) MB roots had multiple canals. The most predominant canal configuration was Weine type III (two orifices and two foramens). Thirty-three (29.2 %) and 20 (17.7 %) MB roots had non-classifiable configuration types that could not be classified by the Weine and Vertucci classification, respectively. Three configurations (types 1–3, 2–3–2–3–2, and 2–3–4–3–2) were first reported in maxillary first molar MB roots.

Conclusions

The present μCT study provided an in-depth analysis of canal configurations of the MB roots of maxillary first molar and suggests that additional modification of current configuration classifications may be needed to more accurately reflect the morphology configurations of MB roots.

Clinical relevance

Clinicians should consider the complex canal configurations of the maxillary first molar MB roots during surgical or nonsurgical endodontic procedures.