Combined effects of calcium hydroxide and photobiomodulation therapy on apexogenesis of immature permanent teeth in dogs.

Treatment of high-risk traumatic immature teeth due to incomplete root development is challenging. Apexogenesis is currently the ideal treatment option that allows normal root development. The purpose of this study was to evaluate the apexogenesis process of immature permanent teeth of dogs when co-administered with calcium hydroxide and photobiomodulation therapy (PBMT). A total of 36 immature permanent anterior and premolar teeth were selected from three 4-6-month-old dogs of Iranian mixed generation. The teeth were categorized into two groups, calcium hydroxide with laser irradiation (CHL) and calcium hydroxide without laser irradiation (CH). All the selected teeth received calcium hydroxide pulpotomy. After restoring teeth with amalgam, the CHL group received gallium­aluminum-arsenide (GaAlAs) diode laser (810 nm, 4.2 J/cm2, 0.3 W, 9 s,CW) on apical one-third of both buccal and lingual roots. The irradiation was repeated every 48 h for fourteen days. Intravenous tetracycline was used to observe newly formed dentin in the first, third, seventh, and fourteenth days. The distance between tetracycline lines (DTL) was examined by Fluorescence microscopy. Generalized estimating equations (GEE) were used for data analysis. In all assessments, the mean DTL were greater in the CHL group. However, the two groups had no significant differences in the amount of deposited dentin between the first and third, third and seventh, and first and seventh lines. Meanwhile, there was a significant difference between the two groups in terms of the distances between lines 7 and 14, 1 and 14 and also 3 to 14 (P < .001). In other words, from the 7th day onwards, there was a significant difference between the two groups. Within the limitation of this study, the combination therapy of PBMT and pulpotomy with calcium hydroxide accelerated apexogenesis in immature permanent dogs' teeth.

Retrieval of extensive gutta-percha extruded into the maxillary sinus: use of 3-dimensional cone-beam computed tomography.

INTRODUCTION: Close proximity of the maxillary sinus to the roots of maxillary teeth can predispose to the inadvertent deposition of endodontic products into the maxillary sinus. One such material is thermoplasticized injectable gutta-percha, which has gained popularity of late. As a consequence of overfilling, some patients warrant surgical retrieval. METHODS: A case report of extreme overextension of gutta-percha within the maxillary sinus after endodontic retreatment on tooth #14 was provided. The distobuccal and palatal canals had been obturated with gutta-percha master cones and backfilled with thermoplasticized injectable warm gutta-percha. The mesiobuccal canal had only been filled with thermoplasticized injectable warm gutta-percha, the origin of the extrusion. Imagery with 3-dimensional cone-beam computed tomography was performed for localization of the gutta-percha. RESULTS: The patient underwent a Caldwell-Luc approach for removal of the extruded material. The gutta-percha was successfully removed intact, and the patient had an unremarkable postoperative course. However, the patient continues to have mild tenderness in the sinus region. CONCLUSIONS: The featured case exemplified the consequence of overinstrumentation and ensuing inadequate apical stop. In these situations, the obturation of a maxillary tooth with thermoplasticized injectable gutta-percha, without master cones, can potentially result in overfilling and deposition into the antrum. Use of 3-dimensional cone-beam computed tomography could enhance endodontic diagnosis, serve as an aid for visualization of foreign materials within the sinus and contiguous soft tissue structures, and improve clinical outcome.

The effect of nonsetting calcium hydroxide on root fracture and mechanical properties of radicular dentine: a systematic review.

The aim of this review was to identify and analyse all studies related to the effect of nonsetting calcium hydroxide [Ca(OH)(2)] on root fracture and various mechanical properties of radicular dentine. A PubMed search was conducted using the keywords 'calcium hydroxide' and 'dentistry' combined with MeSH terms 'tooth fractures' or 'mechanical phenomena' or 'compressive strength'. The search was expanded by including Embase and Web of Science databases, using the keywords 'calcium hydroxide' and 'root' and 'fracture'. The search was supplemented by checking the reference lists from each selected article. Each study had to meet the following criteria to be selected for review: (i) Inclusion of at least one experimental group with root or radicular dentine either filled with or exposed to nonsetting Ca(OH)(2); (ii) inclusion of at least one appropriate control group; and (iii) a minimum of five samples per experimental group. Only articles written in English were included. Of the 16 studies selected initially, 12 in vitro studies fulfilled the selection criteria for inclusion in the final review. No clinical studies that directly supported the correlation between Ca(OH)(2) intracanal dressing and root fracture were found in the literature. However, the majority of in vitro studies showed reduction in the mechanical properties of radicular dentine after exposure to Ca(OH)(2) for 5 weeks or longer. Conversely, the data were inconclusive regarding whether Ca(OH)(2) exposure for 1 month or less had a negative effect on the mechanical properties of radicular dentine.

Comparison between two thermoplastic root canal obturation techniques regarding extrusion of root canal filling--a retrospective in vivo study.

OBJECTIVES: The aim of this study was to compare two different thermoplastic techniques--a core-carrier technique (Thermafil) and warm vertical compaction--in terms of overextension of root canal filling in vivo. MATERIALS AND METHODS: Flaring of 88 teeth was conducted using Pro Files .04 as finishing files, and the teeth were obturated using Thermafil. Flaring of 74 teeth was performed using Pro Files .06 as finishing files, and the teeth were obturated using warm vertical compaction. RESULTS: Seventy (80 %) of the teeth obturated using Thermafil and 31 (42 %) teeth obturated using warm vertical compaction show extruded root canal filling. In contrast to Thermafil, there is a higher rate of extruded root canal filling of teeth with more than one root canal using warm vertical compaction. CONCLUSION: Thermafil demonstrated a higher rate of extruded root canal filling compared to warm vertical compaction. Warm vertical compaction is a more predictable method of filling compared to Thermafil. CLINICAL RELEVANCE: Root canal filling extrusion will cause irritation of the surrounding tissue and impair repair processes. In the present in vivo study, there was a higher rate of root canal filling extrusion using Thermafil compared to warm vertical compaction.

Quantification of fibrosis and mast cells in the tissue response of endodontic sealer irradiated by low-level laser therapy.

Low-level laser therapy (LLLT) accelerates tissue repair. Mast cells induce the proliferation of fibroblasts and the development of local fibrosis. The objective of this study was to quantify fibrosis rate and mast cells in connective tissue after endodontic sealer zinc oxide and eugenol (ZOE) was implanted and submitted to LLLT, immediately after implant and again 24 h later. Sixty mice were distributed into three groups: GI, GII, and GIII (n = 20). In GI, the tubes filled with Endofill were implanted in the animals and were not irradiated with LLLT. In GII, the tubes containing Endofill were implanted in the animals and then irradiated with red LLLT (InGaAIP) 685-nm wavelength, D = 72 J/Cm(2), E = 2 J, T = 58 s, P = 35 mW, and in GIII, the tubes with Endofill were implanted and irradiated with infrared LLLT (AsGaAl) 830-nm wavelength, D = 70 J/Cm(2), E = 2 J, T = 40 s, P = 50 mW. After 7 days and 30 days, the animals were killed. A series of 6-µm-thick sections were obtained and stained with Toluidine Blue and Picrosirius and analyzed under a standard light microscope using a polarized light filter for the quantification of fibrosis. The statistics were qualitative and quantitative with a significance of 5%. The irradiation with LLLT did not offer improvement in the fibrosis rate, however, it provided a significant decrease in the concentration of independent mast cells for the period studied.

Mineral trioxide aggregate: a comprehensive literature review--Part III: Clinical applications, drawbacks, and mechanism of action.

INTRODUCTION: Mineral trioxide aggregate (MTA) has been recommended for various uses in endodontics. Two previous publications provided a comprehensive list of articles from November 1993-September 2009 regarding the chemical and physical properties, sealing ability, antibacterial activity, leakage, and biocompatibility of MTA. The purpose of Part III of this literature review is to present a comprehensive list of articles regarding animal studies, clinical applications, drawbacks, and mechanism of action of MTA. METHODS: A review of the literature was performed by using electronic and hand-searching methods for the clinical applications of MTA in experimental animals and humans as well as its drawbacks and mechanism of action from November 1993-September 2009. RESULTS: MTA is a promising material for root-end filling, perforation repair, vital pulp therapy, and apical barrier formation for teeth with necrotic pulps and open apexes. Despite the presence of numerous case reports and case series regarding these applications, there are few designed research studies regarding clinical applications of this material. MTA has some known drawbacks such as a long setting time, high cost, and potential of discoloration. Hydroxyapatite crystals form over MTA when it comes in contact with tissue synthetic fluid. This can act as a nidus for the formation of calcified structures after the use of this material in endodontic treatments. CONCLUSIONS: On the basis of available information, it appears that MTA is the material of choice for some clinical applications. More clinical studies are needed to confirm its efficacy compared with other materials.

In vivo qualitative analysis of the biocompatibility of different cyanoacrylate-based adhesives.

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control)--distilled water, B--cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D--alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.

In vivo qualitative analysis of the biocompatibility of different cyanoacrylate-based adhesives

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control) - distilled water, B - cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D - alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.

Cross-Reactivity studies of gutta-percha, gutta-balata, and natural rubber latex (Hevea brasiliensis).

Gutta-percha and gutta-balata are derived from the Paliquium gutta and Mimusops globsa trees, respectively, that are in the same botanical family as the rubber tree Hevea brasiliensis. For this reason the potential for immunological cross-reactivity between the gutta-percha and gutta-balata used in endodontics and natural rubber latex (NRL) has been the subject of some controversy, because these products may be used in latex-allergic individuals. The objective of this study was to investigate the potential cross-reactivity between gutta-percha, gutta-balata, and NRL. Physiological extracts of seven commercially available gutta-percha products, raw gutta-percha, raw gutta-balata, and synthetic transpolyisoprene were each analyzed for cross-reactivity with NRL in a competitive radioallergosorbent test inhibition assay. No detectable cross-reactivity was observed with any of the raw or clinically used gutta-percha products. In contrast the raw gutta-balata released proteins that were cross-reactive with Hevea latex. We conclude that the absence of gutta-percha proteins that can react with Hevea latex-specific IgE antibody supports the minimal potential for commercially available gutta-percha to induce allergic symptoms in individuals sensitized to NRL. Because gutta-balata is sometimes added to commercial gutta-percha products caution should be exercised if products containing gutta-balata are used in endodontic care of latex-allergic individuals.

Biocompatibilidade de materiais endodônticos. Resposta do tecido subcutâneo de cobaias à resina poliuretana derivada do óleo de mamona - Parte 2 / Biocompatibility of endodontic materials subcutaneous tissue response of guinea-pig to polyurethane resin derived from castor bean oil - Part 2

A poliuretana derivada do óleo de mamona apresenta uma fórmula molecular que tem mostrado compatibilidade com os tecidos vivos. O propósito deste trabalho foi o de comparar esse polímero (Poliol) com quatro materais - AH26, Dentinol, Kerr Sealer, e Sealapex - segundo as normas da FDI e ADA/ANSI, com a finalidade da sua utilizaçäo como cimento de obturaçäo de canal. Todos os materiais foram manipulados de acordo com as instruçöes dos fabricantes. O método utilizado foi o de implante subcutâneo de tubos de Teflon em cobaias. (FDI, 1980; ADA/ANSI, 1982) Foram utilizadas 45 cobaias (+800gr cada), que receberam quatro implantes dorsais com o mesmo material (12 por período). A parede externa do tubo serviu como controle da técnica. Após 30, 60, e 90 dias, os animais foram mortos e os espécimes processados para exame histológico de rotina...