Pulse oximetry: a useful test for evaluating pulp vitality in traumatized teeth.

BACKGROUND AND AIM: Subjective pulp tests are not trustworthy, particularly in traumatized teeth, and may lead to inaccurate diagnosis. The use of an objective test such as pulse oximetry (PO) could be a more reliable method to properly evaluate pulp status in this condition. The aim of this study was to analyze the effectiveness of PO in determining pulp vitality in traumatized teeth based on oxygen saturation measurements (%SpO2 ). SUBJECTS AND METHODS: Fifty-nine permanent teeth that had undergone lateral luxation, and which were unresponsive to a cold spray test and were free from signs of necrosis, were selected and tested with PO at 7, 30 and 60 days after trauma. RESULTS: Fifty-nine teeth were tested. At 7 days after trauma, 8 teeth had low rates of oxygenation, compared to 10 at 30 and 60 days. Low rates were defined as a saturation reading ≤77%SpO2 . These teeth were assigned to the pulp necrosis (PN) group. The other 49 teeth were either considered to have healthy pulps (HP) (saturation ≥90%SpO2 ) or were assigned to a pulpitis (PP) group (saturation ≥78 to ≤89%SpO2 ). The 10 non-responsive teeth were followed up for 1 year and all exhibited indications for endodontic treatment. The other 49 teeth (HP or PP) began to show positive responses to the cold spray (after 3-9 months of follow up). No significant differences (P < 0.05) were detected between the three periods analyzed, but %SpO2 rates were significantly different (P < 0.01) between the groups (HP vs PP, HP vs PN and PP vs PN). CONCLUSIONS: PO can be extremely useful for the assessment of dental pulp status in traumatized teeth, particularly when these teeth do not show signs of PN and do not respond to cold tests.

Pulse oximetry as a dental pulp test: A scoping review to identify barriers hindering the use of oximeters in clinical practice.

Background and Objective: Although medical pulse oximeters are considered effective for endodontic diagnoses, the method remains uncommon in current dental practice. The aim of the present scoping review was to investigate clinical factors that exert a negative impact on the use of pulse oximeters in dental practice. Methods: This study followed the PRISMA-ScR guidelines and the protocol was prospectively registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/3GQCE). A comprehensive search of the MEDLINE (via PubMed), Cochrane Library, and Web of Science databases was performed in December 2022 for articles published in English or Spanish. All types of clinical studies were included, except comments, letters to the editor, and abstracts. Two independent investigators analyzed 45 full-text articles. Data extraction included general characteristics, oxygen saturation levels, and limiting factors/barriers to the use of oximeters as pulp testers. Results: The search of the databases yielded 1,300 records and 38 were included (quantitative data extraction was performed for 35 and three articles were systematic reviews). Publications were highest in number between 2016 and 2017, with an evident reduction occurring after 2021. The oxygen saturation level for sound/vital maxillary anterior teeth was 84.99% (overall mean). The main limiting factors/barriers were i) the difficulty in maintaining the two light-emitting diodes parallel during pulp tests, ii) infrared light diffraction by enamel/dentin/gingiva, and iii) the diversity of patient ages in studies. Conclusion: This scoping review encountered noteworthy findings associated with the impracticability of using medical pulse oximeters as dental pulp testers. The recent decrease in the frequency of published studies compared to approximately seven years ago may imply a negative trend in the use of the method.

Influence of rotary and reciprocating kinematics on the accuracy of an integrated apex locator.

We evaluated in vitro the influence of nickel-titanium instruments kinematics on the accuracy and variation of root canal working length measurements, performed with an integrated apex locator, at glide path and at the end of shaping. Forty-four mandibular incisors, included in an alginate model, were allocated at random to two groups: reciprocating and rotary. Working length was determined at glide path stage and at the end of shaping. Measurements given by the integrated apex locator were matched with visual measurements. The apex locator accuracy was based on inter-group comparison. The variation in working length was based on intra-group comparison. Kinematics influenced the accuracy of measurements only after shaping (p < 0.05), and not in the glide path (p > 0.05). Rotary had values closer to the visual measurements. Diminishing of measures occurred after shaping for reciprocating (p < 0.05); and at glide-path stage for rotary (p > 0.05). The integrated apex locator was more accurate with rotary kinematics.

Cytotoxicity and Bioactivity of Calcium Silicate-based Cements in a Culture of Stem Cells from the Apical Papilla.

Introduction: The present in vitro study evaluated the cytotoxicity and bioactivity of commonly-used calcium silicate-based cements in a culture of stem cells from the apical papilla (SCAPs). Materials and Methods: NeoMTA Plus (Avalon Biomed), BiodentineTM (Septodont) and MTA HP Repair (Angelus) cements were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and sulphorhodamine-B (SRB) viability assays. Cells were seeded (1*104 cells mL-1) in 96-well plates and exposed to 1:4 diluted extract in 24 h and 72 h. For the analysis of bioactivity, alkaline phosphatase (ALP) enzyme activity and Alizarin Red S (AZR) were assessed after 24 h of cell culture in 12-well plates (1*104 cells mL-1), where cells were exposed to 1:4 diluted extract on days 1 and 7. Minimum Essential Eagle's Medium alpha modification was used as control. ANOVA and Tukey's post hoc test were used to compare the different cements at each experimental time point. Results: No significant differences were found between the cements and the control specimens on MTT at 24 h and 72 h (P>0.05); however, the calcium silicate-based cement materials showed higher cell viability compared to the control group (P<0.05). In the 24-h SRB, NeoMTA Plus showed lower cell viability than BiodentineTM and MTA HP Repair (P<0.05), with all groups similar to the control group (P>0.05). Compared to 24-h results, only NeoMTA Plus presented increased cell viability at 72 h (P<0.05). ALP activity was similar across the materials at 1 day (P>0.05). ALP activity was higher for BiodentineTM when compared to NeoMTA Plus (P<0.05), nevertheless, it was similar to MTA HP Repair and control groups (P>0.05) at 7 days. At 1- and 7-day periods of AZR assay, BiodentineTM presented higher levels of mineralized nodule formation (P<0.05). Conclusion: All evaluated calcium silicate-based cements demonstrated cell viability and bioactivity, suggesting that these (bio)materials may be indicated for use in regenerative dentine-pulp complex procedures.

Cytocompatibility and cell proliferation evaluation of calcium phosphate-based root canal sealers.

OBJECTIVES: This study aimed to evaluate the cell viability and migration of Endosequence Bioceramic Root Canal Sealer (BC Sealer) compared to MTA Fillapex and AH Plus. MATERIALS AND METHODS: BC Sealer, MTA Fillapex, and AH Plus were placed in contact with culture medium to obtain sealers extracts in dilution 1:1, 1:2 and 1:4. 3T3 cells were plated and exposed to the extracts. Cell viability and migration were assessed by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and Scratch assay, respectively. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05). RESULTS: The MTT assay revealed greater cytotoxicity for AH Plus and MTA Fillapex at 1:1 dilution when compared to control (p < 0.05). At 1:2 and 1:4 dilutions, all sealers were similar to control (p > 0.05) and MTA Fillapex was more cytotoxic than BC Sealer (p < 0.05). Scratch assay demonstrated the continuous closure of the wound according to time. At 30 hours, the control group presented closure of the wound (p < 0.05). At 36 hours, only BC Sealer presented the closure when compared to AH Plus and MTA Fillapex (p < 0.05). At 42 hours, AH Plus and MTA Fillapex showed a wound healing (p > 0.05). CONCLUSIONS: All tested sealers demonstrated cell viability highlighting BC Sealer, which showed increased cell migration capacity suggesting that this sealer may achieve better tissue repair when compared to other tested sealers.

Reference values for pulp oxygen saturation as a diagnostic tool in endodontics: a systematic review and meta-analysis.

OBJECTIVES: This systematic review aimed to identify mean oxygen saturation values (SpO2) using pulse oximetry in permanent maxillary anterior teeth. MATERIALS AND METHODS: The MEDLINE, Scientific Electronic Library Online, Cochrane Central Register of Controlled Trials, EMBASE, and Literatura Latino Americana em Ciências da Saúde electronic databases were searched. Combinations and variations of "oximetry" AND "dental pulp test" were used as search terms. Studies reporting means and standard deviations of SpO2 values were included. Two reviewers independently extracted data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Heterogeneity was assessed using the I 2 statistic, and all analyses were performed using R software. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale. RESULTS: Of the 251 studies identified, 19 met the eligibility criteria and were included (total sample, 4,541 teeth). In the meta-analysis, the mean SpO2 values were 84.94% (95% confidence interval [CI], 84.85%-85.04%) for the central incisors, 89.29% (95% CI, 89.22%-89.35%) for the lateral incisors, and 89.20% (95% CI, 89.05%-89.34%) for the canines. The studies were predominantly low-quality due to the high risk of bias associated with the index test, unclear risk regarding patient selection, and concerns about outcome assessment. CONCLUSIONS: Although most studies were low-quality, the oxygen saturation levels in normal pulp could be established (minimum saturation, 77.52%). Despite the risk of bias of the included studies, the reference values reported herein are clinically relevant for assessments of changes in pulp status. TRIAL REGISTRATION: International Prospective Register of Systematic Reviews Identifier: CRD42018085598.

Interference of coronal enamel and dentin thickness and ambient light on pulse oximetry interpretation.

This study evaluated the interference of enamel and coronal dentin thickness and ambient light in pulse oximetry interpretation, using SaO2the human finger as a reference. Forty-two intact human permanent mandibular molars were sectioned mesiodistally in the central portion. Buccal and lingual dentin surfaces were drilled, and 4 mm, 3 mm and 2 mm enamel/dentin thicknesses were interposed between finger and device, after which SaO2 levels were measured by finger pulse oximetry. A reference device was designed to align pulse oximeter light-emitting diode, buccal surface of tooth, little finger, lingual surface of tooth and photodiode. Variables were described as means and standard deviation, and the confidence interval was reported. Repeated measures analysis of variance (ANOVA) was used to compare the groups, followed by Bonferroni correction. Student t test for paired samples was used to determine presence of ambient light (α = 0.05). Mean SaO2 level was lower at 4.0 ± 0.2 mm thickness, regardless of presence or absence of ambient light (92.7% and 89.3%). The other thicknesses yielded values of 95.5% and 94.5% at 3.0 ± 0.2 mm, and 96.4% and 96.0% at 2.0 ± 0.2 mm (p < 0.001). There were significant differences between SaO2 values at 4.0 ± 0.2 mm, 3.0 ± 0.2 mm and 2.0 ± 0.2 mm thicknesses, in the presence of ambient light. Mean SaO2 level in positive control was 96.3%, and mean pulse rate was 69.5 bpm in presence of ambient light; in the absence of light, these values were 96% and 70.5 bpm. Enamel and dentin thickness interfere with SaO2, regardless of presence or absence of ambient light. The lowest SaO2 levels were found for the thickest tooth samples.

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial.

OBJECTIVE: To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. MATERIALS AND METHODS: 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05). RESULTS: Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). CONCLUSIONS: Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

EVALUATION OF INTRAOPERATIVE PAIN OCCURRENCE AND NEED FOR SUPPLEMENTAL ANESTHESIA DURING EMERGENCY DENTAL CARE

Aims: This study aimed to evaluate the intraoperative pain (IOP) occurrence in situations of symptomatic irreversible pulpitis (SIP) and symptomatic apical periodontitis (SAP). Materials and Methods: Patients who sought emergency care presenting a diagnosis of SIP or SAP were included. IOP was measured with a Visual Analogue Scale (VAS) after five minutes of local anesthesia, during access to the pulp chamber, root canal exploration and at the end of procedures. In cases where pain was reported during treatment, supplementary anesthesia was performed. Pain scores were recorded and analyzed using a generalized estimating equation model with posthoc comparisons. Results: 56 patients were included. 35 had a diagnosis of SIP; and 21 a diagnosis of SAP. Mean preoperative pain scores for SAP and SIP were 6.69 (±1.54) and 6.39 (±1.48), respectively (p>0.05). In patients with SIP, significant differences were observed between: preoperative scores and other time points; scores after five minutes of local anesthesia and other time points; scores during pulp chamber access and at the end of procedures; and scores during root canal exploration and at the end of procedures (p<0.05). In patients with SAP, significant differences were observed between preoperative pain scores with all other time points (p<0.05). Chi-square test indicated an association between diagnosis and the need for supplementary anesthesia (p<0.05). Conclusions: In conclusion, there is a strong relationship between reduction of moderate/severe pain after application of local anesthesia. The need for supplemental anesthesia is significantly associated to the diagnosis of symptomatic irreversible pulpitis.

In vitro comparison of different reciprocating systems used during endodontic retreatment.

The present study evaluated the effectiveness of two reciprocating systems for the removal of root-filling material during endodontic retreatment. One hundred extracted mandibular premolars were prepared and root-filled with gutta-percha and sealer. Root fillings were removed with K-files according to the following techniques: Group A--hand instrumentation; Group B--Endo-Gripper system driven by compressed air; Group C--INTRAmatic 29CH + INTRA-LUX 3LD driven by compressed air; Group D--Endo-Gripper system driven by electric engine; Group E--INTRAmatic 29CH + INTRA-LUX 3LD driven by electric engine. The amount of filling debris on root canal walls was assessed radiographically and analysed using Auto CAD 2000 software. One-way anova and Duncan's test revealed statistically significant differences only in the middle third (P = 0.01); the best results being reached in group D. The apical third displayed the greatest amount of filling material debris, regardless of the technique used.

Computed tomography assessment of three techniques for removal of filling material.

In this study, computed tomography (CT) was used to assess three techniques for root canal filling removal. Seventy-five roots of extracted human lower incisors were filled with zinc oxide-eugenol sealer and gutta-percha and separated into three groups before gutta-percha removal (group 1, Gates Glidden burs + K-type hand instrumentation; group 2, K-type reciprocating instrumentation + NSK TEP E16R; group 3, ProTaper rotary instrumentation + NSK NAC E16R). Specimens were CT-scanned before and after filling removal. The mean rate of filling removal was 94.88%. Reciprocating instrumentation was the most effective and manual instrumentation associated with Gates Glidden burs was the least effective technique. Removal rate was significantly different for the three groups according to one-way anova (P = 0.049). The Tukey test showed a significant difference between groups 1 and 2 (P = 0.039) only. CT proved to be a reliable method for assessing root filling removal techniques.

Mandibular molar with five root canals.

The purpose of this study was to demonstrate the importance of knowledge of the internal anatomy of root canals for the success of endodontic treatment. Lack of knowledge of anatomic variations and their characteristics in different teeth has been pointed out as one of the main causes of endodontic therapy failure. In this report, the authors describe the endodontic treatment of a mandibular first molar with five root canals, evaluate the rate of occurrence of this number of canals, and discuss the importance of their identification and treatment.

Effect of At-Home Bleaching on Oxygen Saturation Levels in the Dental Pulp of Maxillary Central Incisors.

The present study assessed oxygen saturation (SaO2) levels before, during, and after at-home bleaching treatment in the pulps of healthy maxillary central incisors. SaO2 levels were measured in 136 healthy maxillary central incisors using a pulse oximeter. The bleaching protocol consisted of 10% carbamide peroxide gel placed in individual trays and used for four hours daily for 14 days. SaO2 levels were assessed before bleaching (T0), immediately after the first session (T1), on the 7th day of treatment (T2), on the 15th day (the day following the last session) (T3), and 30 days after completion of the bleaching protocol (T4). Data were statistically analyzed using generalized estimating equations (GEE), Student's t test (p<0.05) and Pearson's correlation. Mean pulp SaO2 levels were 85.1% at T0, 84.9% at T1, 84.7% at T2, 84.3% at T3, and 85.0% at T4. Gradual reductions in SaO2 levels were observed, with significant differences (p<0.001) during the course of home bleaching treatment. However, 30 days after the end of the bleaching protocol, SaO2 levels returned to baseline levels. Home bleaching caused a reversible transient decrease in SaO2 levels in the pulps.

ASSESSMENT OF TORSION RESISTANCE OF GLIDE PATH ROTARY INSTRUMENTS

NiTi endodontic instruments for glide path are the most susceptible to fractures inside the root canal, mainly as a result of high torsional stress. Objective: The present study investigated the resistance to torsion and angular deflection of instruments destined for the glide path: ProGlider #16.02; T-File #17.02 and the MK Life #16.02. Materials and methods: Thirty rotating NiTi glide path instruments (n=10) with 25mm lengths were selected. The torsion test was performed based on ISO 3630-01 (1992). Three millimeters from the tip of the instruments, it was attached to a small load cell by a lever arm connected to the torsion shaft. Torsional strength and angular deflection were evaluated. Fracture surfaces were examined by scanning electron microscopy with magnifications of 1000x and 5000x in the cross section, and 50x in the lateral section. Statistical analysis was performed using the Kruskal-Wallis H test, followed by the Down's post hoc test. Results: The ProGlider instrument showed greater torsional strength (p<0.05) compared to the T-File (p<0.05) and MK Life (p<0.05), respectively. However, the T-File showed greater angular deflection (p<0.05) than the other groups tested. Conclusion: It can be concluded that the ProGlider instrument presented greater torque for the fracture, while the T-File instrument presented greater angular deflection.

Canal transportation after root canal instrumentation: a comparative study with computed tomography.

This in vitro study used computed tomography (CT) to compare the occurrence of canal transportation in the apical third of mesiobuccal canals in maxillary molars instrumented with 3 techniques. Sixty teeth were assigned to 3 groups (n = 20), and the root canals were instrumented as follows: Group 1, hand instrumentation with K-files; Group 2, K-files coupled to an oscillatory system powered by an electric engine; Group 3, ProTaper NiTi rotary system powered by an electric engine. To compare the canal transportation produced by the different techniques, preinstrumentation and postinstrumentation 3-dimensional CT images were obtained from root cross-sections of the region located 3 mm short of the apical foramen of each root canal. The CT scans were exported to Adobe Photoshop software, and the initial and final images were superimposed to detect the root canal wall differences between them. Canal transportation was measured by the distance between the prepared canal center and the anatomic canal center. The manual technique produced lesser canal transportation (0.10 mm) than the oscillatory and rotary techniques (0.37 and 0.22 mm, respectively); this difference was statistically significant (P=.021). All studied techniques produced canal transportation.

In vitro comparative analysis of 2 mechanical techniques for removing gutta-percha during retreatment.

OBJECTIVE: To compare the capacity of a reciprocating system (Endo-Gripper) and a rotary system (Profile .04) for mechanical removal of root-filling material from curved root canals in vitro. MATERIALS AND METHODS: Eighty canals (40 mesiobuccal and 40 mesiolingual) from mandibular first molars were instrumented and had their roots filled. After 6 months, 3-dimensional images of the roots were obtained by computed tomography (CT), and the volume of root-filling mass was measured. Root fillings were removed by either the reciprocating system with K-type files or the rotary system with NiTi files. The volume of filling debris remaining after the removal procedures was assessed by CT. The data were analyzed statistically by analysis of variance. RESULTS: Neither system completely removed the root-filling material. No significant differences were observed between the reciprocating and rotary systems in terms of the volume of filling material left within the canals after mechanical instrumentation. The volume of filling debris remaining was significantly lower for mesiolingual canals than for mesiobuccal canals. CONCLUSIONS: Currently available mechanical systems are unable to completely remove filling material during retreatment. Use of the "threshold" function of the CT software allowed precise outlining of the remnants of filling material and calculation of its volume.

Apical Transportation, Centering Ratio, and Volume Increase after Manual, Rotary, and Reciprocating Instrumentation in Curved Root Canals: Analysis by Micro-computed Tomographic and Digital Subtraction Radiography.

INTRODUCTION: This study aimed to evaluate apical transportation (AT), centering ratio (CR), and volume increase (VI) produced after instrumentation of mesiobuccal canals of maxillary molars with hand files, rotary, and reciprocating instruments using micro-computed tomographic (micro-CT) imaging and to demonstrate the ability of digital subtraction radiography (DSR) to evaluate AT. METHODS: Forty-five canals were randomly assigned to either group K, manual K-files; PTN, ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland); or Rec, Reciproc (n = 15 for each group) for preparation. Master apical files were #25, X2 (#25/06), and R25 (#25/08), respectively. Micro-CT imaging was used to measure AT (mm) and CR (mm) at 3 different locations (1, 4, and 7 mm from the apex). VI (mm3) was measured for each root third and for the whole canal. DSR (mesiodistal and buccolingual projections) was used to measure AT at 1 mm from the apex. RESULTS: AT and CR values were statistically similar across the groups at 1, 4, and 7 mm. AT results obtained for the different locations were similar within each group; CR, in turn, showed statistically lower values at 1 mm. VI was statistically similar in all groups. Both DSR and micro-CT imaging showed that AT always occurred on the outside of canal curvature. The highest mean value obtained for AT was 0.215 mm. CONCLUSIONS: AT, CR, and VI were similar for the K, PTN, and Rec groups. AT results were clinically irrelevant. DSR was as effective as micro-CT imaging in AT analysis and could be considered as an alternative method for assessing this outcome.

NSK reciprocating handpiece: in vitro comparative analysis of dentinal removal during root canal preparation by different operators.

The purpose of this study was to assess dentin removal during root canal preparation by different operators using a NSK reciprocating handpiece. Eighty-four human single-rooted mandibular premolars were hand instrumented using Triple-Flex stainless-steel files (Kerr) up to #30, weighed in analytical balance and randomly assigned to 4 groups (n=21). All specimens were mechanically prepared at the working length with #35 to #45 Triple-Flex files (Kerr) coupled to a NSK (TEP-E10R, Nakanishi Inc.) reciprocating handpiece powered by an electric motor (Endo Plus; VK Driller). Groups 1 to 4 were prepared by a professor of Endodontics, an endodontist, a third-year dental student and a general dentist, respectively. Teeth were reweighed after root canal preparation. The difference between weights was calculated and the means of dentin removal in each group were analyzed statistically by ANOVA and Tukey's test at 5 % significance level. The greatest amount of dentin removal was found in group 4, followed by groups 2, 3 and 1. Group 4 differed statistically from the other groups regarding dentin removal means [p<0.001 (group 1); p=0.005 (group 2); and p=0.001 (group 3)]. No statistically significant difference was found between groups 1 and 2 (p=0.608), 1 and 3 (p=0.914) and 2 and 3 (p=0.938). In conclusion, although the group prepared by a general dentist differed statistically from the other groups in terms of amount of dentin removal, this difference was clinically irrelevant. The NSK reciprocating handpiece powered by an electric engine was proved an effective auxiliary tool in root canal preparation, regardless of the operator's skills.

Tissue characterization following revascularization of immature dog teeth using different disinfection pastes.

Revascularization of immature teeth with necrotic pulps traditionally involves the use of triple antibiotic paste, which may sometimes lead to undesirable complications. The objective of this study was to assess tissue repair in immature dog teeth with apical periodontitis subjected to revascularization, comparing two different pastes used for root canal disinfection. Apical periodontitis was induced in 30 dog premolars. Teeth were randomly divided into three experimental groups: root canals filled with triple antibiotic paste (n = 10); root canals filled with 1% propolis paste (n = 10); and no medication (n = 10). An additional group (n = 10, no intervention) was used as control. After 7 months, the jaws were histologically evaluated for the following variables: newly formed mineralized tissue (present/absent); vital tissue in the canal space (absent/periodontal ligament-like/pulp-like); apical extension of root (present/absent); and severity of inflammatory process (absent/mild/moderate/severe). There were no statistically significant differences among the experimental groups in new mineralized tissue formation and apical root development. The formation of vital tissue in the canal space, in turn, was statistically different between the triple paste and propolis groups: vital tissues were present in all revascularized teeth disinfected with propolis paste (100%), compared to 71% of those disinfected with the triple paste. Severity of inflammatory process was different between the triple paste and no medication groups. The new tissues formed onto canal walls and in the root canal space showed characteristics of cementum and periodontal ligament, respectively. Propolis may have some advantages over the triple paste for the revascularization of immature teeth.

Histologic Analysis of the Influence of a Gelatin-based Scaffold in the Repair of Immature Dog Teeth Subjected to Regenerative Endodontic Treatment.

INTRODUCTION: Regenerative endodontic treatment is a new and promising approach to manage immature teeth with necrotic pulps and apical periodontitis. The use of scaffolds is essential to treatment success, but many materials are difficult to acquire and have a high cost. This study assessed tissue repair in immature dog teeth with necrotic pulps and apical periodontitis after using a gelatin-based scaffold (Gelfoam; Pharmacia & Upjohn Co, Kalamazoo, MI). METHODS: Apical periodontitis was induced in 20 immature dog teeth. After disinfection with triple antibiotic paste for 2 weeks, canals were irrigated, dried, and filled with a blood clot alone (10 teeth) or combined with Gelfoam (10 teeth). Another 10 teeth were used as negative controls (no intervention). After 7 months, the dogs were euthanized. Histologic sections were stained with hematoxylin-eosin and analyzed in relation to tissue repair. Categoric data were analyzed using the Fisher exact test (P < .05), numeric data (histomorphometric analysis), and the Mann-Whitney U test. RESULTS: Histologic analysis revealed a higher percentage of roots with new cementumlike mineralized tissue and connective tissue inside the canal in the blood clot + Gelfoam group (P < .001). Histomorphometric analysis showed a higher area of mineralized tissue in the same group (P = .029). Apical extension of root and inflammation were similar between the experimental groups. The new tissue formed onto canal walls and in the root canal space showed characteristics of cementum and periodontal ligament, respectively. CONCLUSIONS: The use of a gelatin-based scaffold (Gelfoam) combined with a blood clot improved repair in immature dog teeth with apical periodontitis subjected to regenerative endodontic treatment.