Interventions for treating traumatised ankylosed permanent front teeth.

BACKGROUND: Teeth that have suffered trauma can fuse to the surrounding bone in a process called dental ankylosis. Ankylosed permanent front teeth fail to erupt during facial growth and can become displaced, thus resulting in functional and aesthetic problems. Dental ankylosis is also associated with root resorption, which may eventually lead to the loss of affected teeth. Different interventions for the management of ankylosed permanent front teeth have been described, but it is unclear which are the most effective. OBJECTIVES: To evaluate the effectiveness of any intervention that can be used in the treatment of ankylosed permanent front teeth. SEARCH METHODS: The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 3 August 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 7), MEDLINE via OVID (1946 to 3 August 2015), EMBASE via OVID (1980 to 3 August 2015) and LILACS via BIREME (1982 to 3 August 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing any intervention for treating displaced ankylosed permanent front teeth in individuals of any age. Treatments could be compared with one another, with placebo or with no treatment. DATA COLLECTION AND ANALYSIS: Two independent review authors screened studies independently. Full papers were obtained for potentially relevant trials. Although no study was included, the authors had planned to extract data independently and to analyse the data according to the Cochrane Handbook for Systematic Reviews of Interventions. MAIN RESULTS: No randomised controlled trials that met the inclusion criteria were identified. AUTHORS' CONCLUSIONS: We were unable to identify any reports of randomised controlled trials regarding the efficacy of different treatment options for ankylosed permanent front teeth. The lack of high level evidence for the management of this health problem emphasises the need for well designed clinical trials on this topic, which conform to the CONSORT statement (www.consort-statement.org/).

Interventions for the management of external root resorption.

BACKGROUND: External root resorption is a pathological process, which tends to occur following a wide range of mechanical or chemical stimuli such as infection, pressure, trauma or orthodontic tooth movement. Although it is predominantly detected by radiography, in some cases root resorption may be identified by clinical symptoms such as pain, swelling and mobility of the tooth. Treatment alternatives are case-dependent and aim to address the cause of the resorption and aid the regeneration of the resorptive lesion. OBJECTIVES: To evaluate the effectiveness of any interventions that can be used in the management of external root resorption in permanent teeth. SEARCH METHODS: The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 14 October 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 9), MEDLINE via OVID (1946 to 14 October 2015) and EMBASE via OVID (1980 to 14 October 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: We included randomised controlled trials of permanent teeth with any type of external root resorption, which has been confirmed by clinical and radiological examination, comparing one type of intervention (root canal medications and canal filling, splinting or extraction of teeth or the surgical removal of any relevant pathology) with another, or with placebo or no treatment. DATA COLLECTION AND ANALYSIS: Two review authors screened search records independently. Full papers were obtained for potentially relevant trials. If data had been extracted, the statistical guidelines set out in the Cochrane Handbook would have been followed. MAIN RESULTS: No randomised controlled trials that met the inclusion criteria were identified. However, we identified one ongoing study that is potentially relevant to this review and will be assessed when it is published. AUTHORS' CONCLUSIONS: We were unable to identify any reports of randomised controlled trials regarding the efficacy of different interventions for the management of external root resorption. In view of the lack of reliable evidence on this topic, clinicians must decide on the most appropriate means of managing this condition according to their clinical experience with regard to patient-related factors. There is a need for well designed and conducted clinical trials on this topic, which conform to the CONSORT statement (www.consort-statement.org/).

Interventions for the management of external root resorption.

BACKGROUND: External root resorption is a pathological process which tends to occur following a wide range of mechanical or chemical stimuli such as infection, pressure, trauma or orthodontic tooth movement. Although it is predominantly detected by radiography, in some cases, root resorption may be identified by clinical symptoms i.e. pain, swelling and mobility of the tooth. Treatment alternatives are case-dependant and aim at the removal of the cause and the regeneration of the resorptive lesion. OBJECTIVES: To evaluate the effectiveness of any interventions that can be used in the management of external root resorption in permanent teeth. SEARCH STRATEGY: We searched the following databases in April 2010: The Cochrane Oral Health Group's Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 3); MEDLINE (via OVID) (1950 to April 2010); and EMBASE (via OVID) (1980 to April 2010). We also searched two regional bibliographic databases (IndMED and Iranmedex) and handsearched five Iranian dental journals using free text terms appropriate for this review. SELECTION CRITERIA: Randomised controlled trials comparing any type of intervention including root canal medications and canal filling, splinting or extraction of teeth or the surgical removal of any relevant pathology with each other, or placebo or no treatment applied to permanent teeth with any type of external root resorption which had been confirmed by clinical and radiological examination. DATA COLLECTION AND ANALYSIS: Two review authors conducted screening of studies in duplicate and independently. The Cochrane Collaboration statistical guidelines were to be followed. MAIN RESULTS: 66 trials were identified in our searches none of which matched our inclusion criteria. However, we identified one ongoing study which is potentially relevant to this review and will be assessed when it is published. AUTHORS' CONCLUSIONS: We were unable to identify any reports of randomised controlled trials regarding the efficacy of different interventions for the management of external root resorption. In view of the lack of any high level evidence on this topic, it is suggested that clinicians decide on the most appropriate means of managing this condition according to their clinical experience with regard to patient related factors. Future research should consist of robust clinical trials which conform to the CONSORT statement (www.consort-statement.org/).

Interventions for treating traumatised ankylosed permanent front teeth.

BACKGROUND: Teeth that have suffered trauma can fuse to the surrounding bone - the process referred to as dental ankylosis. Ankylosed permanent front teeth fail to erupt during facial growth and can become displaced, thus resulting in functional and aesthetic problems. Dental ankylosis is also associated with root resorption, which eventually leads to the loss of affected teeth. Different interventions for the management of ankylosed permanent front teeth have been described but it is unclear which are the most effective. OBJECTIVES: To assess the effects of treatment options for ankylosed permanent front teeth. SEARCH STRATEGY: We searched the following databases: Cochrane Oral Health Group Trials Register (to September 2009); Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 3); MEDLINE (1950 to September 2009); EMBASE (1980 to September 2009); and LILACS (1980 to September 2009). There were no language restrictions. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing any intervention for treating displaced ankylosed permanent front teeth in individuals of any age. DATA COLLECTION AND ANALYSIS: Two independent review authors screened studies in duplicate. Although no study was included, the authors had planned to extract data independently and to assess risk of bias following the Cochrane Collaboration methods. MAIN RESULTS: The search retrieved 77 references to studies. None matched the inclusion criteria and therefore were excluded. AUTHORS' CONCLUSIONS: There is no evidence from RCTs about the comparative effectiveness of the different treatment options for ankylosed permanent front teeth. The lack of high level evidence for the management of this health problem emphasises the need for well designed clinical trials.

Antibacterial agents in composite restorations for the prevention of dental caries.

BACKGROUND: Dental caries is a multifactorial disease in which the fermentation of food sugars by bacteria from the biofilm (dental plaque) leads to localised demineralisation of tooth surfaces, which may ultimately result in cavity formation. Resin composites are widely used in dentistry to restore teeth. These restorations can fail for a number of reasons, such as secondary caries, excessive wear, marginal degradation, tooth sensitivity, pulpal death, and restorative material fracture. Caries adjacent to restorations is one of the main causes for restoration replacement. The presence of antibacterials in both the filling material and the bonding systems would theoretically be able to affect the initiation and progression of caries adjacent to restorations. OBJECTIVES: To assess the effects of antibacterial agents incorporated into composite restorations for the prevention of dental caries. SEARCH STRATEGY: We searched the following databases in February 2009: the Cochrane Oral Health Group's Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 1); MEDLINE via OVID (1950 to February 2009) without filter; and EMBASE via OVID (1980 to February 2009) without filter. SELECTION CRITERIA: Randomised controlled clinical trials (RCTs) comparing resin composite restorations containing antibacterial agents with non-antibacterial containing composite restorations. DATA COLLECTION AND ANALYSIS: Two review authors conducted screening of studies in duplicate and independently, and although no eligible trials were identified, the two authors had planned to extract data independently and assess trial quality using standard Cochrane Collaboration methodologies. MAIN RESULTS: We retrieved 128 references to studies, none of which matched the inclusion criteria for this review and all of which were excluded. AUTHORS' CONCLUSIONS: We were unable to identify any randomised controlled trials on the effects of antibacterial agents incorporated into composite restorations for the prevention of dental caries. The absence of high level evidence for the effectiveness of this intervention emphasises the need for well designed, adequately powered, randomised controlled clinical trials.

Influence of different endodontic filling materials on root fracture susceptibility.

OBJECTIVE: To evaluate the influence of different endodontic materials on root fracture susceptibility. METHODS: Seventy-two mandibular incisors were sectioned 1mm below the cementoenamel junction to obtain roots of 12 mm length. Roots were submitted to chemomechanical preparation with the rotary instruments of Profile system. The obturation of root canals were performed with the following filling materials (n=12): GI, unfilled teeth (control); GII, Endofill+gutta-percha; GIII, Sealer 26+gutta-percha; GIV, AH Plus+gutta-percha; GV, Epiphany+gutta-percha; GVI, Epiphany+Resilon. After the sealers setting time, each root was embedded in acrylic resin. The specimens were then submitted to fracture resistance test using an Instron testing machine at 1mm/min. RESULTS: The ANOVA test showed no significant statistical difference (p>.05) among GI (162.16+/-41.4N), GII (168.46+/-37.5N), GIII (164.83+/-35.7N), GIV (168.29+/-38.7N), GV (172.36+/-20.6N) and GVI (193.11+/-42.8N). CONCLUSION: The core materials (gutta-percha or Resilon) combined with the tested endodontic sealers are not able to increase the root fracture resistance in canals submitted to chemomechanical preparation.

Impacts of Contracted Endodontic Cavities on Primary Root Canal Curvature Parameters in Mandibular Molars.

INTRODUCTION: The purpose of this study was to provide information regarding the debate on contracted endodontic cavities (CECs); their impacts on angle, location, and radius of the primary canal curvature (PCC) were assessed in type IV mesial root canals of mandibular molars at different stages of instrumentation. Impacts on treatment time were also assessed. METHODS: Twenty-four teeth were matched by radiographic and micro-computed tomographic criteria and accessed via CECs (CEC, n = 12) or nonextended traditional endodontic cavities (TECs, n = 12). PCC parameters were radiographically determined using a repositioning apparatus before glide path preparation (PI), after glide path preparation, and after final instrumentation (FI). Instrumentation was performed with PathFiles (13/.02, 16/.02; Dentsply Maillefer, Ballaigues, Switzerland) and ProFile Vortex files (Dentsply Tulsa Dental Specialties, Tulsa, OK) to size 30/.04 at the working length under copious irrigation. Changes in PCC were measured with ImageJ (National Institutes of Health, Bethesda, MD). The instrumentation time was recorded. Data were analyzed with 2-way repeated measures analysis of variance (α < .05) and Tukey honest significant difference tests. RESULTS: A significant (P < .001) decrease in the mean angle and increase in the mean radius were detected at each instrumentation stage for both CECs (angle: PI = 42.57°± 8.00°, FI = 32.61°± 5.17°; radius: PI = 6.48 ± 1.81 mm, FI = 10.55 ± 1.48 mm) and TECs (angle: PI = 38.80°± 7.15°, FI = 30.08°± 6.99°; radius: PI = 6.97 ± 2.31 mm, FI = 11.01 ± 2.20 mm). PCC location shifted apically (P < .001). Changes in PCC parameters did not differ significantly between CECs and TECs (P > .05). The treatment time was significantly (P < .0001) longer for CECs (83.17 ± 6.71 minutes) than for TECs (33.18 ± 9.20 minutes). CONCLUSIONS: Instrumentation of curved mesial canals reduced the severity and abruptness of PCC and shifted the PCC location apically similarly in mandibular molars with CECs and those with nonextended TECs. The extended treatment time with CEC merits consideration when debating CECs versus TECs.

Effect of Instrument Design and Access Outlines on the Removal of Root Canal Obturation Materials in Oval-shaped Canals.

INTRODUCTION: The aim of this study was to compare the effectiveness of TRUShape (TS) instruments with ProFile Vortex Blue (VB) instruments for the removal of obturation materials during retreatment of single-canal mandibular premolars performed through 2 access outlines. METHODS: Initial root canal treatment was completed through a contracted endodontic cavity (CEC) design. Canals were instrumented to an F2 ProTaper instrument, obturated with warm lateral condensation of gutta-percha with AH Plus sealer, and allowed to set for 30 days at 37°C and 100% humidity. For retreatment, specimens were divided into 2 groups (n = 24) on the basis of access outline, CEC or traditional endodontic cavity (TEC). Retreatment was initiated by using ProTaper Retreatment instruments (D1-D3). Specimens were then stratified, further divided (n = 12), and reinstrumented up to TS 40 .06v or 40 .06 VB. Irrigation was performed by using 8.25% NaOCl and QMix 2in1. Retreatment time was recorded. Teeth were sectioned and photographed, and the percentage of remaining obturation materials was measured. Data were analyzed with Kruskal-Wallis analysis of variance for two-factor tests (α < 0.05). RESULTS: The interaction between access design and instrument type showed that the combination of CEC-VB presented significantly higher amounts of remaining obturation materials on the canal surface when compared with TEC-VB, CEC-TS, and TEC-TS (P ≤ .05). None of these other combinations were different from each other (P > .05). Significantly more time was required for retreatment with CEC-TS (27.68 ± 1.4 minutes) than the other groups (P < .05). CONCLUSIONS: Neither retreatment protocol was able to completely eliminate all obturation materials from the root canal surface of mandibular premolars. However, in the presence of a CEC access design, using TS instruments removed more obturating material in single-rooted, oval-shaped canals.

Micro-Computed Tomographic Evaluation of the Influence of Root Canal System Landmarks on Access Outline Forms and Canal Curvatures in Mandibular Molars.

INTRODUCTION: This study investigated the influence of anatomic root canal system landmarks on access outline forms of mandibular molars and correlated these to the theoretical distance of orifice relocation and changes in canal primary curvature. METHODS: Thirty relatively calcified human mandibular molars were selected and examined by micro-computed tomographic imaging. Three-dimensional volume reconstructions were made, root canal system landmarks identified, and plotted: canal orifices, canal position at the furcation level, and pulp horn location. Each landmark was separately projected onto the occlusal surface, and 3 access designs were respectively proposed: (1) minimally invasive, (2) straight-line furcation, and (3) straight-line radicular. For each access design, the theoretical distance of orifice relocation and canal primary curvature were determined. Data were submitted to 2-way repeated measures analysis of variance (α < 0.05). RESULTS: The orifice relocation distance required to obtain each type of access outline was greater for radicular-based accesses (0.97 ± 0.32 mm) than for furcation accesses (0.52 ± 0.30 mm, P < .001) and resulted in a greater change in canal primary curvature (P < .001; 15.9° ± 4.6° and 9.4° ± 4.3°, respectively). The canal primary curvature for each access outline type was statistically different from each other (P < .0001), whereas the minimally invasive access showed the highest mean angle (40.1° ± 8.4°) followed by the straight-line furcation (30.7° ± 7.5°) and the straight-line radicular accesses (24.2° ± 8.4°). CONCLUSIONS: The use of different landmarks to establish access outline designs affected the primary angle of curvature in relatively calcified mandibular molars.

Effect of Er:YAG laser on adhesion of root canal sealers.

This in vitro study evaluated the effect of Er:YAG laser on adhesion to human dentin of Grossman, Endomethasone, N-Rickert, and Sealer 26 root canal sealers. The crowns of 40 human molars were cut on the occlusal side until a flat dentin surface was obtained. The teeth were divided into two groups: group 1, no laser application; and group 2, irradiation with Er:YAG laser (KaVo Key Laser 2; 11 mm focal distance, perpendicular to the dentin surface, 4 Hz frequency, 200 mJ energy, 62 J total energy and 313 pulses, 1-min application time, and 2.25 W power). Five samples were tested for each sealer and each group. An Instron universal testing machine was used for the adhesion test. Sealer 26 showed the best adhesion both with and without laser application (p < 0.01). Grossman and N-Rickert sealers had intermediate values, and Endomethasone had the worst adhesion. Application of Er:YAG laser did not alter the adhesion of Grossman, N-Rickert, or Endomethasone sealers. However, laser application increased the adhesion of Sealer 26. The epoxy resin-based root canal sealer (Sealer 26) adhered better to dentin prepared with and without Er:YAG laser than the zinc oxide/eugenol-based sealers (Endomethasone, N-Rickert, and Grossman).

Mechanism of action of sodium hypochlorite.

The choice of an irrigating solution for use in infected root canals requires previous knowledge of the microorganisms responsible for the infectious process as well as the properties of different irrigating solutions. Complex internal anatomy, host defenses and microorganism virulence are important factors in the treatment of teeth with asymptomatic apical periodontitis. Irrigating solutions must have expressive antimicrobial action and tissue dissolution capacity. Sodium hypochlorite is the most used irrigating solution in endodontics, because its mechanism of action causes biosynthetic alterations in cellular metabolism and phospholipid destruction, formation of chloramines that interfere in cellular metabolism, oxidative action with irreversible enzymatic inactivation in bacteria, and lipid and fatty acid degradation. The aim of this work is to discuss the mechanism of action of sodium hypochlorite based on its antimicrobial and physico-chemical properties.

Mechanism of action of sodium hypochlorite

The choice of an irrigating solution for use in infected root canals requires previous knowledge of the microorganisms responsible for the infectious process as well as the properties of different irrigating solutions. Complex internal anatomy, host defenses and microorganism virulence are important factors in the treatment of teeth with asymptomatic apical periodontitis. Irrigating solutions must have expressive antimicrobial action and tissue dissolution capacity. Sodium hypochlorite is the most used irrigating solution in endodontics, because its mechanism of action causes biosynthetic alterations in cellular metabolism and phospholipid destruction, formation of chloramines that interfere in cellular metabolism, oxidative action with irreversible enzymatic inactivation in bacteria, and lipid and fatty acid degradation. The aim of this work is to discuss the mechanism of action of sodium hypochlorite based on its antimicrobial and physico-chemical properties.