Adham A. Azim

The Tennessee study: factors affecting treatment outcome and healing time following nonsurgical root canal treatment

AIM To determine factors that may influence treatment outcome and healing time following root canal treatment. METHODOLOGY Root filled and restored teeth by pre-doctoral students were included in this study. Teeth/roots were followed-up regularly, and treatment outcome was evaluated at every follow-up appointment (healed, healing, uncertain or unsatisfactory). Host (age, immune condition, pulp/periapical diagnosis, tooth/root type, location and anatomy) and treatment factors (master apical file size, apical extension, voids and density of root filling) were recorded from patient dental records. Univariate, bivariate and multivariate analyses were performed to determine the impact of the factors on treatment outcomes and healing times. RESULTS A total of 422 roots from 291 teeth met the inclusion criteria with a mean follow-up period of 2 years. The preoperative pulp condition, procedural errors during treatment, apical extension and density of root fillings significantly affected the treatment outcome. The average time required for a periapical lesion to heal was 11.78 months. The healing time increased in patients with compromised healing, patients older than 40 years, roots with Weine type II root canal systems, root canal systems prepared to a master apical file size <35, and roots with overextended fillings (P < 0.1). CONCLUSION Multiple host and treatment factors affected the healing time and outcome of root canal treatment. Follow-up protocols should consider these factors before concluding the treatment outcome: patients age, immune condition, as well as roots with overextended fillings, root canal systems with smaller apical preparations (size <35) or roots with complex canal systems. Intervention may be recommended if the treatment quality was inadequate or if patients became symptomatic.

Prevalence of Middle Mesial Canals in Mandibular Molars after Guided Troughing under High Magnification: An In Vivo Investigation

INTRODUCTION A limited number of in vivo studies have discussed the prevalence of middle mesial canals in root canal systems of mandibular molars. The reported results have varied between 1% and 25%, with no detailed description of the depth and direction of troughing needed to identify such small canal orifices. The objective of the present study was to determine (1) the prevalence of a middle mesial canal before and after troughing by using a standardized troughing technique, (2) the pathway of the middle mesial canal in relation to the mesiobuccal (MB) and mesiolingual (ML) canals, and (3) its correlation with the patients age. METHODS Ninety-one mandibular molars from 87 patients were included in this study. The patients age and tooth number were recorded. After access cavity preparation, a standardized troughing technique was performed between MB and ML canals to search for a middle mesial canal by using a dental operating microscope. If a middle mesial canal was located, it was recorded as separate or as joining the MB or the ML canals. Results were statistically analyzed by using Z test and logistic regression. RESULTS A middle mesial canal was found in 42 of 91 mandibular molars (46.2%). Six middle mesial canals were located after conventional access preparation (6.6%). The other 36 were located after standardized troughing (39.6%). The results were statistically significant (P < .001). There was a higher tendency to locate the middle mesial canal in second molars (60%) versus first molars (37.5%). Younger patients had a significantly higher incidence of a middle mesial canal (P = .004). CONCLUSIONS The middle mesial canal was present in 46.2% of mandibular molars. High magnification, troughing, and patients age appeared to be determining factors in accessing the middle mesial canal.

Management of longstanding furcation perforation using a novel approach.

INTRODUCTION Iatrogenic furcation perforation may occur during the access preparation of the endodontic treatment. This may lead to periodontal defects and subsequent tooth loss. In this case report, we presented a new approach that may help salvage cases with a longstanding furcation involvement and substantial bone loss resulting from perforation. METHODS A mandibular molar case that had a furcation perforation and longstanding furcation bone loss with a probing depth of 10 mm in the buccal furcation area. We applied a novel approach, which used both nonsurgical and surgical interventions. We first reaccessed the tooth to reseal the perforation site with MTA followed by a newly designed surgical approach including the use of a stent, a reverse submarginal flap, Emdogain (Straumann USA, Andover, MA), guided bone regeneration, and postoperative isolation of the surgical site. The post-treatment follow-ups with up to 19-month recall showed favorable results with significant bone regeneration at the furcation and the probing depth reduced to 4-5 mm. CONCLUSIONS Longstanding furcation perforations with periodontal involvement may be savable and have a better prognosis. This may require a modified flap design to access the defect, guided bone and periodontal regeneration, and postoperative isolation of the surgical defect.

XP Shaper, A Novel Adaptive Core Rotary Instrument: Micro–computed Tomographic Analysis of Its Shaping Abilities

Introduction The aim of this study was to investigate the shaping abilities of the XP Shaper (FKG, La Chaux‐de‐Fonds, Switzerland) and compare the findings with Vortex Blue (Dentsply Tulsa Dental Specialties, Tulsa, OK) using micro–computed tomographic imaging. Methods Twenty matched, extracted, mandibular, central incisors with a single, oval canal were scanned preoperatively at 25‐&mgr;m resolution and postoperatively after instrumentation with either Vortex Blue in a crown‐down manner up to size 30.04 or XP Shaper. The percent of untouched walls, changes in canal volume and surface area, the amount of dentin removed, debris remaining in the canal, and the preparation taper were determined. The total time required for instrumentation using each technique was calculated in seconds. Statistical analysis was used to compare between both groups using repeated measures multivariate analysis of variance with Bonferroni correction for post hoc comparison and independent sample t tests. Results The XP Shaper significantly increased the canal volume (F = 77.948, P < .001), surface area (F = 5.543, P = .030), and amount of dentin removed (F = 10.044, P = .001) and had significantly less untouched walls (38.6% ± 8.1%) compared with VB (58.8% ± 8.5%). There was less debris at all levels of the canal in the XP Shaper group. Results were almost significant (P = .059). The XP Shaper was also significantly faster in completing the mechanical preparation of the root canal space by almost 1 minute (t = 6.216, P < .001). Conclusions The XP Shaper can expand beyond its core size to adapt to the anatomy of the root canal space. The XP Shaper can prepare and touch more canal walls in oval‐shaped canals compared with Vortex Blue. However, the final preparation taper will vary according to the anatomy of the treated tooth. HighlightsThe XP Shaper represents a new generation of rotary files that can expand beyond its core size.The XP Shaper can touch more canal walls than Vortex Blue in oval‐shaped canals.Mechanical preparation of the canal can be completed with the XP shaper in a shorter duration compared with Vortex Blue.The final preparation taper of the XP Shaper will vary from one case to the other depending on the original canal anatomy.

Acquisition of Anatomic Parameters Concerning Molar Pulp Chamber Landmarks Using Cone-beam Computed Tomography

INTRODUCTION Cone-beam computed tomographic (CBCT) imaging is a valuable tool for endodontic therapy. The aim of this study was to verify whether clinical use of CBCT imaging can accurately acquire parameters concerning molar pulp chamber landmarks, which are important data to help start a successful access cavity and avoid iatrogenic furcation perforations. METHODS Seventy CBCT images were used to measure 118 maxillary and 104 mandibular molars. The following vertical distances were measured: from the cusp tip/central fossa to the pulp chamber floor, to the pulp chamber ceiling, and to furcation; from the pulp chamber ceiling to furcation; from the pulp chamber floor to furcation; and the pulp chamber height. Measurements were read to the nearest 0.05 mm. RESULTS The measurements were as follows: the pulp chamber floor to furcation (maxillary molar: 1.97 ± 0.58 [mean ± standard deviation, mm], mandibular molar: 2.24 ± 0.47), the pulp chamber ceiling to furcation (maxillary molar: 4.09 ± 0.68, mandibular molar: 3.78 ± 0.70), the central fossa to furcation (maxillary molar: 8.78 ± 0.79, mandibular molar: 8.53 ± 0.65), the central fossa to the pulp chamber floor (maxillary molar: 6.81 ± 0.83, mandibular molar: 6.29 ± 0.65), the central fossa to the pulp chamber ceiling (maxillary molar: 4.69 ± 0.59, mandibular molar: 4.75 ± 0.56); and pulp chamber height (maxillary molar: 2.12 ± 0.81, mandibular molar: 1.53 ± 0.68). Measurements showing the least standard deviation were the central fossa to furcation and the central fossa to the pulp chamber floor. CONCLUSIONS CBCT imaging may be used for precise clinical acquisition of the pulp chamber landmark measurements for molars thereby facilitating successful access cavity.

Variations of Palatal Canal Morphology in Maxillary Molars: A Case Series and Literature Review

Abstract A series of challenging cases with unusual canal anatomy in the palatal roots of maxillary first and second molars is presented. A review of the literature was done to elucidate the prevalence of anatomic variations in the palatal canal of maxillary first and second molars. An uncertain or indefinite radiographic appearance of the palatal canal, or eccentric deviation of the master cone or previous root canal filling was considered an indication of a bifurcated palatal canal. Five maxillary molars with a bifurcated palatal canal were identified. A MEDLINE database search was performed to identify studies on the palatal canal morphology of maxillary first and second molars. Data were categorized based on the methodology used in each study. The overall prevalence of anatomic variations in the palatal canal of maxillary first and second molars was less than 2%; however, anatomic variations occurred more frequently in certain ethnic groups, reaching up to 33% in maxillary first molars and up to 14% in maxillary second molars. This case series showed that even experienced endodontic clinicians can miss a bifurcated palatal canal if they are not aware of or overlook the hidden clues for these anatomic variations. The traditional assumption of an exclusively single‐canal anatomy in palatal canals of maxillary molars needs to be changed, even though it is the most prevalent anatomy. The overall low percentage of more than 1 palatal canal in maxillary molars is disturbingly misleading, because in certain ethnic groups this prevalence can be considerably higher. HighlightsThe case series showed that experienced endodontic clinicians can miss a bifurcated palatal canal if they are not aware of these anatomic variations.Although the overall prevalence of anatomic variations in the palatal canal of maxillary molars is low (<2%), it can reach up to 33% in maxillary first molars and up to 14% in maxillary second molars in certain ethnic groups.

Efficacy of different irrigant protocols and application systems on sealer penetration using a stepwise CLSM analysis

This study compared several irrigation protocols and application systems for sealer penetration into dentinal tubules. Single‐rooted‐human teeth were divided into 5 experimental groups (n = 15) and a control group (n = 5), according to final irrigation protocols: standard needle irrigation (SNI); Vibringe; Vibringe + NaviTip FX (Vibringe NFX); Endo Spray (ES); and passive‐ultrasonic‐irrigation (PUI). Following obturation of the root canals, the percentage of the sealer penetration was measured at different depths using stepwise CLSM analysis. The sealer penetration in the experimental groups was significantly higher than the control group at all levels (p < .05). No significant differences were observed between Vibringe and SNI or Vibringe NFX, ES, and PUI at all depths (p > .05). The Vibringe NFX, ES, and PUI groups allowed deeper sealer penetration than SNI at 100, 250, and 500 μm levels (p < .05). The irrigant activation, the needle design, and the application form (syringe or spray) may impact the quality of the seal that is achieved with root canal filling.

Effect of Instrumentation Techniques and Preparation Taper on Apical Extrusion of Bacteria

Introduction The aim of this in vitro study was to evaluate the effects of different root canal instrumentation techniques and preparation tapers on the amount of apically extruded bacteria. Methods The root canals of 98 extracted human mandibular incisors were contaminated with Enterococcus faecalis suspension. After incubation at 37°C for 24 hours, the root canals were instrumented with K3 rotary files in a crown‐down (CD) or full‐length linear instrumentation technique (FL) by using 3 different root canal tapers (0.02, 0.04, and 0.06). During instrumentation, apically extruded bacteria were collected into vials containing saline solution. The microbiological samples were taken from the vials and incubated in brain‐heart agar medium for 24 hours, and the numbers of colony‐forming units (CFUs) were determined. The obtained results were analyzed with t test and one‐way analysis of variance for the comparisons between the instrumentation techniques (CD and FL) and the preparation tapers (0.02, 0.04, and 0.06), respectively. Tukey honestly significant difference test was used for pairwise comparisons. Results The preparation taper had no effect on the number of CFUs when a FL instrumentation technique was used (P > .05). There was a statistically significant difference in the CFUs between FL and CD techniques when the preparation taper was 0.02 (P < .05). There was no statistically significant difference between the 0.04 and 0.06 preparation tapers in any of the instrumentation techniques (P > .05). Conclusions Using a 0.02 taper in a CD manner results in the least amount of bacterial extrusion. The instrumentation technique did not seem to affect the amount of bacterial extrusion when 0.04 and 0.06 taper instruments were used for cleaning and shaping the root canal space. HighlightsApical extrusion of intracanal bacteria occurs with all instrumentation techniques.CD and FL techniques showed similar bacterial extrusion regardless of taper.CD instrumentation with .02 files resulted in the lowest extrusion.

Comparison between Single-file Rotary Systems: Part 1—Efficiency, Effectiveness, and Adverse Effects in Endodontic Retreatment

Introduction: The aim of this study was to evaluate in vitro the performance of 3 single‐file systems: WaveOne Gold Primary (WOG; Dentsply Sirona, Ballaigues, Switzerland), Hyflex EDM “one file” (EDM; Coltene/Whaledent, Alstatten, Switzerland), and XP Shaper (XP; FKG, La Chaux de Fonds, Switzerland), for nonsurgical endodontic retreatment on mandibular anterior teeth in regard to the amount of remaining filling material inside the canal, debris extrusion, and operation time. Methods: Sixty extracted standardized mandibular incisors presenting with a single oval canal were prepared to size 30.04 and obturated using warm vertical condensation. After 30 days (37°C, 100% humidity), teeth were randomly divided into 3 groups (n = 20) according to the file used for retreatment (WOG, EDM, or XP operated at 3000 rpm). During the retreatment procedures, preweighed vials were used to collect apically extruded debris, and the time required to remove the filling material was recorded in seconds. Cone‐beam computed tomographic scans were taken before and after the retreatment to determine the amount of remaining filling material inside the root canal space. Statistical analysis was performed using the Kruskal‐Wallis test, 1‐way analysis of variance, and the Pearson test at a 5% significance level. Results: There was a statistically significant difference among the groups regarding the instrumentation time (P < .05). XP was the fastest to remove gutta‐percha from the canals (40.54 ± 28.03 seconds) followed by EDM (55.77 ± 19.76 seconds) and WOG (105.92 ± 53.92 seconds). The percentage of remaining filling was significantly greater for WOG (26.65% ± 14.63%) (P < .05). No difference was found between EDM (13.51% ± 9.53%) and XP (8.60% ± 7.28%). No difference was found regarding the amount of extruded debris among the 3 groups (P > .05). Conclusions: XP was the most efficient in gutta‐percha removal from the canals when operated at a higher speed (3000 rpm) followed by EDM and WOG.