Frank C. Setzer

Outcome of endodontic surgery: a meta-analysis of the literature--part 1: Comparison of traditional root-end surgery and endodontic microsurgery.

INTRODUCTION The aim of this study was to investigate the outcome of root-end surgery. The specific outcome of traditional root-end surgery (TRS) versus endodontic microsurgery (EMS) and the probability of success for comparison of the 2 techniques were determined by means of meta-analysis and systematic review of the literature. METHODS An intensive search of the literature was conducted to identify longitudinal studies evaluating the outcome of root-end surgery. Three electronic databases (Medline, Embase, and PubMed) were searched to identify human studies from 1966 to October 2009 in 5 different languages (English, French, German, Italian, and Spanish). Relevant articles and review papers were searched for cross-references. Five pertinent journals (Journal of Endodontics, International Endodontic Journal, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics, Journal of Oral and Maxillofacial Surgery, International Journal of Oral and Maxillofacial Surgery) were individually searched back to 1975. Three independent reviewers (S.S., M.K., and F.S.) assessed the abstracts of all articles that were found according to predefined inclusion and exclusion criteria. Relevant articles were acquired in full-text form, and raw data were extracted independently by each reviewer. Qualifying papers were assigned to group TRS or group EMS. Weighted pooled success rates and relative risk assessment between TRS and EMS were calculated. A comparison between the groups was made by using a random effects model. RESULTS Ninety-eight articles were identified and obtained for final analysis. In total, 21 studies qualified (12 for TRS [n = 925] and 9 for EMS [n = 699]) according to the inclusion and exclusion criteria. Weighted pooled success rates calculated from extracted raw data showed 59% positive outcome for TRS (95% confidence interval, 0.55-0.6308) and 94% for EMS (95% confidence interval, 0.8889-0.9816). This difference was statistically significant (P < .0005). The relative risk ratio showed that the probability of success for EMS was 1.58 times the probability of success for TRS. CONCLUSIONS The use of microsurgical techniques is superior in achieving predictably high success rates for root-end surgery when compared with traditional techniques.

Outcome of Endodontic Surgery: A Meta-analysis of the Literature—Part 2: Comparison of Endodontic Microsurgical Techniques with and without the Use of Higher Magnification

INTRODUCTION The aim of this study was to investigate the outcome of root-end surgery. It identifies the effect of the surgical operating microscope or the endoscope on the prognosis of endodontic surgery. The specific outcomes of contemporary root-end surgery techniques with microinstruments but only loupes or no visualization aids (contemporary root-end surgery [CRS]) were compared with endodontic microsurgery using the same instruments and materials but with high-power magnification as provided by the surgical operating microscope or the endoscope (endodontic microsurgery [EMS]). The probabilities of success for a comparison of the 2 techniques were determined by means of a meta-analysis and systematic review of the literature. The influence of the tooth type on the outcome was investigated. METHODS A comprehensive literature search for longitudinal studies on the outcome of root-end surgery was conducted. Three electronic databases (ie, Medline, Embase, and PubMed) were searched to identify human studies from 1966 up to October 2009 in 5 different languages (ie, English, French, German, Italian, and Spanish). Review articles and relevant articles were searched for cross-references. In addition, 5 dental and medical journals (ie, Journal of Endodontics, International Endodontic Journal, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics, Journal of Oral and Maxillofacial Surgery, and International Journal of Oral and Maxillofacial Surgery) dating back to 1975 were hand searched. Following predefined inclusion and exclusion criteria, all articles were screened by 3 independent reviewers (S.B.S., M.R.K., and F.C.S.). Relevant articles were obtained in full-text form, and raw data were extracted independently by each reviewer. After agreement among the reviewers, articles that qualified were assigned to group CRS. Articles belonging to group EMS had already been obtained for part 1 of this meta-analysis. Weighted pooled success rates and a relative risk assessment between CRS and EMS overall as well as for molars, premolars, and anteriors were calculated. A random-effects model was used for a comparison between the groups. RESULTS One hundred one articles were identified and obtained for final analysis. In total, 14 studies qualified according to the inclusion and exclusion criteria, 2 being represented in both groups (7 for CRS [n = 610] and 9 for EMS [n = 699]). Weighted pooled success rates calculated from extracted raw data showed an 88% positive outcome for CRS (95% confidence interval, 0.8455-0.9164) and 94% for EMS (95% confidence interval, 0.8889-0.9816). This difference was statistically significant (P < .0005). Relative risk ratio analysis showed that the probability of success for EMS was 1.07 times the probability of success for CRS. Seven studies provided information on the individual tooth type (4 for CRS [n = 457] and 3 for EMS [n = 222]). The difference in probability of success between the groups was statistically significant for molars (n = 193, P = .011). No significant difference was found for the premolar or anterior group (premolar [n = 169], P = .404; anterior [n = 277], P = .715). CONCLUSIONS The probability for success for EMS proved to be significantly greater than the probability for success for CRS, providing best available evidence on the influence of high-power magnification rendered by the dental operating microscope or the endoscope. Large-scale randomized clinical trials for statistically valid conclusions for current endodontic questions are needed to make informed decisions for clinical practice.

Postoperative Pain after the Application of Two Different Irrigation Devices in a Prospective Randomized Clinical Trial

INTRODUCTION The extrusion of irrigation solutions beyond the apical constriction may result in postoperative pain. Sodium hypochlorite can cause severe tissue irritation and necrosis outside the root canal system if extruded into the periodontal ligament (PDL) space. Different delivery techniques were discussed to reduce this potential risk. The aim of this study was to compare the postoperative level of pain after root canal therapy using either endodontic needle irrigation or a negative apical pressure device. MATERIAL AND METHODS In a prospective randomized clinical trial, 110 asymptomatic single-rooted anterior and premolar teeth were treated endodontically with two different irrigation techniques. The teeth were randomly assigned to two groups. In the MP group (n = 55), procedures were performed using an endodontic irrigating syringe (Max-i-Probe; Dentsply Rinn, Elgin, IL). The EV group (n = 55) used an irrigation device based on negative apical pressure (EndoVac; Discus Dental, Culver City, CA). Postoperatively, the patients were prescribed ibuprofen 200 mg to take every 8 hours if required. Pain levels were assessed by an analog scale questionnaire after 4, 24, and 48 hours. The amount of ibuprofen taken was recorded at the same time intervals. RESULTS During the 0- to 4-, 4- to 24-, and 24- to 48-hour intervals after treatment, the pain experience with the negative apical pressure device was significantly lower than when using the needle irrigation (p < 0.0001 [4, 24, 48 hours]). Between 0 and 4 and 4 and 24 hours, the intake of analgesics was significantly lower in the group treated by the negative apical pressure device (p < 0.0001 [0-4 hours], p = 0.001 [4-24 hours]). The difference for the 24- to 48-hour period was not statistically different (p = 0.08). The Pearson correlation coefficient revealed a strongly positive and significant relationship for the MP group (r = 0.851, p < 0.001) and the EV group (r = 0.596, p < 0.0001) between pain intensity and the amount of analgesics. CONCLUSION The outcome of this investigation indicates that the use of a negative apical pressure irrigation device can result in a significant reduction of postoperative pain levels in comparison to conventional needle irrigation.

Periapical Bone Regeneration after Endodontic Microsurgery with Three Different Root-end Filling Materials: Amalgam, SuperEBA, and Mineral Trioxide Aggregate

INTRODUCTION The purpose of this study was to determine the bone regeneration potential to different root-end filling materials by evaluating the distance between the materials and newly regenerated bone after root-end surgery. MATERIAL AND METHODS Periapical lesions were induced in premolars and molars of five female beagle dogs. The teeth were treated endodontically after the development of the lesions. After 1 week, the teeth underwent root-end surgery using modern microsurgical techniques. Three different root-end filing materials were used: amalgam (Tytin; Kerr Mfg Co, Romulus, MI), SuperEBA (Bosworth, Skokie, IL), and mineral trioxide aggregates (MTA; Dentsply, York, PA). After 4 months, the dogs were sacrificed, and the jaws were prepared for histological sectioning. The distances from the root-end filling materials to the regenerated bone were determined by the evaluation of microradiographic images of the sections with imaging software (Sigma Scan/Image; Jandel Scientific Software, San Rafael, CA). The results were statistically analyzed with analysis of variance using Sigma Stat software (Jandel Scientific Software, San Rafael, CA). RESULTS The mean distances from the newly regenerated bone were 0.397 +/- 0.278 mm in the MTA group, 0.756 +/- 0.581 mm in the SuperEBA group, and 1.290 +/- 0.386 mm in the amalgam group. There was a statistically significant difference between the amalgam and MTA groups (p < 0.05). No significant differences existed for amalgam versus SuperEBA and SuperEBA versus MTA. CONCLUSION MTA showed the most favorable periapical tissue response. The distance from MTA to the regenerated bone was similar to the normal average periodontal ligament thickness in dogs.

Comparison of apical transportation between two rotary file systems and two hybrid rotary instrumentation sequences.

INTRODUCTION The aim of this study was to evaluate apical transportation of 2 rotary file systems and 2 hybrid rotary instrumentation sequences. METHODS One hundred twenty-four mesiobuccal canals of extracted molars were instrumented by 4 nickel-titanium rotary sequences. Group PF (n = 32) was instrumented with ProFile Series 29 to size #6 (#36/.06) at working length (WL). Group ES (n = 28) used EndoSequence to #35/.06. Group PFLS (n = 32) used ProFile Series 29 followed by LightSpeed in a hybrid technique to a final size #50. Group PTLS (n = 32) was instrumented with ProTaper and additional enlargement with LightSpeed to #50 in a hybrid technique. A double-digital radiographic technique was used to measure canal transportation at 0.5-5.0 mm from WL. Statistical analysis was carried out with one-way analysis of variance. RESULTS There was no statistically significant difference for apical transportation between the groups at any level from the WL (0.5 mm, P = .74; 1.0 mm, P = .09; 2.0 mm, P = .29; 3.0 mm, P = .65; 4.0 mm, P = .21; 5.0 mm, P = .12). CONCLUSIONS indicated that combining different file systems does not lead to increased levels of apical transportation. Hybrid instrumentation might be a valid alternative to achieve larger apical diameters without higher risk of procedural errors.

Failure of Fiber Posts after Cementation with Different Adhesives with or without Silanization Investigated by Pullout Tests and Scanning Electron Microscopy

INTRODUCTION The aim of the study was to test retentive forces of different adhesive systems after cementation of glass-fiber posts with or without prior silanization of the post by using a pullout test and scanning electron microscope (SEM) observation to detect the mode of failure. METHODS Fifty-six roots were randomly divided into 6 experimental and 2 control groups: ParaCore (PAR), Paracore + silane (PAR-SIL), RelyX Unicem (RXU), RelyX Unicem + silane (RXU-SIL), RelyX ARC (RXA), RelyX ARC + silane (RXA-SIL), negative control (NEG-CON), and positive control (POS-CON). ParaCore posts were placed in the experimental groups (each n = 8) by using an adhesive resin with or without prior silanization. NEG-CON received uncemented posts (n = 4); POS-CON received an active screw post with an adhesive (n = 4). All samples were subjected to a pullout test in a universal mechanical testing machine for pullout tests and SEM to assess the fiber posts and the roots after the tests. RESULTS Mean failure load values for each ground were PAR 247.4 ± 59.3 N, PAR-SIL 240.5 ± 68.8 N, RXU 102.3 ± 22.8 N, RXU-SIL 106.4 ± 19.8 N, RXA 119.8 ± 27.3 N, RXA-SIL 125.8 ± 28.3 N, NEG-CON 0 ± 0 N, and POS-CON 412.9 ± 27.4 N. There was a statistically significant difference between the 3 experimental adhesive systems (P < .001) and between each experimental group and NEG-CON and POS-CON (P < .05). PAR was significantly different from RXU and RXA (P < .05). No statistically significant differences existed between RXU and RXA and between the use of silanization or not. Representative samples for SEM showed cohesive failure as the principal fracture mode for PAR and mainly adhesive failure for RXU and RXA. CONCLUSIONS The results indicated that silanization of fiber posts does not make a difference to prevent dislocation of a post. Full-etching systems demonstrated significantly higher retentive forces than self-etching systems.

Influence of combined cyclic fatigue and torsional stress on the fracture point of nickel-titanium rotary instruments.

INTRODUCTION The combined influence of cyclic fatigue and torsional stress on rotary nickel-titanium instruments has been little investigated. The aim of this study was to determine possible differences in the fracture point of rotary nickel-titanium instruments depending on the application of cyclic fatigue only (CO) or in combination with torsional stress (CT). METHODS A novel custom-designed testing device was constructed. The device used a 2-pin design to test files under cyclic fatigue stress and allowed the additional application of defined torsional stress to the lateral aspect of the file by cutting into a dentin block. Files were tested dynamically at an amplitude of 2 mm at 0.0625 Hz using a programmable computer-controlled system. Three rotary NiTi systems were tested at 30° under CO or CT (with an added 1-Ncm torsional load): Revo-S (Micro-Mega, Besancon, France), Vortex (Dentsply, York, PA), and Profile (Dentsply) of tip sizes 25 and 35. For each file type, 10 new files 25 mm in length with a 0.04 taper size were tested. A total of 120 files were tested: 60 for CO and 60 for CT. The mean fragment length (MFL [in millimeters from the shaft to the fracture point]) was measured under 10× magnification with an electronic gauge to assess the location of the fracture. One-way analysis of variance, the Tukey Honestly Significant Differenct (HSD) test, and the Students t test for paired samples were used for statistical analysis. RESULTS All fractures, regardless if CO or CT was used, occurred within the area of the curvature. The addition of a torsional load (CT) resulted in a mean 1.09-mm statistically significant difference between CO and CT (P < .0001, CO MFL = 17.78 mm [standard deviation ± 1.08 mm, n = 60]; CT MFL = 16.69 mm [SD ± 0.54 mm, n = 60]), relocating the fracture point toward the area where torsional load was applied. There was a statistically significant difference between the 3 file systems when they were tested either in the CO mode (P < .01) or the CT mode (P < .05). Statistically significant differences also existed for both instrument sizes (ie, 25 [P < .01] and 35 [P < .0001]). CONCLUSIONS CT compared with CO resulted in statistically significantly different MFLs. All fractures remained within the area of the curvature, but with the addition of a torsional load, the location of the fracture moved in the direction of the additionally applied torsional stress. This suggests that stress was distributed from the area in which the torsional load was applied toward the area undergoing cyclic fatigue.

Pulp Vitality in Patients with Intraoral and Oropharyngeal Malignant Tumors Undergoing Radiation Therapy Assessed by Pulse Oximetry

INTRODUCTION The aim of this study was to evaluate pulp oxygenation levels (%SpO(2)) in patients with malignant intraoral and oropharyngeal tumors treated by radiotherapy (RT). METHODS Pulp oxygenation levels were measured by pulse oximetry. Twenty patients were selected, and two teeth of each participant (n = 40) were analyzed, regardless of the quadrant and the area irradiated, at four different time points: TP1, before RT; TP2, at the beginning of RT with radiation doses between 30 and 35 Gy; TP3, at the end of RT with radiation doses between 60 and 70 Gy; and TP4, 4 to 5 months after the beginning of cancer treatment. RESULTS Mean %SpO(2) at the different time points were 93% (TP1), 83% (TP2), 77% (TP3), and 85% (TP4). The Students t test showed statistically significant differences between TP1 and TP2 (P < .01), TP3 (P < .01), and TP4 (P < .01). TP3 was also statistically significantly different when compared with TP2 (P < .01) and TP4 (P < .01). No statistically significant difference could be observed between TP2 and TP4. CONCLUSIONS Because the mean %SpO(2) before RT was greater than during and after therapy and values obtained 4 to 5 months after the beginning of RT were close to the initiation of RT, pulp tissue may be able to regain normal blood flow after RT. If the changes in the microcirculation of the dental pulp were indeed transitory, preventive endodontic treatment or extraction in patients who are currently undergoing or recently received RT and who show negative signs of pulp sensitivity may not be necessary for pulpal reasons.

A Maxillary Central Incisor with Three Root Canals: A Case Report

Maxillary central incisors have been reported with 1, 2, and occasionally 3 root canals. The complete biomechanical instrumentation and obturation of the root canal system are mandatory to achieve endodontic success. Root canal systems with abnormal variations present a challenge in diagnosis and clinical management to the practitioner. This article presents a detailed case report of the endodontic treatment of a 3-canal maxillary incisor with an associated periodontal defect.

Conventional and Surgical Retreatment of Complex Periradicular Lesions With Periodontal Involvement

A periradicular pathosis with an associated periodontal breakdown creates a complex problem during endodontic therapy. In cases in which nonsurgical retreatment does not have a successful outcome, a surgical retreatment has to be taken into consideration. With the introduction of microsurgical techniques in endodontics, surgical treatment success has improved considerably. The surgical treatment of combined lesions, however, is still considered to have a less favorable prognosis. The presented cases illustrate successful treatments in which a periodontal breakdown and an endodontic breakdown were present.