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Introduction: Current pulp revascularization procedures in teeth with necrotic pulps and open apices have produced histologic evidence of connective tissue growth, cementum, and bone within the root canals of experimental animals. This study aims to investigate the effect of maintaining uninflamed residual apical pulp tissue on the histologic outcome of pulp-dentin complex regeneration after a revascularization procedure in immature ferret cuspid teeth., Methods: Twenty-eight cuspid teeth from 7 young male ferrets were used in this experiment. Seven teeth were reserved to serve as positive control samples without any treatment. In another 7 teeth, the pulp was completely extirpated (negative control), whereas the pulp of the remaining 14 teeth were removed to either 1-2 mm short of the apex (7 samples) or 2-4 mm short of the apex (7 samples). Blood clots were covered with mineral trioxide aggregate at the cementoenamel junction level of each tooth. Three months later, block sections were removed for histologic evaluations, and the data were statistically analyzed with the chi-square test (P < .05)., Results: All teeth with complete pulp extirpation showed the presence of bone inside the root canal. In contrast, the root canals for most teeth with pulp amputation 1-4 mm from the radiographic apex were filled with normal pulp, which extended coronally to the mineral trioxide aggregate, where hard tissue bridges had formed., Conclusions: Based on these results, we concluded that regeneration of the pulp-dentin complex is possible when the apical 1-4 mm of the apical pulp remains intact in immature teeth., (Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this systematic review was to determine whether soft tissue biotype at implant placement has an influence on crestal bone loss (CBL) at 1 year after implant loading., Material and Methods: Following electronic search in three databases (MEDLINE via OVID, EMBASE and The Cochrane Database) and hand search up to April 2015, two reviewers screened independently and in duplicate the references to identify randomized controlled trials, controlled clinical trials (CCTs) and prospective case series eligible for systematic review and meta-analysis. Cochrane Collaboration's tool was used for assessing risk of bias., Results: From 2944 citations, six studies (6 CCTs) met the inclusion criteria. Four of six individual studies that compared thin vs. thick biotype showed significantly higher CBL in thin biotype. Meta-analysis could only be performed with two studies and the differences did not reach significant level. None of the included studies was of low risk of bias., Conclusions: At present, there is insufficient evidence to answer the question on the differences in clinical outcome in terms of CBL between implants placed in sites with initial soft tissue thickness <2 mm and those with ≥2 mm. Further, well-designed controlled clinical studies are needed to analyze the effect of soft tissue thickness on the clinical outcomes of dental implants., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction: The aim of this in vivo study was to evaluate the influence of apical periodontitis (AP) on the accuracy of Dentaport ZX (J Morita, Kyoto, Japan), Raypex 5 (VDW, Munich, Germany), and i-Root (S-Denti, Seoul, Korea) electronic root canal length measurement devices (ERCLMDs)., Methods: Thirty-two single-rooted teeth scheduled for extraction, consisting of 16 teeth with AP and 16 teeth with normal periapex (NP), were selected. The access cavity was prepared, and the coronal portion of the canal was flared. The electronic working length (EWL) was determined by each ERCLMD according to each manufacturer's instructions. Each tooth was extracted, and the actual working length (AWL) was determined by inserting a size 15 K-file until the tip could be seen at a position tangential to the major foramen and then 0.5 mm was subtracted from the measurement. The distance from the file tip (EWL) to the point 0.5 mm coronal to the major foramen (AWL) was calculated. Data were analyzed using the nonparametric Fisher exact test and the chi-square test. Statistical significance was set at P < .05., Results: The accuracies of Dentaport ZX, Raypex 5, and i-Root within ± 0.5 mm in the AP group were 93.8%, 81.3%, and 75.0%; they were 93.3%, 86.7%, and 73.3% in the NP group, respectively. There were no significant differences between the accuracy of each device in the 2 groups (P > .05). Considering the 2 groups of AP and NP, there were no statistically significant differences in the accuracy of the ERCLMDs (P > .05)., Conclusions: The presence of AP did not influence the accuracy of ERCLMDs., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The purpose of this in vitro study was to evaluate and compare the efficacy and safety of different devices available for canal cleansing., Methods: The following systems were tested: passive ultrasonic irrigation, EndoVac (Discus Dental, Culver City, CA), and the irrigation ultrasonic needle (ProUltra PiezoFlow Irrigation Ultrasonic Needle; Dentsply Tulsa Dental Specialties, Tulsa, OK) used in both the injection mode (IUNI) and the aspiration mode (IUNA). In the control group, traditional irrigation with a syringe and side-vented needle was used. A resin model was used with 4 lateral canals (respectively at 2, 5, 8, and 11 mm from the apical foramen) filled with bovine pulp stained with fuchsin. The model also included a 2-mm chamber in communication with the apex, again filled with bovine pulp, which enabled the measurement of the extrusion of NaOCl beyond the apex., Results: With regard to efficacy, the most effective systems were found to be those using the ultrasonic needle, either in aspiration or injection modes; EndoVac was the least effective. Conversely, IUNI was found to bring the highest risk with regard to the extrusion of sodium hypochlorite beyond the apex. EndoVac was the safest but only by a slight margin compared with IUNA and passive ultrasonic irrigation., Conclusions: Based on this study, the system that best reconciles efficacy and safety appears to be IUNA., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background and Objective: The exact cause of orthodontic relapse is still unclear, although it is often suggested to be caused by periodontal collagen fibers. We hypothesize that long-lived collagen fibers in the periodontium cause relapse. The aim was to determine the half-life of periodontal collagen fibers around rat molars., Material and Methods: Thirty weanling rats were repeatedly injected with (3) H-proline, and autoradiography of histological sections was performed at 1, 4, 8, 15, 22, 29, 36, 57, 78 and 113 d after labeling. Grain densities determined in specific areas of the periodontium were used to calculate collagen half-life., Results: The half-life (t(½) ) was found to decrease from the supra-alveolar region to the apical periodontal ligament region. It was longer in the supra-alveolar region (1.39 ± 0.14 wk) compared with the deeper regions (p < 0.05). The t(½) of the upper periodontal ligament region (0.78 ± 0.20 wk) was longer than that of the inter-radicular periodontal ligament region (0.42 ± 0.07 wk, p < 0.05). The t(½) of the apical periodontal ligament region was 0.61 ± 0.15 wk., Conclusion: The data indicate that long-lived collagen fibers do not exist in the soft tissues of the periodontium, and are probably not responsible for relapse. The differences in collagen half-life might be caused by local variations in compressive strain induced by normal function., (© 2011 John Wiley & Sons A/S.)

Determination of the etiology of the patient's chief complaint and a correct diagnosis are paramount prior to a recommendation of endodontic therapy. Reproduction of the patient's chief complaint is critical. If the chief complaint cannot be reproduced, consider consultation with or referral to an endodontist or orofacial pain specialist. The diagnostic terminology presented in this update provides for a more accurate description and communication of the health or pathological conditions of both pulpal and apical tissues. This information is summarized in Table I.

Introduction: Clinical dentistry is in need of noninvasive and accurate diagnostic methods to better evaluate dental pathosis. The purpose of this work was to assess the feasibility of a recently developed magnetic resonance imaging (MRI) technique, called SWeep Imaging with Fourier Transform (SWIFT), to visualize dental tissues., Methods: Three in vitro teeth, representing a limited range of clinical conditions of interest, imaged using a 9.4T system with scanning times ranging from 100 seconds to 25 minutes. In vivo imaging of a subject was performed using a 4T system with a 10-minute scanning time. SWIFT images were compared with traditional two-dimensional radiographs, three-dimensional cone-beam computed tomography (CBCT) scanning, gradient-echo MRI technique, and histological sections., Results: A resolution of 100 μm was obtained from in vitro teeth. SWIFT also identified the presence and extent of dental caries and fine structures of the teeth, including cracks and accessory canals, which are not visible with existing clinical radiography techniques. Intraoral positioning of the radiofrequency coil produced initial images of multiple adjacent teeth at a resolution of 400 μm., Conclusions: SWIFT MRI offers simultaneous three-dimensional hard- and soft-tissue imaging of teeth without the use of ionizing radiation. Furthermore, it has the potential to image minute dental structures within clinically relevant scanning times. This technology has implications for endodontists because it offers a potential method to longitudinally evaluate teeth where pulp and root structures have been regenerated., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Optical microscopy and morphometric analysis were used in this study to evaluate, in vitro, the cleaning of the apical region in root canals with mild or moderate curvatures subjected to biomechanical preparation with a rotary system, as well as to assess the amount of extruded material to the periapical area. Lateral incisors (n = 32), 16 with curvature angles smaller or equal to 10º (GI) and 16 between 11º and 25º angles (GII) were submitted to Hero 642 rotary instrumentation with different surgical diameters: (A) 30.02 and (B) 45.02. Irrigation was performed at each change of instrument with 5 mL of ultrapure Milli-Q water and the extruded material through the apical foramen was collected. Root cross-sections were subjected to histological analysis by optical microscopy (×40) and the images were evaluated morphometrically using the Image Tool software. Quantification of the extruded material was performed by weighing after liquid evaporation. ANOVA showed no statistically significant differences (p>0.05) among the groups with respect to the procedures used to clean the apical region. Considering the amount of extruded material, the Tukey's HSD showed that canals with mild curvature prepared with the 45.02 surgical diameter showed significantly higher values (p<0.05) that those of the other groups, which were similar between themselves (p>0.05). In conclusion, the effect of cleaning the apical region did not differ in the groups, considering root curvature and the surgical diameter of instruments used for apical preparation. The amount of extruded material was greater in canals with mild curvature that were prepared with the 45.02 surgical instrument diameter.

Introduction: The purposes of this study were to determine bone density at various orthodontic implant sites and compare them according to depth and area (anterior and posterior, buccal and lingual, and maxilla and mandible)., Methods: Maxillofacial computed tomography scan data were obtained from 30 adults with normal occlusion. Bone density was recorded in Hounsfield units with simulated placement of miniscrews with the V-Implant program (CyberMed, Seoul, Korea). Bone density was measured to a depth of 6 mm at 1-mm intervals in 60 interdental areas (30 in the maxilla, 30 in the mandible), and mean bone density was calculated at each site., Results: Bone density tended to decrease with increasing depth, particularly in the posterior area. Mean bone density showed a progressive increase from posterior to anterior except for the mandibular buccal side, which had no significant differences. A comparison of the mean bone densities between the buccal and lingual sides in the mandible showed that the lingual side had higher values in the anterior area and vice versa in the posterior area. On the other hand, there were no distinct differences between the buccal and lingual sides in the maxilla. A comparison of the mean bone densities between the maxilla and the mandible showed higher values in the mandible, and these differences were more significant on the buccal side of the posterior., Conclusions: The differences in bone densities according to depth and area should be considered when selecting and placing miniscrew implants for orthodontic anchorage.

Self-guided slide/tape (ST) and web page (WP) instruction in normal radiographic anatomy of periapical and panoramic images is compared using objective test performance and subjective preference of freshman dental students. A class of seventy-four students was divided into a group studying anatomy in periapical images using WP and a group studying similar ST material. In a modified cross-over design the groups switched presentation technologies to learn anatomy in panoramic images. Students completed self-administered on-line quizzes covering WP materials and conventional quizzes for ST material. Students also completed a voluntary survey. Mean quiz performance identifying matched anatomic features in PA (n = 26) and panoramic images (n = 35) was excellent (96.9%) and not different between image types (p = 0.12) or presentation technologies (p = 0.81). Students preferred WP for accessibility, ease of use, freedom of navigation, and image quality (p < .01). Student comfort level with the quiz formats of the two technologies was not different (p = 0.11). Students experienced a higher rate of mechanical and logistical problems with ST than with WP technology. While 71 percent of the students preferred WP technology, this preference appears to be related to ease of use and facilitation of flexible learning styles rather than improved didactic performance.

The precise and more detailed structural topography of the periapical area of mandibular bones is largely unknown. The author reports his observations and test results related to the above area with special emphasis on their implantological significance. The decrease in the number of the so called trajectorium perialveolare i.e. the fine, elastic, radially organised bone trabecula, constituting the processus alveolaris, leads to the decrease of the mandibular bone-mass and the disintegration of the mandibular bone structure. The present publication aims to attract the stomatologists' attention to the importance and maintenance of the trajectorium perialveolare.

Endodontic needs of today's and tomorrow's growing older adult population present increasing challenges for dental care providers. Biologic and anatomic differences in the dental tissues between older and younger patients must be understood and considered in treatment planning and performance for appropriate endodontic procedures. These differences generally do not contraindicate treatment, which, when performed correctly, will be successful in the elderly patient.

Root canals of dog premolar teeth were instrumented beyond the apices and enlarged up to the size of a No. 40 or 80 file and filled with calcium hydroxide up to the foramen. Ninety days later the histologic data showed more favorable results with the root canals instrumented until file No. 80.

The root canals of twelve pairs of human incisors without hard tissue or periodontal disease were treated with either formocresol or glutaraldehyde. The periapical reactions were compared histologically after periods varying between 6 and 8 weeks. A formocresol dressing always resulted in irritation of the periapical tissues, whereas little or no irritation was found after treatment with glutaraldehyde. It can be concluded that, after a vital pulpectomy, treatment of root canals with glutaraldehyde is faster than, as efficient as, and less irritating than treatment with formocresol.

Healing after periapical surgery was studied clinically and radiologically in 108 patients in whom apicoectomy had been performed on 174 teeth. Histologic diagnosis was used to determine healing results; teeth with periapical granuloma tend to heal less successfully than teeth showing inflammation or cysts. Postoperative treatment played an important role in the healing process. In making a prognosis one must include preoperative status (including periodontal status), operating method, and postoperative treatment. The age of the patient also has some influence on healing.

Past studies dealing with the vascular supply to surgically mobilized dentoalveolar segments have mentioned occasional encounters with vital root transection and have noted varying degrees of pulpal response to this insult. The purpose of this investigation was to observe the pulpal and periapical responses of monkey dental tissues to intentional vital root transection over a 1-year postoperative period. Four adult Macaca mulatta monkeys were used in this study. All roots were surgically transected within the apical third with a bur. Maxillary and mandibular quadrants for 1, 2, 3, 4, 6, 12, 24, and 52 weeks following surgery were obtained after the animals were killed by perfusion of the left ventricle. The tissue blocks were prepared by routine histologic methods. The results demonstrated a disruption of the normal pulpal architecture, with initial pulpal degeneration and subsequent early replacement by the periodontal ligament tissue. A cellular cemental lining of the root canal occurred in all specimens. The periodontal ligament-like tissue continued to deposit cementum, resulting in almost total obliteration of the root canal and pulp chamber and leaving an intact but much reduced blood supply to the pulp chamber containing periodontal tissues.

The periapical tissues of adult teeth of monkeys were examined histologically after root canal treatment with calcium hydroxide. Healing, as evidenced by complete apical closure with a hard tissue bridge and an inflammation-free periodontal ligament, occurred more frequently where canals were instrumented 1 mm short of the apex. Overinstrumented canals exhibited a significantly decreased incidence of apical closure.

Vital maxillary canines of mature cats were intentionally instrumented through the foramen with No. 50 K-files. Dentin chips were packed into the apical opening in one tooth of each animal. In the contralateral tooth a dentin plug was not formed. Both root canals were then filled with gutta-percha. The animals were sacrificed at 3, 5, and 8 months. The results showed quicker healing characterized by minimal inflammation and cementum deposition in the specimens where dentin fillings were packed.

Root canals of dog premolar teeth were negotiated and overfilled with calcium hydroxide paste. After 30 days, half of the treated teeth were refilled up to the apical limit. Root canals not filled were considered as the control group. Ninety days after the first treatment, histologic analysis showed more favorable results in the refilled root canals. The overfilling elicits calcium hydroxide resorption and the ingrowth of periapical connective tissue into the root canal.

Forty-five abscessed human mandibular primary molars with bifurcation radiolucency were subjected to a two-stage formocresol treatment of the pulp chamber. On the first appointment, an elliptical patch of buccal mucosa was removed. Bony defects varied from 2 mm. to more than 4 mm. in diameter. Periapical radiographs were used to record changes in bone development. Punch biopsy specimens were taken from the bifurcation area of some subjects from 2 weeks up to a year after surgical curettement. Biopsied tissue was studied by electron and light microscopy to examine wound healing of the bifurcation, revealing an early proliferation of fibroblasts with extracellular collagen fibers. Some of the fibroblasts exhibited an extensive network of rough endoplasmic reticulum, scattered free ribosomes, mitochondria, and other organelles which are normally observed in healthy fibroblasts. Histologic and clinical evaluation support the treatment tested for retention of previously abscessed primary molars.

Ten cats were immunized with subcutaneous injections of keyhole limpet hemocyanin (KLH). After it was determined that the experimental animals had developed circulating antibodies to KLH, challenge doses of KLH were administered via the root canal system. The radiographic and histologic findings suggest that antigen-antibody complex reactions can occur in periapical tissues of teeth, and that they can play a role in the pathogenesis of periapical lesions. In contrast, no radiographic and histologic changes were noted in non-immunized cats.

To test the tissue compatibility of silicone rubber when it is used as a root canal filler, excess material was intentionally forced into the apical tissues in primates. The tissue response was one of general acceptance, with the usual response being fibrotic encapsulation. A low degree of inflammation was noted. Further studies are in progress.