Apical microsurgery is accurate and minimally invasive, produces few complications, and has a success rate of more than 90%. However, due to the lack of awareness and understanding of apical microsurgery by dental general practitioners and even endodontists, many clinical problems remain to be overcome. The consensus has gathered well-known domestic experts to hold a series of special discussions and reached the consensus. This document specifies the indications, contraindications, preoperative preparations, operational procedures, complication prevention measures, and efficacy evaluation of apical microsurgery and is applicable to dentists who perform apical microsurgery after systematic training.
Microsurgery/standards* ; Humans ; Apicoectomy ; Contraindications, Procedure ; Tooth Apex/diagnostic imaging* ; Postoperative Complications/prevention & control* ; Consensus ; Treatment Outcome

OBJECTIVETo evaluate the orthodontic treatment outcome in patients with impacted maxillary central incisor in the mixed dentition.

METHODSNine patients, aged 8 to 11 years, with impacted maxillary central incisor were treated orthodontically. The cone-beam CT(CBCT) was taken before treatment, after treatment and one year out of retention to evaluate the root length, root canal wall thickness, width of the apical foramen, and degree of root bending, alveolar bone height and thickness. The crown-to-root ratio was calculated. The periodontal and endodontic conditions were evaluated. The parameters of the treated incisors and contralateral ones served as controls were compared.

RESULTSNine impacted teeth were treated successfully. Throughout the treatment, the root of impacted central incisor continued to develop and the alveolar bones also continued to develop and remodel. The condition of the alveolar bone of vertically impacted teeth was better than that of horizontally impacted ones. No periodontal pocket or pulp necrosis was found after treatment. Seven patients were examined one year after treatment. No significant difference was found in root length, palatal alveolar bone level and palatal alveolar bone thickness. The control group root length was (13.07±2.15) mm, the treatment group root length was (12.06±2.00) mm. No further alveolar bone loss, gingival recession and pulp necrosis were found. The control group labial and palatal alveolar bone levels were (0.90±0.62), (0.45±0.52) mm, labial and palatal alveolar bone thickness were (0.85±0.14), (1.21±0.41) mm. The treatment group labial and palatal alveolar bone levels were (2.18±1.59) mm, (0.57±0.71) mm, labial and palatal alveolar bone thickness were (0.48±0.29), (1.43±0.31) mm.

CONCLUSIONSOrthodontic therapy for impacted maxillary central incisor in the mixed dentition could promote root development and alveolar bone remodeling. Good periodontal and endodontic conditions were achieved.

Alveolar Bone Loss ; diagnostic imaging ; Child ; Cone-Beam Computed Tomography ; Dentition, Mixed ; Gingival Recession ; diagnostic imaging ; Humans ; Incisor ; diagnostic imaging ; Maxilla ; Orthodontics ; methods ; Tooth Apex ; diagnostic imaging ; Tooth Crown ; diagnostic imaging ; Tooth Root ; diagnostic imaging ; Tooth, Impacted ; diagnostic imaging ; therapy ; Treatment Outcome

This study evaluated, over a 4-month study period, the amount of apical root resorption occurring in maxillary central incisors following their retraction when employing either micro-implant or J-hook headgear anchorage. The prospective randomised clinical trial was conducted in Orthodontic Clinic, College of Stomatology, China from 2008-2009. Subjects are patients requiring fixed appliances on waiting list (n=20). In female Han Chinese patients aged from 16-26 years, standardized periapical radiographs from 10 randomly assigned patients with maxillary protrusions comprising the micro-implant group, and from 10 similar patients comprising the J-hook headgear group, were assessed for maxillary central incisor apical root resorption. Measurements before and after orthodontic therapy were also obtained from lateral cephalometric radiographs to calculate incisor horizontal retraction and vertical intrusion distances. Estimated retraction force vectors were calculated in horizontal and vertical directions for both treatment groups. Data analysis employed t-tests and the Pearson correlation test, with α=0.05 for statistical significance. The results showed that when compared with the J-hook group, significantly more apical root resorption shortening of the maxillary central incisors was observed in the micro-implant group (1.27 mm difference, 95% CI=0.70-1.84, P<0.001), which was associated with a significantly larger retraction distance (P=0.004) and a smaller vertical force component (P<0.0001). We are led to conclude that continuous activation of the nickel-titanium coil springs used in the micro-implant group resulted in significantly more apical root resorption shortening and maxillary central incisor retraction than when intermittent J-hook retraction was employed. The employment of continuous duration orthodontic forces presents a risk for increased apical root resorption that requires careful radiographic monitoring.
Adult ; Dental Implants ; Female ; Humans ; Incisor ; diagnostic imaging ; Maxilla ; diagnostic imaging ; Orthodontic Anchorage Procedures ; instrumentation ; methods ; Prospective Studies ; Radiography ; Root Resorption ; diagnostic imaging ; Tooth Apex ; diagnostic imaging ; Young Adult

Revascularization of immature necrotic teeth is a reliable treatment alternative to conventional apexogenesis or apexification. In case 1, a 12-year-old boy had his necrotic, immature mandibular left second premolar treated with a revascularization technique. At a24-month follow-up, periapical radiolucency had disappeared and thickening of the root wall was observed. In cases 2 and 3, a10-year-old boy had his necrotic, immature, bilateral mandibular second premolars treated with the same modality. At 48-month(in case 2) and 42-month (in case 3) follow-ups, loss of periapical radiolucencies and increases in the root wall thickness were also observed.
Apexification ; Bicuspid ; blood supply ; diagnostic imaging ; pathology ; surgery ; Child ; Dental Papilla ; blood supply ; drug effects ; pathology ; Dental Pulp ; blood supply ; drug effects ; pathology ; Dental Pulp Necrosis ; pathology ; therapy ; Follow-Up Studies ; Humans ; Male ; Mandible ; Neovascularization, Physiologic ; Radiography ; Regeneration ; Root Canal Irrigants ; therapeutic use ; Root Canal Therapy ; methods ; Tooth Apex ; blood supply ; diagnostic imaging ; Tooth, Deciduous ; blood supply ; pathology ; Treatment Outcome

OBJECTIVETo investigate the anatomic features of the root apexes of permanent three-rooted mandibular first molars.

METHODSA total of 122 permanent mandibular first molars of Han Chinese patients were collected. Twenty three-rooted and 25 two-rooted molars were scanned by micro-CT and then reconstructed three-dimensionally. The apical anatomy of the tooth models were analyzed in software Mimics 10.01. The long and short diameters of the apical constriction (AC), the distances between AC, apical foramen (AF) and apex were measured. One-way ANOVA and LSD-t tests were used to compare the groups in relation to AC diameter and the distances between the AC, AF and apex.

RESULTSThe AF of the mesiobuccal (MB) canals most frequently presented at the distal side of the apex (10 cases in three-rooted and 6 cases in two-rooted group), and of the mesiolingual (ML) canals, most often at the lingual side (8 cases in each group). The AF of the distobuccal (DB) roots were frequently located at the distolingual (DL) side (10 cases), and those of the DL roots and distal canals of two-rooted molars were most often at the buccal (7 cases) and distal (11 cases) sides, respectively. The percentage of the "classical" singular AC was 53% (80/151). The average long(D) and short(d) diameters of the AC of the DB canals were (0.32 ± 0.09) mm and (0.25 ± 0.05) mm, respectively, significantly larger than the DL canals [D = (0.27 ± 0.08) mm, d = (0.22 ± 0.06) mm, P < 0.05] and the ML canals [D = (0.24 ± 0.06) mm, d = (0.19 ± 0.06) mm, P < 0.01). In three-rooted group, the mean distances between AC and AF, AF and apex, and AC and apex were (0.67 ± 0.32), (0.49 ± 0.28) and (1.01 ± 0.34) mm, respectively.

CONCLUSIONSThe AF of three-rooted mandibular molars frequently deviate from the root apex, and the AC of the DB canal is wider than those of the other canals. The mean distances between AC, AF and the apex suggest that root canal therapy should terminate at 1 to 1.5 mm short of the radiographic apex.

Asian Continental Ancestry Group ; Humans ; Imaging, Three-Dimensional ; Molar ; anatomy & histology ; diagnostic imaging ; Tooth Apex ; anatomy & histology ; diagnostic imaging ; Tooth Root ; anatomy & histology ; diagnostic imaging ; X-Ray Microtomography ; methods

The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a total of 1 005 root canals) were examined. The anatomy risk factors assessed in each case included: tooth type (tooth location), root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type (tooth location), root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility (P<0.05). Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure.
Chi-Square Distribution ; Dental Pulp Calcification ; pathology ; Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Humans ; Logistic Models ; Odontometry ; Radiography ; Retreatment ; Risk Factors ; Root Canal Preparation ; instrumentation ; Tooth Apex ; Tooth Root ; anatomy & histology

AIMTo investigate the relationship between the positioning of the lower central incisor and physical morphology of the surrounding alveolar bone.

METHODOLOGYThirty-eight patients (18 males, 20 females), with mean age of 13.4 years, were included in this study. As part of orthodontic treatment planning the patients were required to take dental Cone-beam CT (CBCT) covering the region of lower incisors, the surrounding alveolar bone and the mandibular symphysis. The cephalometric parameters were designed and measured to indicate the inclination of lower central incisor and physical morphology of the adjacent alveolar bone. Computer-aided descriptive statistical analysis was performed using SPSS 15.0 software package for Windows. A correlation analysis and a linear regression analysis between the incisor inclination and the alveolar bone morphology were performed.

RESULTSSignificant positive correlations were found between the lower central incisor inclination and the morphological contour of the alveolar bone (P < 0.05). The lower central incisor root apex was closer to the lingual alveolar crest when it was buccally inclined.

CONCLUSIONThe morphology of the alveolar bone may be affected by incisal inclination.

Adolescent ; Alveolar Process ; diagnostic imaging ; pathology ; Cephalometry ; methods ; Chin ; diagnostic imaging ; pathology ; Cone-Beam Computed Tomography ; methods ; Female ; Humans ; Incisor ; diagnostic imaging ; pathology ; Male ; Mandible ; diagnostic imaging ; pathology ; Numerical Analysis, Computer-Assisted ; Patient Care Planning ; Software ; Tooth Apex ; diagnostic imaging ; pathology

OBJECTIVETo investigate the difference between digital periapical film and conventional film in the evaluation of tooth length and root resorption.

METHODSA standard for root resorption in vitro was developed based on 20 extracted upper central incisors. Digital periapical films and conventional periapical films were taken before and after the process of simulating root resorption at six different projection angles respectively. The tooth length and root resorption were measured on these films. The results were analyzed by paired-samples rank sum test.

RESULTSSignificant difference on tooth length measurement was found between two types of films on the same projection angle. No significant difference on the length of root resorption calculated on digital and conventional films was found.

CONCLUSIONSThe accuracy of the digital periapical film was greater than that of conventional periapical films. The conventional periapical film can still be used in the evaluation of root resorption.

Humans ; In Vitro Techniques ; Radiography, Dental, Digital ; Root Resorption ; diagnostic imaging ; Tooth Apex ; diagnostic imaging

OBJECTIVECurved canal preparation is much difficult in root canal therapy(RCT). Step back technique and routine technique are still regular methods in curved canal preparation. The purpose of this study was to introduce a new method reverse flaring technique, and to investigate its preparation efficiency in intermediate-curvature canals.

METHODS48 cases of lower first molars RCT were collected, which were first treated because of pulpitis or apical periodontitis in West China College of Stomatology, Sichuan University from Nov. 2001 to Aug. 2003, mesial canal curvature was intermediate (30 degrees-60 degrees), determined by Schineider method. Cases were divided into two groups, in reverse flaring technique group, canal preparation in 27 cases were finished by reverse flaring technique, 21 cases by step back technique as control. In working length determination and fitting master cone stages, cases in two groups which fit full working length were recorded, determined by radiograph, and analyzed by chi 2 test.

RESULTSIn working length determination stage, cases which fit full working length in reverse flaring technique group were significantly more than that of step back technique group (P < 0.05), in fitting master cone stage, cases which fit full working length in reverse flaring technique group were also significantly more than that of step back technique group(P < 0.05).

CONCLUSIONIn working length determination stage, cases which fit full working length in reverse flaring technique group were significantly more than that of step back technique group (P < 0.05), in fitting master cone stage, cases which fit full working length in reverse flaring technique group were also significantly more than that of step back technique group(P < 0.05).

Adult ; Dental Pulp Cavity ; anatomy & histology ; diagnostic imaging ; Female ; Humans ; Male ; Middle Aged ; Molar ; Periodontitis ; diagnostic imaging ; therapy ; Pulpitis ; diagnostic imaging ; therapy ; Radiography ; Root Canal Preparation ; instrumentation ; methods ; Root Canal Therapy ; Tooth Apex ; anatomy & histology ; diagnostic imaging