The purpose of this study was to evaluate the effects of apical constriction (AC) diameter, irrigant flow rate, and needle tip design on apical pressure (AP) during the root canal irrigation. Five extracted human mandibular premolars were instrumented up to #35 (0.06 taper) using nickel-titanium rotary instruments. AC was determined at 1 mm from the apical foramen. Three needles with different tip designs (notched, side-vented, and flat) were placed 3 mm from AC. APs were measured with varying flow rates of 0.05, 0.1, 0.2, and 0.3 mL/s. The AC diameter of the teeth was enlarged to #40 and #45 (0.06 taper) successively, and the aforementioned measurement procedure was repeated (n=5). When the other conditions were controlled, AP increased with decreasing AC diameter or increasing irrigant flow rate, and the AP of flat needle was the highest, followed by notched, and side-vented needle (p<0.05). The APs with 0.05 mL/s flow rate were lower than central venous pressure (5.88 mmHg) for all conditions. Under the conditions of the present study, flat needle is not recommended in narrow AC (0.35 mm), as the value of the AP with a flow rate of 0.05 mL/s is similar to the central venous pressure. However, in AC diameter of >0.35 mm, open-end (notched or flat) needles can be used to improve irrigant replacement in the apical portion using a flow rate of 0.05 mL/s.
Bicuspid ; Central Venous Pressure ; Constriction ; Dental Pulp Cavity ; Humans ; Needles ; Tooth ; Tooth Apex

OBJECTIVES: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). MATERIALS AND METHODS: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. RESULTS: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). CONCLUSIONS: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.
Bicuspid ; Dental Pulp Cavity ; Gutta-Percha ; Microscopy, Confocal ; Needles ; Rhodamines ; Tooth ; Tooth Apex

OBJECTIVES: Understanding the reason for an unsuccessful non-surgical endodontic treatment outcome, as well as the complex anatomy of the root canal system, is very important. This study examined the cross-sectional root canal structure of mandibular first molars confirmed to have failed non-surgical root canal treatment using digital images obtained during intentional replantation surgery, as well as the causative factors of the failed conventional endodontic treatments. MATERIALS AND METHODS: This study evaluated 115 mandibular first molars. Digital photographic images of the resected surface were taken at the apical 3 mm level and examined. The discolored dentin area around the root canal was investigated by measuring the total surface area, the treated areas as determined by the endodontic filling material, and the discolored dentin area. RESULTS: Forty 2-rooted teeth showed discolored root dentin in both the mesial and distal roots. Compared to the original filled area, significant expansion of root dentin discoloration was observed. Moreover, the mesial roots were significantly more discolored than the distal roots. Of the 115 molars, 92 had 2 roots. Among the mesial roots of the 2-rooted teeth, 95.7% of the roots had 2 canals and 79.4% had partial/complete isthmuses and/or accessory canals. CONCLUSIONS: Dentin discoloration that was not visible on periapical radiographs and cone-beam computed tomography was frequently found in mandibular first molars that failed endodontic treatment. The complex anatomy of the mesial roots of the mandibular first molars is another reason for the failure of conventional endodontic treatment.
Cone-Beam Computed Tomography ; Dental Pulp Cavity ; Dentin ; Molar* ; Replantation ; Retreatment* ; Tooth ; Tooth Apex ; Tooth Root ; Treatment Outcome

The aim of this study was to evaluate the factors affecting the healing of root fracture in immature permanent teeth and the prognosis of root fracture by statistically analyzing the relationship with the pulp and root healing.The radiographs of 51 root-fractured maxillary anterior permanent teeth were collected. In radiograph, locations of root fracture, apical foramen width and width of diastasis between the fragments were measured. The value of the studied parameters were compared by independent t-test and rogistic regression test.In conclusion, there was no difference in the prognosis of pulp healing according to the location of root fracture. However, root healing occurs well as the root fracture is located at the root apex (p < 0.05). Lastly, the smaller the width of diastasis between the fragments after reduction, the better the pulp healing was (p < 0.05).
Prognosis ; Tooth Apex ; Tooth

The purpose of this study was to analyze the ratio and rate of apical closure when inducing root growth of necrotic immature permanent teeth using alternative triple antibiotics. 24 permanent teeth in the treatment group and 27 premolars in the control group were retrospectively studied using periapical radiographs for more than 300 days after the first visit. The difference in the growth rate between the two groups was statistically compared using the Mann-Whitney test at a significance level of 0.05. There were no statistically significant differences between the two groups in the first month and during months 1 – 3, 3 – 6, and 6 – 12. After 12 months, the cumulative rate of decrease in the apical foramen width in the treatment group was 50.59% and that in the control group was 71.82%, which revealed a significant difference between the two groups. There were significant differences in the rates of decrease in the apical foramen width after 3, 6 months, and later period in the treatment group, respectively. The cumulative rate of increase in the root dentin area presented no statistically significant differences between the treatment group and control group during the entire period of examination.
Anti-Bacterial Agents ; Bicuspid ; Dentin ; Retrospective Studies ; Tooth Apex ; Tooth

OBJECTIVE: To evaluate the accuracy of optical coherence tomography (OCT) in detecting root cracks after root canal instrumentation using histological gold standard. METHODS: Twenty complete extracted human mandibular incisors that were free of caries, calculus, and root treatment were chosen and accessed coronally with a diamond bur, then mounted in resin blocks with alginate impression material using simulated periodontal ligaments, and the apex was exposed 3 mm. The teeth were stored in water at room temperature. Then the teeth were then instrumented to the major apical foramen (AF) at #30/0.09 using ProTaper Universal rotary nickel titanium system (Dentsply Maillefer, Ballaigues, Switzerland), irrigation with 1% sodium hypochlorite (NaOCl) by using a 26-gauge needle followed after each instrument. The apical root was scanned with 360° of rotation by Swept-Source Optical Coherence Tomography (SS-OCT) (wavelength: 1 310 nm, scan rate: 20 kHz, axial resolution: 16 μm) with driving device (stepper motor and lifting platform). The reconstruction images of axial planes 1, 2 and 3 mm from the apex were examined and the root cracks were blindly diagnosed by two observers. The horizontal section was performed at 1, 2 and 3 mm from the apex using low speed disc saw (Leica SP1600, Wetzlar, Germany). The presence of cracks was noted under an optical stereomicroscope (ZOOM-630E) with a cold light source using as gold standard to evaluate the accuracy of OCT in detecting root cracks after root canal instrumentation. RESULTS: After canals instrumentation with ProTaper Universal rotary nickel titanium system to #30/0.09, root cracks were detected in 9 of 20 teeth by histological examination. Crack lines were observed on 13 of 60 horizontal sections and cracks on 12 of the 13 sections were detected by OCT. No cracks were observed in the other 47 of the 60 horizontal sections,none of which was misdiagnosed by OCT. The overall accuracy rate for detection of root cracks with OCT was 0.983, the sensitivity was 0.923, the specificity was 1.000, the positive predictive value (PPV) was 1.000 and the negative predictive value (NPV) was 0.979. CONCLUSION OCT may be a promising nondestructive imaging method for diagnosing root canal cracks after canal instrumentation.
Bicuspid ; Dental Alloys ; Dental Pulp Cavity ; Dentin ; Humans ; Incisor ; Nickel ; Root Canal Preparation ; Root Canal Therapy ; Titanium ; Tomography, Optical Coherence ; Tooth Apex ; Tooth Root

OBJECTIVE: To compare the clinical treatment efficiency of platelet-rich fibrin (PRF) assisted revascularization and traditional revascularization in immature permanent teeth. METHODS: Eighteen non-vital immature permanent teeth of sixteen patients which were diagnosed as necrotic pulpitis with (or without) periapical inflammations were treated with PRF assisted revascularization. Twenty-two teeth non-vital immature permanent teeth of twenty patients which were diagnosed as necrotic pulpitis with (or without) periapical inflammations were treated with traditional revascularization. All the cases were accorded with inclusive criteria and were treated at Pediatric Dentistry of Peking University School and Hospital of Stomatology. The cases were followed up clinically and radiographically at regular intervals. Clinical examinations and periapical radiographs were recorded and analyzed. Clinical success rate was evaluated based on the clinical and radiographic findings. The changes of root length, dentine wall thickness and apical foramen width of the teeth from the two groups were measured and compared according to the preoperative and by recalling the periapical radiographs. RESULTS: The cases were followed up for 6-16 months. Clinically, totally 17 out of the 18 teeth in PRF group and 21 out of the 22 teeth in traditional group were asymptomatic with no sensitivity to percussion or palpation. PRF group tended to be more effective than traditional group clinically without significant differences (P=0.446). Radiographically, 15 out of the 18 teeth in PRF group and 15 out of the 22 teeth in traditional group displayed that the roots developed, showing that root length and dentine wall thickness increased and apical foramen closed. There was a marked difference in dentine wall thickening in PRF group in comparison with traditional group (P=0.039). However, the changes of root length increasing (P=0.411) and apical foramen width closure (P=0.737) were comparable in both groups. The result in electric pulp test (P=0.517), root canal calcification (P=0.324) and crown discolor (P=0.386) were also comparable in the two groups. CONCLUSION PRF assisted revascularization and traditional revascularization in non-vital immature permanent teeth which were diagnosed as necrotic pulpitis with (or without) periapical inflammations resulted in similar clinical outcomes. Both methods showed good prognosis. PRF revascularization seemed to have better effect on dentine wall thickening than traditional method.
Child ; Dental Pulp/blood supply* ; Dentition, Permanent ; Humans ; Platelet-Rich Fibrin ; Root Canal Therapy ; Tooth Apex

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

Stafne bone cyst (SBC) is a bone defect usually located in the posterior portion of the mandible or mandibular angle below the inferior alveolar nerve. The cases of SBC involving multiple anterior tooth apices and penetrating the mandibular bone are extremely rare. Here we present a case of an anterior-positioned SBC mimicking periapical cyst, which penetrated the mandibular bone, with a review of the differential diagnosis.
Bone Cysts* ; Diagnosis, Differential ; Mandible ; Mandibular Nerve ; Radicular Cyst* ; Tooth Apex

PURPOSE: This study aimed to investigate the clinical anatomy of lower premolar roots in a Spanish population by using cone-beam computed tomography (CBCT), correlating findings with patient gender and tooth type. MATERIALS AND METHODS: Using 70 CBCT images, we evaluated 126 healthy, untreated, well-developed lower premolars. The number and morphology of roots and root canals, and the foramina number were assessed. Results for gender and tooth type were compared using the chi-squared and ANOVA tests. RESULTS: The average length of teeth and roots was significantly higher in men (p=0.00). All 126 premolars had a single root. One canal was found in 83.3% of the premolars, with no gender or tooth type differences; Vertucci configuration types I and V were the most prevalent. The first premolars showed significantly greater variability than the second premolars (p=0.03). A single apical foramen was found in 89.7% of the premolars, with no differences by tooth type. Women had a significantly higher prevalence of two apical foramina than men (p=0.04). Some degree of curvature was observed in 65% of the premolars, with no differences by gender or tooth type. A root angle of more than 20degrees was found in 12.98% of the premolars, without any differences by gender or tooth. CONCLUSION: All premolars were single-rooted. One canal had the most prevalent morphology. More variability in canal anatomy was found in the first premolars. Curvatures greater than 20degrees were found at less than 5 mm from the apex.
Anatomy, Regional ; Bicuspid* ; Cone-Beam Computed Tomography* ; Dental Pulp Cavity ; Female ; Humans ; Male ; Mandible ; Prevalence ; Tooth ; Tooth Apex