OBJECTIVE: To study the effect of various intracanal materials on the accuracy of oral maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of vertical root fracture (VRF). METHODS: A total of twenty-four structurally intact single root canal dried and isolated teeth extracted for orthodontic treatment or periodontal disease were collected. The teeth were decrowned along the cemento-enamel junction (CEJ) and then used as samples for the study after conventional root canal preparation and post preparation. The 24 samples were divided into two groups with 12 samples in each group. Group A was the control group (no VRF group). According to intracanal materials, they were divided into five subgroups: blank group, fiber post group, gutta-percha point group, titanium post group and gold-palladium post group. Group B was the experimental group (VRF group), and subgroups were grouped as above. The VRF model was prepared by a unified method in the VRF group: the root was completely fractured in the buccolingual direction with a custom root canal nail and then cemented and reset. The control group was not subjected to the simulation of VRF. Titanium post and gold-palladium post were made according to the individuality of the root canal preparation, and the tightness of the post to the root canal wall was confirmed by X-ray radiograph. Then all the samples were scanned by CBCT in the isolate swine mandibular alveolar sockets. The diagnostic accuracy was statistically analyzed via blind interpretation by experienced endodontic specialists and oral and maxillofacial medical imaging specialists. RESULTS: The accuracy of the diagnosis of VRF in the blank group, fiber post group, gutta-percha point group, titanium post group, and gold-palladium post group in CBCT was 95.83%, 91.67%, 87.50%, 79.17%, and 45.83%, respectively. Compared with the blank group, the differences were not statistically significant in the fiber post group (P>0.999), the gutta-percha point group (P=0.500) and the titanium post group (P=0.125). The lowest diagnostic accuracy of VRF was found in the gold-palladium post group, and the difference was statistically significant compared with all other groups (P < 0.001). CONCLUSION Various intracanal materials have different degrees of influence on the diagnostic accuracy of VRF diagnosis in CBCT. The influence of fiber post, gutta-percha point and titanium post was small, while the influence of gold-palladium post was significant.
Animals ; Cone-Beam Computed Tomography/methods* ; Gold ; Gutta-Percha ; Palladium ; Swine ; Titanium ; Tooth Fractures/diagnostic imaging* ; Tooth Root/injuries* ; Reproducibility of Results

Post-and-core crown is one of the most common forms of restoration of tooth after root canal therapy (RCT). Infection control is the core objective of RCT, which is usually well realized by endodontists. However, many prosthodontists often neglect the infection control of the tooth and the maintenance of the curative effect of RCT during the process of post-and-core crown, which may lead to the failure of the final restoration. The concept of integrated crown-root treatment advocated recently requires clinicians to consider the RCT and final restoration as a whole, rather than simply divided into two parts-endodontic treatment and restorative treatment. As the core content of integrated crown-root treatment, infection control should be taken seriously by clinicians and implemented throughout the whole treatment process, especially in the restorative treatment that is easily overlooked after RCT. Therefore, this article describes the infection control of post-and-core crown restoration, classifies the tooth requiring post-and-core crown restoration, and puts forward the measures of infection control before and during post-and-core crown restoration, in order to provide reference and guidance for clinical practice.
Humans ; Crowns ; Tooth Crown ; Post and Core Technique ; Root Canal Therapy ; Infection Control ; Tooth Fractures

Dental Cementum ; Humans ; Tooth Fractures

OBJECTIVE: To analyze the etiological and clinical characteristics of oral emergency patients under 18 years with dental trauma, and to provide guidance on the prevention and treatment in children and adolescents. METHODS: A retrospective study on the intact data of the dental trauma patients under 18 years from January 2016 to December 2018 in the Department of Oral Emergency in Peking University School of Stomatology was conducted, and the distribution of the patients' gender, age and visiting time, as well as the number and position of traumatic teeth, diagnostic classification, and multiple injury with dental trauma were analyzed. RESULTS: During the period, 54.2% of the first visit dental trauma patients (10 164) were children or adolescents (5 506). The two peak ages were 3-4 and 7-9 years. The incidence of the male was higher than the female in every age group (Wilcoxon test, P < 0.001). From May to June and September to November, there were more cases of dental trauma. The peak time of daily dental trauma cases was from 19:00 to 20:00 (Jonckheere-Terpstra test, P < 0.001). The positions of traumatic teeth in both sides were approximate symmetrical, and maxillary central incisors were the most affected. 52.3% of the patients suffered multiple teeth injuries. Among the permanent teeth trauma, enamel and dentin fracture was the most common (24.7%), followed by concussion (20.5%), sub-luxation (17.9%) and complicated crown fracture (14.4%). And among the primary teeth trauma, subluxation was the most common (31.1%), followed by concussion (14.5%) and lateral luxation (9.5%). 19.7% of the children and adolescent dental trauma patients were also suffered maxillofacial soft or hard tissue injury. CONCLUSION The incidence of dental trauma in children and adolescents is higher than that in adults. There were two age peaks among the children and adolescents patients. Primary teeth and young permanent teeth were usually suffered. Clinical treatment should be considered along with the characteristics of child tooth growth. In order to prevent the occurrence of dental trauma, early orthodontic intervention should be carried out in children with severe overjet. Families, schools and nursery institutions should strengthen the protection against dental trauma.
Adolescent ; Adult ; Child ; Female ; Humans ; Incisor ; Male ; Overbite ; Retrospective Studies ; Tooth Avulsion ; Tooth Fractures/epidemiology* ; Tooth Injuries/epidemiology*

OBJECTIVE: To evaluate the morphology accuracy of direct occlusal veneer using two types of modified stamp-technique, comparing the Results of two types of stamp and different composite resin. METHODS: Model scanner was used to get the original data from the standard resin teeth in plastic model. Two types of stamps were made: solid silicon stamp and transparent silicon stamp. In the study, 54 resin tooth were randomly divided into 9 groups: Groups 1-8 were restored by direct composite resin, using general and bulk-filled composite resin in occlusal veneer (1 mm or 2 mm) with two types of stamp-technique (the solid silicon, and the transparent silicon), and the control group was restored by indirect way using CAD/CAM composite resin restoration by biocopy technique to mimic the original shape of the teeth. After the resin teeth were prepared for occlusal veneer, the direct and indirect composite resins were restored. After the restoration was finished, the data were obtained again by the same model scanner in the plastic model. 3D comparisons were made using the original and restoration data, the average difference and the root mean square of difference (RMS) were recoded from the software. The RMS of all the groups were analyzed using one way ANOVA (α=0.05). RESULTS: The RMS of occlusal surface in solid silicon stamp group was (0.136±0.031) mm, in transparent silicon group was (0.130±0.024) mm, and in control group was (0.130±0.009) mm. There were no significant difference. While the RMS of buccal/lingual surface in solid silicon stamp group was the smallest [(0.135±0.020) mm, P < 0.05], and in transparent silicon group it was (0.147±0.021) mm, and control group (0.153±0.014) mm. The general composite resin using the two types of stamp had the largest occlusal RMS in 2 mm occlusal veneer, which were significantly larger than control group (P < 0.05). CONCLUSION The direct occlusal veneer using two types of modified "stamp-technique" had relatively good morphology accuracy. Direct occlusal veneer using bulk-filled composite resin made with two types of stamp technique had even more accurate morphology than using general composite resin. The solid silicon stamp had a better morphology accuracy in buccal/lingual surface than the transparent silicon stamp.
Composite Resins ; Computer-Aided Design ; Dental Restoration, Permanent ; Humans ; Materials Testing ; Tooth ; Tooth Fractures

Objective To discuss the types, number and diagnostic methods of traumatic tooth fracture in order to provide reference for forensic clinical identification. Methods The 41 cases accepted by Judicial Appraisal Center of Gansu University of Political Science and Law from January 2015 to December 2017, were analyzed by descriptive statistics according to information such as the basic situation, injury manner, type and number of tooth fracture, diagnostic method and expert opinion. Results The 41 cases included 31 males and 10 females. Tooth fracture occurred mainly on the maxillary anterior teeth. The main injury manner of traumatic tooth fracture was collision injury. CT scan improved the accuracy of diagnosis. Conclusion There are gender differences in tooth fracture cases. The part of fracture is related to tooth anatomical characteristics. CT scan can be a priority in tooth fracture diagnosis. Forensic analysis of traumatic tooth fracture should comprehensively consider the types and number of tooth fracture, and define the relationship between tooth fracture and the injury.
Expert Testimony ; Female ; Forensic Medicine ; Humans ; Male ; Sex Factors ; Tomography, X-Ray Computed ; Tooth Fractures

This case presents vertical root fracture with vital pulp in mandibular right first molar. Examinations of the history, clinical tests, laser Doppler flowmetry, and radiographs revealed that the tooth showed positive response to electric pulp testing and was normal compared with the healthy control tooth. This study aimed to use a novel vital preserving surgical technique (microapical surgery and nanometer bioactive materials) to make an effective therapeutic decision for the vital tooth with vertical root fracture.
Dental Pulp ; Humans ; Molar ; Tooth Fractures ; Tooth Root

Biodynamics of mandibular angle fractures has been extensively discussed in the literature in search for the best way to fixate and expedite recovery of trauma patients. Pioneers like Michelet and Champy had the greatest impact on evolving of osteosynthesis in maxillofacial traumatology; they introduced their basic principles frequently used to describe the biomechanics of mandibular fixation. Their concept states when a physiologic load is applied on mandibular teeth a negative tension will be created at superior border and a positive pressure will appear at inferior border. These simple definitions are the basis for the advent of fixation modalities in mandibular angle fracture. This article sought to reassess these principals based on load location via finite elements method.
Biomechanical Phenomena ; Dental Stress Analysis ; Finite Element Analysis ; Fracture Fixation, Internal ; methods ; Humans ; Mandible ; physiopathology ; Mandibular Fractures ; physiopathology ; surgery ; Tooth ; physiology

BACKGROUND: This study was conducted to determine the relationship between third molar (M3) and mandibular fracture.METHODS: Patients with unilateral mandibular angle or condyle fractures between 2008 and 2018 were evaluated retrospectively. Medical records were reviewed regarding the location of fractures, and panoramic radiographs were reviewed to discern the presence and position of ipsilateral mandibular third molars (M3). We measured the bony area of the mandibular angle (area A) and the bony area occupied by the M3 (area B) to calculate the true mandibular angle bony area ratio (area A–B/area A× 100).RESULTS: The study consisted of 129 patients, of which 60 (46.5%) had angle fractures and 69 (53.5%) had condyle fractures. The risk of angle fracture was higher in the presence of M3 (odds ratio [OR], 2.2; p< 0.05) and the risk of condyle fracture was lower in the presence of M3 (OR, 0.45; p< 0.05), than in the absence of M3. The risk of angle fracture was higher in the presence of an impacted M3 (OR, 0.3; p< 0.001) and the risk of condyle fracture was lower in the presence of an impacted M3 (OR, 3.32; p< 0.001), than in the presence of a fully erupted M3. True mandibular angle bony area ratio was significantly lower in the angle fractures than in the condyle fractures (p= 0.003).CONCLUSION: Angle fractures had significantly lower true mandibular angle bony area ratios than condyle fractures. True mandibular angle bony area ratio, a simple and inexpensive method, could be an option to predict the mandibular fracture patterns.
Humans ; Mandible ; Mandibular Fractures ; Medical Records ; Methods ; Molar, Third ; Retrospective Studies ; Tooth, Impacted

Pulp revascularization is an alternative treatment in immature traumatized teeth with necrotic pulp. However, this procedure has not been reported in horizontal root fractures. This is a case report of a 9-year-old patient with multiple horizontal root fractures in 2 upper central incisors that were successfully treated with pulp revascularization. The patient presented for treatment 2 years after the initial trauma, and revascularization was attempted after the initial treatment with calcium hydroxide had failed. Prior to pulp revascularization, cone-beam computed tomography and autoradiograms demonstrated multiple horizontal fractures in the middle and apical thirds of the roots of the 2 affected teeth. Revascularization was performed in both teeth; platelet-rich plasma (PRP) was used in one tooth (#11) and the conventional method (blood clot) was used in the other tooth (#21). Clinical and radiographic follow-up over 4 years demonstrated pulp calcification in the PRP-treated tooth. Neither of the 2 teeth were lost, and the root canal calcification of tooth #11 was greater than that of tooth #21. This case suggests that PRP-based pulp revascularization may be an alternative for horizontal root fractures.
Calcium Hydroxide ; Child ; Cone-Beam Computed Tomography ; Dental Pulp Cavity ; Follow-Up Studies ; Humans ; Incisor ; Methods ; Platelet-Rich Plasma ; Tooth Fractures ; Tooth