Tooth resorption is an idiopathic destructive disease of dental hard tissues. The etiology and pathogenesis remain obscure. It has various manifestations and can be commonly classified as internal tooth resorption and external root resorption on the basis of the resorptive lesion sites. There have been many attempts to make further classification based upon the pathological manifestations in recent years. Radiographic examination is an effective tool to assist in the diagnosis. There are few systematic researches on tooth resorption worldwide, most of which are case reports. This review elaborates on the research progress of tooth resorption from aspects of pathogenesis and classification.
Humans ; Root Resorption/diagnostic imaging* ; Tooth Resorption/diagnostic imaging*

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

OBJECTIVETo observe the microstructure changes of rat alveolar bone around tooth root under orthodontic force loading.

METHODSTen 10-week-old rats were included in the study. Upper first molars were moved mesially with 0.196 N of force. The alveolar bone around the root of upper first molar was scanned by a micro-computed tomography scan system (SkyScan-1076) in different period after the initiation of orthodontic force loading (on the 3rd, 7th, 14th day after force loading) and analyzed by a specially-designed software to measure the microstructure parameters of alveolar bone (bone volume fraction, bone surface to volume ratio, structure model index, trabecular thickness, trabecular separation, trabecular number).

RESULTSFrom the 7th day, bone volume fraction [(41 ± 14)%], structure model index (1.51 ± 0.52) and trabecular separation [(90 ± 30) µm] changed significantly in the compressive area compared with those [(64 ± 15)%, (0.51 ± 0.85), (56 ± 10) µm] on the 3rd day. From the 14th day, bone volume fraction [(78 ± 14)%], structure model index (0.28 ± 0.20) and trabecular separation [(29 ± 13) µm] changed significantly in the tension area compared with those [(67 ± 14)%, (0.40 ± 0.41), (48 ± 15) µm] on the 7th day. No difference on trabecular number was found between the compressive area and tension area (P > 0.05).

CONCLUSIONSThe significant resorption of the alveolar bone was observed on the 7th days in the compressive area and the deposition of the alveolar bone was observed on the 14th day in the compressive area after orthodontic force loading.

Alveolar Process ; diagnostic imaging ; ultrastructure ; Animals ; Dental Cementum ; diagnostic imaging ; Male ; Molar ; diagnostic imaging ; Rats ; Rats, Sprague-Dawley ; Root Resorption ; diagnostic imaging ; Tooth Movement Techniques ; Tooth Root ; diagnostic imaging ; ultrastructure ; X-Ray Microtomography

The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography (CBCT). Forty-six patients undergoing orthodontic treatments and having impacted canines in Tongji Hospital were examined. The images of CBCT scans were obtained from KaVo 3D exam vision. Angular and linear measurements of the cusp tip and root apex according to the three planes (mid-sagittal, occlusal and frontal) have been taken using the cephalometric tool of the InVivo Dental Anatomage Version 5.1.10. The measurements of the angular and linear coordinates of the maxillary and mandibular canines were obtained. Using this technique the operators could envision the location of the impacted canine according to the three clinical planes. Adjacent teeth root resorption of 28.26 % was in the upper lateral incisors while 17.39% in upper central incisors, but no lower root resorption was found in our samples. Accurate and reliable localization of the impacted canines could be obtained from the novel analysis system, which offers a better surgical and orthodontic treatment for the patients with impacted canines.
Adolescent ; Adult ; Cephalometry ; methods ; Child ; Cone-Beam Computed Tomography ; methods ; Cuspid ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; methods ; Incisor ; diagnostic imaging ; Male ; Maxilla ; diagnostic imaging ; Reproducibility of Results ; Root Resorption ; diagnostic imaging ; Tooth, Impacted ; diagnostic imaging ; Young Adult

OBJECTIVETo evaluate the alveolar bone thickness and root length changes of anterior teeth with cone-beam computed tomography (CBCT).

METHODSCBCT scans were taken for 12 skeletal Class III patients who accepted the improved corticotomy (IC) procedures during pre-surgical orthodontics. The CBCT data in T1 (the maxillary dental arch was aligned and leveled) and T2 (extraction space closure) were superimposed and the alveolar bone thickness at root apex level and root length measurements were done.

RESULTSFrom T1 to T2, the buccal alveolar bone thickness for the upper lateral incisors increased from (1.89±0.83) to (2.47±1.02) mm (P<0.05), and for central incisors and for canines from (2.32±0.71) to (2.68±1.48) mm and from (2.28±1.08) to (2.41±1.40) mm, respectively. According to Sharpe Grading System, the root resorption grade for 69 teeth of 72 was located in Grade 1, two teeth in Grade 2, one tooth in Grade 3.

CONCLUSIONSThe improved corticotomy had the potential to increase the buccal alveolar bone thickness and the root resorption in most teeth was in Grade 1 according to Sharpe grading system.

Alveolar Process ; anatomy & histology ; diagnostic imaging ; surgery ; Cone-Beam Computed Tomography ; Cuspid ; Humans ; Incisor ; Malocclusion, Angle Class III ; diagnostic imaging ; surgery ; Root Resorption ; pathology ; Tooth Root ; Zygoma

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

The aim of this retrospective study was to quantitatively evaluate the treatment effects of intrusion of overerupted maxillary molars using miniscrew implant anchorage and to investigate the apical root resorption after molar intrusion. The subjects included 30 patients whose average ages were 35.5±9.0 years. All patients had received intrusion treatments for overerupted maxillary molars with miniscrew anchorage. There were 38 maxillary first molars and 26 maxillary second molars to be intruded. Two miniscrews were inserted in the buccal and palatal alveolar bone mesial to the overerupted molar. Force of 100-150 g was applied by the elastic chains between screw head and attachment on each side. Lateral cephalograms and panoramic radiographs taken before and after intrusion were used to evaluate dental changes and root resorption of molars. Only 6 of the 128 miniscrews failed. The first and second molars were significantly intruded by averages of 3.4 mm and 3.1 mm respectively (P<0.001). The average intrusion time was more than 6 months. The crown of the molars mesially tilted by averages of 3.1 degrees and 3.3 degrees (P<0.001) for first and second molars. The amounts of root resorption were 0.2-0.4 mm on average. The intrusion treatment of overerupted molars with miniscrew anchorages could be used as an efficient and reliable method to recover lost restoration space for prosthesis. Radiographically speaking, root resorption of molars was not clinically significant after application of intrusive forces of 200 to 300 g.
Adult ; Bone Screws ; Cephalometry ; Dental Implantation ; Female ; Humans ; Male ; Maxilla ; Middle Aged ; Molar ; diagnostic imaging ; surgery ; Orthodontic Anchorage Procedures ; instrumentation ; methods ; Radiography, Dental ; methods ; Retrospective Studies ; Root Resorption ; diagnostic imaging ; surgery ; Tooth Movement Techniques ; instrumentation ; methods ; Young Adult

OBJECTIVETo investigate the effect of ridge preservation with Bio-Oss Collagen and Bio-Gide in posterior sites.

METHODSFrom May 2010 to July 2013, 16 patients with bilateral posterior teeth planned to be extracted and replaced by implants were enrolled. One of the sockets was randomly selected and presserved with Bio-Oss Collagen and Bio-Gide (intervention group). The contralateral socket was left to heal spontaneously (control group). Cone-beam (CBCT) scans were performed immediately after the extraction and 6 month later. The bone cores were collected during the implant placement surgery and analyzed by micro-computed tomography.

RESULTSAfter 6 month healing, the vertical and horizontal dimensional alteration of the treatment group were (0.55 ± 1.05) mm and (-0.99 ± 0.94) mm respectively, while the vertical and horizontal change of control group were (-0.71 ± 1.41) mm and (-2.26 ± 1.29) mm respectively. The micro-computed tomography results showed that there was no significant difference in new bone volume between control and intervention groups.

CONCLUSIONSApplying Bio-Oss Collagen and Bio-Gide for ridge preservation in posterior sites resulted in less vertical and horizontal bone resorption of sockets following extraction.

Alveolar Process ; diagnostic imaging ; Biocompatible Materials ; therapeutic use ; Bone Resorption ; prevention & control ; Collagen ; therapeutic use ; Heterografts ; Humans ; Minerals ; therapeutic use ; Organ Sparing Treatments ; methods ; Tooth Extraction ; Wound Healing ; X-Ray Microtomography