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At least 1,207 records · Page 67Linked to original sources
PubMed1989

Biomechanical responses of tooth associated with different root lengths and alveolar bone heights: changes of stress distributions in the PDL.

The purpose of the present study was to elucidate the nature of stress distributions in the PDL varied by different root lengths and alveolar bone heights. A three-dimensional model of the upper central incisor was constructed for the finite element method (FEM). The model was modified to produce various root lengths and alveolar bone heights. A lingually directed 100 g horizontal force was applied at a point on the labial crown surface. Stress distributions were determined in the center of the PDL for various apicogingival levels. Stress levels in the PDL gradually decreased with a longer root. Rates of changes in stress levels to those with an original root length were approximately 1.5 at maximum and 0.8 at minimum. Patterns of stress distributions were varied by different alveolar bone heights in both the qualitative and quantitative aspects; i.e., apicogingival level of stress transition shifted more apical, and stress levels also increased following a reduction of the alveolar bone in the apicogingival direction, approaching about eight times with a half alveolar bone height as the original. It is found that the root length and alveolar bone height affect stress distributions in the PDL. Thus, it is shown that an orthodontic force application should be determined on the basis of anatomical variations in root length and alveolar bone height to induce an optimal stress level in the PDL, which is a key to desirable tooth movement.

Alveolar Process↗
PubMed2004

Bone structure effect on root resorption.

OBJECTIVES: To explore if alveolar bone shape and density might promote external apical root resorption. SETTING AND SAMPLE POPULATION: Panoramic radiographs of 700 patients who had orthodontic treatment at Temple University were reviewed and 22 patients with radiographic evidence of root resorption on the lower incisors were selected for the study. Exclusion criteria included a history of systemic diseases, craniofacial abnormalities, tooth injury, endodontically treated teeth, and impacted teeth. METHODS: Pre-treatment (T1) and post-treatment (T2) cephalometric radiographs were converted into digital format and enhanced to reduce contrast variability and improve edge definition. Tooth length, root length, root area, alveolar area around the root including cortical area, area of medullary bone, and area of the symphysis were measured using an interactive software algorithm. A region of interest within the symphysis was also defined and trabecular space area and fractal dimension calculated as an estimate of bone density. RESULTS: Root area and tooth length were correlated negatively with changes in root area, tooth area, and root length. Larger teeth demonstrated a greater amount of root resorption. Dentoalveolar complex dimensions remained relatively unchanged during tooth movement. The amount of alveolar bone around the root, thickness of cortical bone, density of the trabecular network, and fractal dimension showed no significant correlation with the extent of the external apical root resorption. CONCLUSIONS: The results of this study suggest that the density and morphology of the dentoalveolar complex are not significant factors in the etiology of external apical root resorption.

Adolescent↗
PubMed2006

Removal of separated files from root canals with a new file-removal system: Case reports.

There have been many different devices and techniques developed to retrieve instruments fractured during endodontic procedures, but none of them can consistently remove separated instruments from root canals. Iatrogenic accidents such as perforation and canal destruction have been reported during the removal of separated instruments. The file removal process becomes even more difficult when breakage occurs in a curved canal or in the apical third of the canal. Four cases requiring removal of separated files from the apical third of curved canals are presented. All were successfully treated using a newly designed system and technique.

Adolescent↗
PubMed1999

An evaluation of endodontically treated vertically fractured teeth.

For this survey, 92 vertically fractured endodontically treated teeth were evaluated clinically and radiographically before and after extraction. The maxillary second premolars (27.2%) and mesial roots of the mandibular molars (24%) were the most fractured teeth. In 67.4% of the teeth, a solitary buccal pocket was present; in 34.8%, a fistula frequently appeared closer to the gingival margin than to the apical area. A lateral radiolucency or a combination of lateral and periapical radiolucency was found in more than half of the cases. The general practitioners correctly diagnosed vertical root fracture in only one-third of the 92 fractured teeth in this survey.

Adolescent↗
PubMed1998

Peri-radicular inflammation related to dens invaginatus treated without damaging the dental pulp: a case report.

A 12-year-old boy was referred with a discharging sinus tract related to the maxillary left lateral incisor, and with a non-vital maxillary left central incisor. The lateral incisor gave a positive response to sensitivity testing. The lesion did not heal after disinfection of the root canal of the central incisor, but healed subsequently after 'endodontic' treatment of an invagination in the lateral incisor. After 2 years the lateral incisor continued to give a positive response to sensitivity testing.

Child↗
PubMed2000

Management of a horizontal root fracture after previous root canal therapy.

This case report concerns a 9-year-old girl who had a horizontal root fracture of her maxillary left central incisor and had root canal therapy performed by her family dentist immediately after the injury. Because of the incomplete canal obturation, the root canal filling material was removed, and calcium hydroxide therapy was initiated. Healing at the fracture site occurred, with hard tissue forming between the root segments. The coronal segment of the root was then obturated with gutta-percha. The patient later had orthodontic treatment with some movement of the coronal segment. Six-year post-treatment follow-up shows apparent clinical and radiographic success. This case illustrates the potential for repair of a horizontal root fracture after endodontic retreatment of the coronal segment and long-term splinting.

Child↗
PubMed2000

Evaluation of root reinforcement of endodontically treated teeth.

OBJECTIVES: The purpose of this study was to test the root reinforcing capabilities of a glass ionomer sealer and to test whether pretreatment of the instrumented canal to alter or remove the smear layer might enhance the reinforcement. STUDY DESIGN: Ninety single-canaled roots of standardized dimensions were instrumented to International Standards Organization size 45 and were analyzed for resistance to vertical fracture. Six groups were tested (n = 15). RESULTS: No significant difference in fracture resistance was observed between any of the groups. CONCLUSIONS: Under the conditions of this study, reinforcement of endodontically treated mature teeth by placement of adhesive materials in the root was not demonstrated.

Analysis of Variance↗
PubMed2005

An experimental analysis of stresses in simulated flared root canals subjected to various post-core applications.

Cervical root fracture is a major clinical problem in flared root canals treated with different post and core applications. This in vitro study evaluated the stress transfer of different post and core systems to the cervical part of the artificially created flared root canals, by using strain gauges. The post-core systems investigated were: (a) cast post-core system without resin reinforcement, (b) cast post-core system with resin reinforcement, (c) pre-fabricated post and resin core with resin reinforcement. The post-core systems which were cemented on simulated roots were subjected to a load applied at an angle of 45 degrees to the long axis of the simulated roots. The strain gauges which were cemented to the cervical part of simulated roots were connected to the data acquisition module to measure and record the changes in strain data. Specimens restored with resin reinforcement either with cast post-core or pre-fabricated post and resin core transferred the stress to the cervical part of the artificial roots at a rate lower than conventional cast post-core system (P = 0.001; anova and Tukey's post hoc test). It was concluded that the resin reinforcement of root canals before post-core applications reduces the stresses at the cervical part of the root surfaces.

Dental Restoration Failure↗
PubMed1989

Comparison of oral radiographic findings among 35-year-old Oslo citizens in 1973 and 1984.

The purpose of the present study was to evaluate a variety of radiographically detectable conditions found on orthopantomograms of 141 individuals as a part of an oral health survey of 35-year-old Oslo citizens, born 1949. Radiographic findings were recorded and compared with those of a similar study made in 1973. The findings revealed a statistically significant reduction in the prevalence of marginal bone loss. The frequencies of endodontically treated teeth and teeth with apical radiolucencies were unchanged.

Adult↗
PubMed1992

Effect of root canal infection and treatment of traumatized primary incisors on their permanent successors.

The purpose of the present retrospective study was to evaluate the effect of trauma, root canal infection and treatment of non-vital primary incisors on their permanent successors. A total of 117 permanent central incisors were examined clinically and radiographically for the presence of discolorations, hypoplasia, or disturbances in root development. Of these, 29 were succedaneous to traumatized, endodontically involved and treated primary incisors (Group A). Another 29 had their traumatized, endodontically involved, primary predecessors extracted or left untreated (Group B). The remaining 59 incisors were intact and had no history of trauma (Group C). Severe hypoplasia could not be observed in any of the teeth, and no disturbances in root development could be disclosed radiographically. The incidence of defects in Groups B and C was similar, whereas in Group A it was 2 or 3 times higher than in each of the other two groups. Despite this fact, root canal treatment of traumatized non-vital primary incisors should be considered a treatment option, as premature extraction of a primary incisor may lead to speech problems, premature eruption and/or malalignment of the permanent successor, or affect the child's self image.

Chi-Square Distribution↗
PubMed2004

Conservative endodontic treatment of teeth fractured in the middle or apical part of the root.

According to treatment type, root-fractured teeth with pulp necrosis or exposed pulps were divided into five groups, group 1: 17 teeth in which the root canal of the coronal fragment only was filled with gutta-percha (GP); group 2: seven teeth in which the root canals of the coronal and apical fragments were both filled with GP; group 3: 19 teeth in which the coronal fragment was filled with GP and the apical fragment was surgically removed; group 4: 68 teeth where the root canal of the coronal fragment was treated with calcium hydroxide and subsequently filled with GP; and group 5: five vital teeth with root and concomitant crown fractures in which the exposed pulps were treated by partial pulpotomy. The frequency of periodontal healing was 76% in group 1, zero in group 2, 68% in group 3 and 86% in group 4. Compared with groups 1 and 2 combined, healing in group 4 was significantly more frequent. In groups 1, 2 and 4, failures occurred significantly more often in teeth showing overfilling, i.e. protrusion of GP into the space between the fragments, compared with teeth without overfilling. All five teeth in group 5 showed healing. It was concluded that root canal filling with GP of the coronal fragment only, with or without surgical removal of the apical fragment, can be successful in selected cases. Treatment of the root canal with calcium hydroxide followed by GP filling appears to be the treatment of choice in root-fractured non-vital teeth. Partial pulpotomy of exposed pulps in five teeth showed results similar to root-unfractured teeth with pulp exposure treated with this technique.

Adolescent↗
PubMed2006

Traumatic intrusion of permanent teeth. Part 1. An epidemiological study of 216 intruded permanent teeth.

An epidemiological study of traumatic intrusion of permanent teeth was performed on 216 teeth in 151 patients treated over a 50-year period at a major trauma center in Denmark (Copenhagen). This analysis showed that intrusion of permanent teeth was of rare injury only affecting 1.9% of traumatic injuries involving permanent teeth. The main etiologic factor appeared to be falling which resulted in axial impacts on maxillary or mandibular teeth. The most common injury patterns were intrusion without additional injuries (33.5%) and intrusion with crown fractures (60.5%). A few cases were combinations of intrusion and either crown/root-fractures or root fractures (6%). Most often one tooth was intruded (46.3%), followed by two teeth (32.4% ) and three or more teeth (21.3%). The majority of intruded teeth were displaced 2-8 mm. The age group of 6-12 years of age was most frequently involved and boys appeared to experience intrusion injuries more frequently than girls, and at an earlier age. Maxillary central and lateral incisors are the primary victims of intrusions and this seems to be identical to other trauma types and is possibly related to the known exposure to impacts of maxillary incisors. The reliability of clinical findings, such as lack of mobility (81.8%), metallic percussion tone (72.5%), and no pain to percussion (66%) was reasonably high, whereas a radiographic feature such as the obliteration of the periodontal ligament space appeared to be only a partly reliable diagnostic tool (52%).

Accidental Falls↗