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At least 289 records · Page 16Linked to original sources
PubMed1998

Assessment of the apical transportation of root canals using the method of the curvature radius.

The purpose of this investigation was to evaluate the occurrence of apical transportation after root canal instrumentation using only K-Flexofiles or K-Flexofiles intercalated with K-Flexofile Golden Mediums. For this purpose, the degree (Schneider's method) and the radius of the curvature was recorded before and after instrumentation. The results showed that there was no statistically significant difference between the techniques. The correlation between the degree and the radius of curvature of the root canal was not consistent, nor was there a relationship between the original radius of curvature and the apical transportation. However, determination of curvature by use of its radius has proved to be an effective method.

Dental Instruments↗
PubMed1998

Macroscopic and microscopic aspects of incinerated teeth.

Fifty-eight premolars, extracted for orthodontic reasons, were incinerated for one hour in a furnace at temperatures varying from 150 degrees C to 1150 degrees C, increasing at 100 degrees C intervals. Between 150 degrees C and 700 degrees C the teeth changed from light yellow to bluish-white passing through brown. The scanning electron microscope showed that at 150 degrees C cracks appeared in the enamel, increasing in number as the temperature rose. At 450 degrees C the internal surface detached from the dentine and showed the same cracked surface as the exterior. Above 1100 degrees C the enamel fragments had a prismatic structure difficult to identify due to their melted structure. Dentine retained its tubular structure up to 1150 degrees C even when the tubules' diameter decreased at 700 degrees C. The cementum cracked as the temperature increased. Certain cracked areas actually detached at 600 degrees C giving a corroded aspect to the cementum and the residual zones became irregular when the temperature rose and eventually at 1150 degrees C the cementum was no longer identifiable.

Adolescent↗
PubMed1999

Apexification & apexogenesis.

When there is pulpal involvement of permanent teeth with incompletely formed roots, techniques for the induction of apical closure should be completed before endodontic therapy is begun. Apexification is a method of inducing a calcified barrier at the apex of a nonvital tooth with incomplete root formation. Apexogenesis refers to a vital pulp therapy procedure performed to encourage physiological development and formation of the root end.

Adolescent↗
PubMed2006

Labiomandibular paresthesia caused by endodontic treatment: an anatomic and clinical study.

Labiomandibular paresthesia after root canal treatment is an accident that is still too frequent despite the development of new endodontic techniques. The aim of this anatomical and clinical study is to advance the understanding of how accidents occur so as to avoid them. This anatomical study made it possible to determine the variability of proximity of the apex of the tooth root to the mandibular bundle, as well as the relationship between the nerve and its satellite artery, and to understand how endodontic filling material spreads into the cancellous bone. The clinical study, which included examination with conventional radiology as well as with imaging techniques, enabled us to identify the exact location of the filling material in relation to the mandibular bundle and to correlate this to the occurrence of clinical symptoms and their diverse manifestations.

Cranial Nerve Injuries↗
PubMed2003

Clinical evaluation of the measuring accuracy of ROOT ZX in primary teeth.

OBJECTIVE: The aim of this study was to assess the accuracy of an electronic device (Root ZX; Morita, Tokyo, Japan) for measuring the root canal length in primary teeth. STUDY DESIGN: The pulp tissue was removed from 71 nonrestorable teeth scheduled to be extracted under general anesthesia, and the root canals (n = 105) were irrigated (H(2)O(2), 3%; NaOCl, 1%). Subsequently, the length was determined clinically with the electronic device prior to extraction. Treatments were performed by 2 dentists (42 and 63 root canals). After extraction, the real length was recorded and the 2 measurements were compared. RESULTS: Measurements were affected significantly by the dentists (P < .01; chi(2)). However, regression analysis revealed sufficient accuracy of the device, with a tendency to estimate the root canal length just short (x = -0.98 +/- 1.75 mm) of the apex. These results were not influenced by tooth type, root canal type, status of the periapex, or clinical condition (P > .05; chi(2)). CONCLUSION: Root ZX can be strongly recommended for clinical implementation of endodontics in primary teeth, particularly when treating fidgety children.

Analysis of Variance↗
PubMed1998

Tooth devitalization via implant placement: a case report.

This case report documents the devitalization of an adjacent tooth during osteotomy preparation for implant placement. The fixtures were placed without consulting the patient's dentist. Furthermore, radiographs were not taken during stage 1 surgery. The patient started to experience painful symptoms 1 month after fixture placement, and a radiograph was taken at that time. It revealed periapical pathology on the mandibular left canine, through which the base of the implant penetrated. This traumatic injury at the tooth's apex undoubtedly caused its devitalization. Prompt removal of the fixture and endodontic therapy on the canine resulted in repair of the osseous site within 3 months.

Cuspid↗
PubMed1998

Correlation between cortical plate proximity and apical root resorption.

Root resorption is one of the most common iatrogenic sequelae of orthodontic treatment. Recently, root contact with the labial or palatal cortical plate at root apex level during orthodontic tooth movement was reported to be related to root resorption, and dentofacial morphology was suggested to predispose certain persons to root contact with the cortical plate. In this study, we constructed a best-fit straight line for the maxillary palatal cortical plate and set a line for the labial cortical plate from A point to Prosthion point in order to obtain measurements of proximity of root apices with the cortical plates of the maxillary alveolus. We investigated the correlation between apical root resorption and the measured variables. Our findings suggest that root approximation to the palatal cortical plate during orthodontic treatment could explain approximately 12% of the variance observed in the level of root resorption and the maxillary alveolar bone width about 2%. Tooth extrusion and crown lingualization also contributed to root resorption. We concluded that maxillary central incisor apical root resorption is influenced by root approximation to the palatal cortical plate during orthodontic treatment.

Adolescent↗
PubMed2001

Array-projection geometry and depth discrimination with Tuned-Aperture Computed Tomography for assessing the relationship between tooth roots and the inferior alveolar canal.

OBJECTIVES: The purpose of this study is to compare Tuned-Aperture Computed Tomography (TACT) image sets made with linear vertical, linear horizontal, conical, and x-shaped x-ray projection arrays with regard to observer accuracy in (1) measuring the distance from the apex of a tooth root to the middle of the inferior alveolar canal (IAC), (2) measuring the shortest distance from the surface of a tooth root to the surface of the IAC, and (3) determining whether the root is buccal or lingual to the IAC. The same relationships were also examined by means of pairs of images and the buccal object rule. STUDY DESIGN: Two artificial mandible sections with simulated IACs were fabricated. The same human mandibular premolar root was used in both models to prevent development of learning cues to differentiate between models. The models were imaged from both sides, resulting in 4 orientations. An optical bench was designed to precisely orient different beam projection arrays for production of TACT image sets and pairs of images for use with the buccal object rule. Twelve dentists participated as observers to independently assess the relationships between the tooth root and the IAC with regard to the 4 orientations. RESULTS: For measuring the distance from the tooth apex to the middle of the IAC, TACT image sets made from conical and x-shaped arrays proved significantly more accurate than TACT image sets made from linear vertical or linear horizontal projections or pairs of digital images used with the buccal object rule (P <.05). For measuring the shortest distance between the tooth surface and the IAC surface, TACT image sets made from linear vertical, conical, and x-shaped projection arrays were significantly more accurate than measurements made through use of the buccal object rule or TACT image sets made through use of a linear horizontal projection array (P <.05). The following percentages of mistakes were made in determining whether the tooth root was buccal or lingual to the IAC: buccal object rule (58%), linear horizontal array (31%), linear vertical array (2%), conical array (0%), and x-shaped array (0%). CONCLUSIONS: For TACT, images acquired with conical and x-shaped beam projection arrays are preferred to those acquired with linear arrays for assessing the relationship between tooth roots and the IAC. TACT was found to be significantly more accurate than standard application of the buccal object rule for the relationships investigated.

Alveolar Process↗