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At least 595 records · Page 33Linked to original sources
PubMed1995

An in vivo evaluation of the ENDEX and RCM Mark II electronic apex locators in root canals with different contents.

The accuracy of many apex locators is affected by electrolytes including sodium hypochlorite. According to the manufacturer a new device, the ENDEX, overcomes this problem. The purpose of this study was to assess the accuracy of the ENDEX in comparison with a traditional device, the RCM Mark II. The lengths of 61 canals with various contents (vital pulp, necrotic pulp, pus/exudate, sodium hypochlorite, and water) were determined in vivo. Files were cemented within the canals at lengths determined by the ENDEX. The teeth were then radiographed and extracted, and the distance between the file tip and apical foramen was recorded. Derived readings for the RCM Mark II were compared with the actual ENDEX reading and corresponding radiograph. The results indicated that most of the file tips that were at the radiographic apex actually extended through the apical foramen, and canal content had a varying effect on each device. The overall accuracy of the ENDEX (71.7%) was higher than that of the RCM Mark II (43.5%) within 0.5 mm of the apical foramen. The ENDEX, unlike the RCM Mark II, proved accurate in the presence of sodium hypochlorite.

Chi-Square Distribution↗
PubMed1995

Electronic canal length measurement.

The most important advantage of the electronic method is that it can measure the length of the root canal to the end of the apical foramen, not to the radiographic apex. The most striking disadvantage of the electronic method is that if strong electrolytes are in the root canal, the meter shows a reading that is too high (obtaining a short working length), or sometimes the measurement itself becomes impossible. Recently new electronic devices have been developed. These devices can make an accurate measurement of the root canal length, even if a strong electrolyte is present in the root canal. These new devices allow the dentist to enlarge the apical portion of the canal more precisely than when the radiographic method is used.

Dental Pulp Cavity↗
PubMed1996

Dose reduction of two digital sensor systems measuring file lengths.

OBJECTIVE: The aim of this study was to determine the effect of dose reduction on the image quality of two sensor systems with automatic greyscale adjustment. STUDY DESIGN: Two digital sensor systems, Sidexis (Siemens, Bensheim, Germany) and Digora (Soredex, Helsinki, Finland), were tested. The image quality of the systems was determined by comparing lengths of endodontic files (025, 020, 015, and 010 files) and a premolar root in the digital images with lengths on conventional radiographic films. For the experiments the exposure was changed to 100%, 50%, 25%, 12.5%, 6.25%, and 3.125% of that for Ektaspeed films. RESULTS: The lengths of 025 and 020 files and the premolar root in the digital images were comparable with the lengths on films even if the exposure was reduced to 6% of that used for Ektaspeed films. The lengths of 015 files reduced as the exposure was reduced. The lengths of 010 files were significantly shorter than the lengths on films. CONCLUSIONS: With the systems tested, a dose reduction of approximately 95% compared with Ektaspeed films is possible to determine the lengths of a premolar root and 025 and 020 files. For thinner objects a dose reduction is questionable.

Analysis of Variance↗
PubMed1996

Osteopathia striata, short stature, cataracts, and microdontia: a new syndrome? A case report.

A case of osteopathia striata, childhood cataracts, short stature, elbow deformity, and microdontia with rhizomicry in a white male is reported. The report includes a detailed analysis of dental changes. The relationship of this syndrome to other similar conditions including osteopathia striata with cranial base sclerosis and Rothmund-Thomson syndrome are discussed.

Bone Diseases, Developmental↗
PubMed1996

Determination of location of root perforations by electronic apex locators.

OBJECTIVES: This study was conducted to evaluate the accuracy of two electronic apex locators, the Sono Explorer Mark 2 Junior (Hakusui, Osaka, Japan) and Apit 2 (Osada, Tokyo, Japan) in detecting root perforations. The adequacy of radiographs for identifying root perforations was also assessed. STUDY DESIGN: Thirty-two extracted human teeth were perforated in the middle third of the root and embedded in alginate. Determination of all perforations were carried out with K-files no. 25 attached to the apex locators tested. Two radiographs were taken at two angulations after each electronic measurement. The actual location of the file tip in relation to the perforation was determined with a stereomicroscope. A total of 512 radiographs were evaluated to attempt to identify root perforations. RESULTS: The mean distance of the file tip from the external outline of the root surface was short for both instruments. A statistical difference (p < 0.05) was found between the two apex locators in dry canals or if saline solution was present. There was no significant difference between the two instruments in the presence of sodium hypochlorite. Evaluators radiographically identified 45% of the root perforations when located in buccal-lingual directions. CONCLUSION: Under the in vitro conditions of this study, both devices determined the location of the perforations in an acceptable clinical range short of the root surface. Radiographs were found to be less reliable in identification of perforation locations.

Chi-Square Distribution↗
PubMed1996

Examination of external apical root resorption with scanning electron microscopy.

UNLABELLED: External apical root resorption may be evident histologically but not visible radiographically until it is advanced. If working length is determined without considering this resorption, overinstrumentation or overfilling may occur. OBJECTIVE: This study used scanning electron microscopy to examine the appearance and to compare the incidence of external apical root resorption in 40 teeth with differing pulpal and periapical diagnoses. STUDY DESIGN: After extraction, 46 roots were sectioned horizontally 6 mm from the anatomic apex and prepared for scanning electron microscopy examination. Photomicrographs were scored by two blinded independent examiners. Apical resorption was categorized as: none, partial, or complete. Presence or absence of a funneling appearance of the resorption was also recorded. RESULTS: Kruskal Wallis showed a significant difference in resorption between groups; teeth with irreversible pulpitis/normal periapex had the least resorption. Duncan's multiple range test found radiographic apical lesions to have more resorption than those without lesions; teeth with necrotic pulps had more resorption than those with vital pulps. CONCLUSION: Pulp necrosis with radiolucent apical pathosis is more likely to demonstrate resorption.

Chi-Square Distribution↗
PubMed1998

Endodontic working length assessment. Comparison of storage phosphor digital imaging and radiographic film.

OBJECTIVE: This study compared the difference in interpretation of the position of endodontic file tips between two imaging systems: photostimulable storage phosphor luminescence imaging versus radiographic film. STUDY DESIGN: Thirteen patients were selected at random. Preoperative and trial file length radiographs were made with a dual image receptor composed of a Digora Digital Imaging Plate and a piece of Ektaspeed Plus film. Exposure techniques for E-speed film were used. Root length and file length measurements were made from digital images with the Digora system's measuring tools. Measurements were also made on radiographic film with a 7 x measuring magnifier. Root length, file length, and their difference were compared for both film and digital images. RESULTS: Differences were found to be less in digital than in film images. Photostimulable storage phosphor luminescence imaging performed similarly to Ektaspeed Plus film for measuring root lengths, but file tip positions (especially of small file sizes) were difficult to visualize with E-speed film. CONCLUSIONS: The smaller difference between file tip and root apex found with digital imaging suggests that this technique is more accurate to assess trial file length. This imaging modality for assessing file positions during root canal treatment may be beneficial to the practitioner.

Bicuspid↗
PubMed1998

Validity of radiographic measurement of interproximal bone loss.

The aim of the present study was to compare radiographic assessment of interproximal bone loss using a loupe with a 0.1 mm calibrated grid and a computer-assisted analysis system (LMSRT). In 35 patients suffering from untreated advanced periodontal disease, 62 standardized radiographs were taken presurgically. The horizontal and vertical angulation difference of the central beam from the orthoradial projection was calculated for each radiograph. At the time of surgery, for 115 interproximal defects, the distances from the cementoenamel junction (CEJ) to alveolar crest (AC), and CEJ to bottom of the bony defect (BD) were measured. In all radiographs, the linear distances CEJ to AC, and CEJ to BD were assessed using a loupe and LMSRT. Comparison between radiographic and intrasurgical assessments was performed using paired t-tests. A stepwise multiple linear regression analysis was used to evaluate factors that influence the discrepancy between radiographic and intrasurgical measurements. Both analyzing techniques underestimated interproximal bone loss as compared with intrasurgical measurements (CEJ-AC: loupe: 0.86 +/- 1.84 mm [p < 0.001]; LMSRT: 0.58 +/- 1.86 mm [p < 0.005]; CEJ-BD: loupe: 1.22 +/- 2.33 mm [p < 0.001]; LMSRT: 0.80 +/- 2.09 mm [p < 0.001]). LMSRT underestimated interproximal bone loss significantly less than the loupe (p < 0.001). The difference between LMSRT and intrasurgical assessments was modulated by the factors of vertical and horizontal angulation difference and defect depth (p < 0.1). Orthoradial projection reduced underestimation of radiographic assessment of bone loss. LMSRT underestimated interproximal bone loss to a lesser extent than conventional evaluation by loupe.

Alveolar Bone Loss↗
PubMed1999

Radiographic evaluation of mandibular third molar eruption space.

OBJECTIVE: The purpose of this study was to investigate variables in third molar and arch dimensions among subjects with impacted and erupted mandibular third molars. STUDY DESIGN: Standardized panoramic radiographs were taken for 134 subjects (60 males and 74 females with 213 third molars) with an average age of 19.8 years. For the impacted group, only those who had mesioangular inclination of the third molars were recorded. The radiographic features studied were angulation of tooth, level of eruption, development of root, mesiodistal crown width, retromolar space, and gonial angle. RESULTS: Third molar angulation in the impacted group (69 subjects with 101 third molars) averaged 16.28 degrees (SD +/- 11.88 degrees), with no significant gender differences. The retromolar space was significantly smaller in the impacted group than in the erupted group (P < .001). This space was also the only significant variable (P < .05) associated with lateral asymmetry in the eruption/impaction status of third molars. In the impacted group, 83% of subjects had third molar space/crown width ratios less than 1, whereas in the erupted group 69% had ratios of at least 1. The average space/crown width ratios in the impacted and erupted groups were 0.78 and 1.06, respectively (P < .001). The impacted and erupted groups did not differ significantly with respect to mesiodistal crown width and gonial angle. Approximately 76% of impacted third molars had complete root formation, 20% had two thirds root formation, and only 4% displayed one third root formation. Of the impacted third molars, 66% were partially erupted and the rest were unerupted. There was a strong positive relationship between frequency of third molar impaction and degree of angulation (P < .001), but the former was inversely associated with retromolar space (P < .001). CONCLUSIONS: The most significant variable associated with third molar impaction is inadequate space. The vast majority of impacted third molars had space/crown width ratios of less than 1.

Adolescent↗
PubMed2003

Root surface areas in long-term survivors of childhood cancer.

Treatment regimes for childhood cancer are known to affect the root development in the long-term survivors (LTS) but the available the data is subjective in nature with very few quantitative data in the literature. This study aimed to quantify the root surface area (RSA) of mandibular teeth in LTS compared with controls and relate this to the treatment regime and also to the age at which the cancer was diagnosed. Panoramic radiographs were obtained from 69 LTS and an equal number of appropriately matched healthy controls. RSA were calculated using Computer Linked Image Analysis. RSA in the LTS were found to be significantly smaller as compared with controls. Also, RSA were the least in those LTS who had Total Body Irradiation followed by Bone Marrow Transplantation (TBI/BMT) compared with other treatment regimes, the difference being statistically significant for all teeth studied. There was no relationship between the RSA and the age at which the cancer was diagnosed. Smaller root areas have implications for the oral health of LTS, as bone loss around such teeth will compromise further their periodontal support thus jeopardising the long-term survival of the tooth.

Adolescent↗
PubMed2004

Tooth morphometry in lingual orthodontics.

Lingual orthodontics is used clinically. This study investigated the lingual crown angulation and inclination of optimal occlusion in Taiwanese people. The sample included 45 sets of dental study casts from 28 males and 17 females with optimal occlusion selected from approximately 5,000 young adults. Mesial tipping occurred in all teeth except the upper second molars, the lower central incisors, and the lower lateral incisors. The greatest mesial tipping was observed in the lower second molars. The greatest distal tipping was observed in the lower lateral incisors. Labial (buccal) inclination was observed in all teeth except the lower first molars and the lower second molars. Maximum labial inclination occurred in the upper central incisors. Maximum lingual inclination was observed in the lower first molars.

Adolescent↗
PubMed1986

Metric analyses of the teeth and faces of South Australian twins.

Procedures are described for the acquisition and analysis of data in a study of the dental and facial characteristics of South Australian twins. Comparisons of the mesiodistal diameters of maxillary incisors in MZ and DZ twins revealed heterogeneity of total variances and evidence of inequality of mean values for some dimensions between MZ and DZ twins. Previous estimates of heritabilities for tooth size, relying on classical assumptions in twin research, may be exaggerated. A preliminary analysis of facial shape was undertaken using a procedure for shape matching based on a least squares fit of homologous coordinates. There was evidence of mirror-imaging in some MZ twin pairs and differences in facial asymmetry between male and female DZ twins. Future extensions of the study using methods for three-dimensional shape analysis are described.

Adolescent↗
PubMed1979

Association of twin zygosity with the mean and variance of tooth size.

To search for an association of twin zygosity with tooth size, 56 dental variables measured from 65 pairs of twins (43 MZ, 22 DZ) were studied. Results of the t' test for equality of the means showed no association of zygosity with any of the variables in males or in females. Results of the F' test for homogeneity of total variances between zygosities showed evidence for unequal total variances in 15 variables in males and 13 in females. Sex influence was further noted on the association of zygosity with the variance of tooth size. Where total variances were unequal, genetic variance estimates differed when only the within-pair mean squares were used and when combined estimates designed to be unbiased by differences in environmental variances were used.

Female↗
PubMed1999

Implant supported single-tooth replacements compared to contralateral natural teeth. Crown and soft tissue dimensions.

The aim of this study was to make a comparative evaluation of crown and soft tissue dimensions between implant-supported single-tooth replacements and the contralateral natural tooth. Twenty patients, who had been treated with an implant-supported single-tooth replacement in the esthetic zone of the maxillary jaw and had i) a non-restored contralateral natural tooth and ii) completed the implant-supported crown restoration at least 6 months prior to the scheduled follow-up examination, were included in the study. At the re-examination various variables describing crown form, soft tissue dimensions and soft tissue conditions were assessed. In addition, the patient's overall satisfaction with the esthetic outcome of the implant-supported single crown was scored using a Visual Analogue Scale (VAS). In 12 of the subjects clinical photographs were available from the time of crown insertion for evaluation of longitudinal alterations of the papilla height. The results revealed that, in comparison to the contralateral natural crown, the implant supported crown i) was longer, ii) had a smaller facio-lingual width, iii) was bordered by a thicker facial mucosa, iv) had a lower height of the distal papilla, v) showed a higher frequency of mucositis and bleeding on probing and vi) showed greater probing depths. The longitudinal evaluation of the papillae adjacent to the implant crown showed an improved proximal soft tissue fill at the follow-up examination. The VAS scoring of the patients' satisfaction with the appearance of their single implant-supported restorations revealed a median value of 96% with a range from 70 to 100%. Hence, observed differences in clinical crown height and soft tissue topography between implant-supported single-tooth replacements and the contralateral natural tooth may in most patients be of minor importance for the appreciation of the esthetic outcome of implant therapy.

Adolescent↗
PubMed1999

Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man.

The purpose of this investigation was to analyze the clinical crown of the 3 tooth groups of the maxillary anterior sextant of the permanent dentition of normal subjects with respect to (i) width, length and the width/length ratios and (ii) determine if there is a correlation between tooth dimensions or tooth group ratios and subject height. Subjects (> or = 20 y.o.) were recruited for this study if (i) the free gingival margin on the facial surface of teeth in the maxillary sextant was positioned apical to the cervical bulge, (ii) there was no evidence of attachment loss; as determined by lack of a detectable CEJ and (iii) the marginal tissue was knife edged in form, firm in consistency and coral pink in color. Teeth were excluded if (i) there was evidence of gingival alteration, i.e., gingival overgrowth/hyperplasia, inflammation, altered passive eruption, attachment loss, gingival recession or history of periodontal surgery, or (ii) there was evidence or history of incisal edge/proximal tooth alteration as in, i.e., restorative intervention, traumatic injury or occlusal wear into dentin. At least 1 suitable tooth from each tooth group of the maxillary anterior dentition had to be present. A maxillary impression was taken and poured in yellow die stone. The widest mesial-distal portion and the longest apical-coronal portion of the test teeth were measured. Gender, ethnicity and subject height (SH) were recorded for each participant. Due to a limited ethnic diversity only data from the Caucasian group were analyzed. The mean coronal tooth width (mm) of males versus females was CI: 8.59 versus 8.06, LI: 6.59 versus 6.13 and CA: 7.64 versus 07.15. The mean coronal tooth length (mm) of males versus females was CI: 10.19 versus 9.39, LI: 8.70 versus 7.79 and CA: 10.06 versus 8.89. All width and length measures were significantly greater for males than for females. The mean coronal tooth width/length ratios for males versus females was CI: 0.85 versus 0.86, LI: 0.76 versus 0.79 and CA: 0.77 versus 0.81. A comparison between genders of the width/length ratios of the CI and LI were found not to differ, however the CA ratio for females was significantly greater than for males. A statistically significant difference was found to exist between the mean (cm) SH for males versus females: 181.2 versus 164.0. A positive correlation (p < or = 0.0001 to 0.0691) was found to exist between tooth group width/height ratios within genders. No significant correlation was found between any of the tooth dimensions or tooth group ratios and SH. The results of this study indicate that within male and female Caucasians, the mean width/length ratio of the maxillary 3 anterior tooth groups is 0.81. As well, within both genders there is a positive correlation between tooth group width/length ratios. The significance of these findings with respect to periodontal mucogingival plastic surgical procedures is discussed.

Adult↗