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PubMed2002

A comparison of D-, E-, and F-speed conventional intraoral radiographic films in endodontic measurement.

OBJECTIVES: We sought to compare observer measurement error and subjective ratings for International Standards Organization D-, E-, and F-speed direct exposure dental x-ray films used to determine endodontic working lengths. METHODS: Radiographs were exposed to achieve a standard background density of approximately 2.0. Three human maxillary posterior teeth for which No. 10 K-files had been placed at various lengths within 4 canals were studied in a cadaver section. A total of 30 radiographs were used (10 from each film type). Five licensed dentists excluding all authors viewed the radiographs independently and in random sequence. Distances from the file tips to the radiographic apices were measured and were compared with known lengths for error determination. The observing dentists also subjectively rated the images as desirable or undesirable. Statistical methods included a 3-factor ANOVA with Tukey honestly significant difference post hoc analysis to compare objective measurements and chi-square with respect to subjective ratings. RESULTS: No significant differences were attributable to film speed grouping or observers (P > .05); however, there was a specimen effect in that a significant difference was found in measurement accuracy among the 4 canals (P < .05). Differences in subjective ratings for the 3 film types were not statistically significant (P > .05). CONCLUSION: All 3 film types were similar in objective and subjective ratings. This being the case, the faster film is preferred to minimize the radiation dose to the patient.

Adult↗
PubMed2003

A comparison of the shaping abilities of 4 nickel-titanium rotary instruments in simulated root canals.

OBJECTIVE: The purpose of this study was to compare the root canal shaping abilities of 4 nickel-titanium rotary instruments. STUDY DESIGN: ProFile, GT Rotary, Quantec, and ProTaper files were used to instrument 48 simulated curved root canals in plastic blocks with the crown-down technique. One operator prepared all the canals until reaching an apical canal size of #30. The instrumentation time, changes of canal dimension and curvature, canal aberration, and instrument deformation were evaluated. Data were analyzed by using one-way analysis of variance followed by the Duncan multiple range test. RESULTS: The ProTaper took significantly less instrumentation time, removed more canal wall (especially at the inner side of the canal curve), lessened the canal curvature, and induced more instrument deformation than did the other instruments. CONCLUSION: Although ProTaper files cut more canal wall more quickly than the other instruments in the curved canal, they were also the instruments that most frequently became deformed.

Analysis of Variance↗
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↗
PubMed2001

A reliability study of clinical tooth wear measurements.

STATEMENT OF PROBLEM: Most studies examining tooth wear severity have been performed on dental casts. This indirect approach has limited applicability to dental practice because during the assessment of the casts, the identification of dentin exposure is difficult or even impossible. PURPOSE OF STUDY: The purpose of this study was to assess occlusal and incisal tooth wear clinically to determine the reliability of the assessment procedure and to establish the influence of selected relevant clinical variables (dental quadrant, tooth type, and severity of wear) on the reliability. MATERIAL AND METHODS: Forty-five volunteers (17 men, 28 women; mean age 33.7 +/- 10.7 years), 32 with temporomandibular disorders and 13 free from signs and symptoms of such disorders, were evaluated on 4 occasions. Two trained observers graded tooth wear at 2 different points in time with a 5-point ordinal scale developed for use in this study. The inter-rater and intra-rater reliability of the scale was expressed as Cohen's kappa. The influence of 2 clinical variables, dental quadrant and tooth type, on the values of kappa was tested with 1-way analysis of variance and post hoc Bonferroni tests. Probability levels of P< .05 were considered statistically significant. The influence of the final clinical variable, severity of wear, was assessed qualitatively. RESULTS: The overall values of the inter-rater and intra-rater reliability were substantial (kappa = 0.632 to 0.678). The clinical variable dental quadrant did not influence the kappa values, whereas the inter-rater reliability during the first session was better for incisors and canines than for premolars (1-way analysis of variance: F(3,23)=4.577, P=.012; post hoc Bonferroni tests: P=.030 and.036). Qualitative assessment of severity of wear indicated that the more advanced the tooth wear, the more reliably it could be graded. CONCLUSION: By means of the developed 5-point ordinal scale and within the limitations of this study, it was concluded that tooth wear can be assessed reliably in the clinical dental setting.

Adult↗
PubMed2001

The relationship between intercanthal dimension and the widths of maxillary anterior teeth.

STATEMENT OF PROBLEM: One of the difficult aspects of complete denture prosthodontics is the selection of appropriately sized maxillary anterior teeth. Many attempts have been made to establish methods of estimating the combined width of maxillary anterior teeth and/or central incisors. PURPOSE: The aim of this investigation was to determine whether a relationship exists between the intercanthal dimension and 4 mesiodistal width combinations of the maxillary anterior teeth. MATERIAL AND METHODS: The maxillary anterior teeth of 443 adult subjects were examined. Intercanthal distance was measured between the median angles of the palpebral fissure. The mean widths of the 2 central incisors, the combined widths of the central incisors, the combined width of the 4 incisors, and the combined width of the 6 anterior teeth were determined intraorally at their widest dimension. Pearson correlation coefficients were calculated to determine the relationship between intercanthal distance and the 4 measurements of maxillary anterior teeth (alpha=.05). RESULTS: Although the Pearson correlation coefficients were relatively small, a significant relationship existed between intercanthal dimension and the 4 maxillary teeth dimensions (P<.0001). It was found that biometric ratios of 1:0.267 and 1:1.426 could be used to estimate the central incisor width and the combined widths of the 6 anterior teeth, respectively. CONCLUSION: Within the limitations of this study, the results suggest that intercanthal distance can be used as a preliminary method for determining the width of the maxillary anterior teeth for edentulous patients.

Adult↗
PubMed2002

Computer-based evaluation of gender identification and morphologic classification of tooth face and arch forms.

STATEMENT OF PROBLEM: In prosthodontics, sex-related differences in tooth forms are assumed, and optimal esthetics is further assumed to be achieved only if the face, arch, and tooth forms are in harmony. However, there is no universally accepted rule or mathematical method to define these morphologic features. PURPOSE: The purpose of this study was to evaluate whether anterior tooth from reflected gender and to question the hypothesis that there was a correlation among face, arch, and tooth forms on the basis of dentists' perceptions. MATERIALS AND METHODS: Photographic records including full face, dental arch, and anterior tooth images of 60 dental students were made by use of digital photography. A database was arranged as a questionnaire for evaluation by prosthodontists who were asked to define the sex and morphologic features of the subjects by examining stored images of the subjects. Thirteen prosthodontists, all with at least 10 years of experience, served as experts and performed these evaluations twice at 2-week intervals. Kappa statistic was used to measure intraobserver and interobserver agreement. RESULTS: The average correctly identified values in females and males were 53% and 58%, respectively. However, the proportions of females and males who were identified correctly and completely the same in both the first and second evaluations were 36% for females and 41% for males. According to the observations of the experts, face-to-arch form (54%) and face-to-tooth form (51%) correlations were higher than the tooth-to-arch form correlation. The overall correlation among face, arch, and tooth forms was 31%. The experts were in fair agreement in defining tooth forms. CONCLUSIONS: The results of gender identification of the subjects showed that the experts were unsuccessful in distinguishing the actual sex by the visual assessment of anterior tooth segment alone, with a fair agreement between 2 evaluation sessions. There were also significant interobserver and intraobserver differences in classifying face, arch, and especially tooth forms. Furthermore, the correlation among these forms was not highly defined.

Cephalometry↗
PubMed2005

Anthropoid primates from the Oligocene of Pakistan (Bugti Hills): data on early anthropoid evolution and biogeography.

Asian tarsiid and sivaladapid primates maintained relictual distributions in southern Asia long after the extirpation of their close Holarctic relatives near the Eocene-Oligocene boundary. We report here the discovery of amphipithecid and eosimiid primates from Oligocene coastal deposits in Pakistan that demonstrate that stem anthropoids also survived in southern Asia beyond the climatic deterioration that characterized the Eocene-Oligocene transition. These fossils provide data on temporal and paleobiogeographic aspects of early anthropoid evolution and significantly expand the record of stem anthropoid evolution in the Paleogene of South Asia.

Animals↗
PubMed2005

Additional remains of Wadilemur elegans, a primitive stem galagid from the late Eocene of Egypt.

The late Eocene prosimian Wadilemur elegans from the Jebel Qatrani Formation, northern Egypt, was originally interpreted as an anchomomyin adapiform primate based on limited information from the lower molars and distal premolars. Recently recovered fossils attributable to this species, including a proximal femur, the fourth upper premolar and first and second upper molars, and a mandible preserving the lower second premolar and lower canine and incisor alveoli, reveal a number of derived morphological similarities shared with crown strepsirrhines and, in particular, Miocene-to-Recent stem and crown galagids, to the exclusion of known adapiforms. Phylogenetic analysis of 359 morphological features scored across 95 living and extinct crown primate taxa supports a stem galagid placement for Wadilemur and older Saharagalago, and a close relationship between crown strepsirrhines and the Eocene African taxa "Anchomomys" milleri, Djebelemur, and Plesiopithecus (none of which appear to be closely related to European anchomomyins). This scheme of relationships supports the hypothesis that crown Strepsirrhini is of Afro-Arabian origin and that lemuriforms likely colonized Madagascar by crossing the Mozambique Channel. Wadilemur's known dental and postcranial morphology provides additional support for the hypothesis that galagids and lorisids had diverged by the close of the middle Eocene, and, by bolstering the approximately 37 million-year-old calibration point for crown lorisiform origins provided by Saharagalago, indirect support for the hypothesis of an ancient origin of crown Strepsirrhini and crown Primates.

Animals↗
PubMed2001

The relationship of handedness to asymmetry in the occlusal morphology of first permanent molars.

Handedness has been shown to be related to a number of systematic asymmetries in body dimensions, dermatoglyphic patterns and cerebral morphology. The aim here was to compare linear and angular tooth crown asymmetries of the permanent molars in healthy right-handed and left-handed subjects. The material comprised 27 children with recorded concordant left-side dominance of hand, eye and foot. The controls were an age- and sex-matched group with right side dominance. The material is based on the Collaborative Perinatal Project where detailed medical records and the dentitions, including accurate dental impressions, of over two thousand American children were examined in the USA in the sixties. Machine vision technique was used to obtain accurate three-dimensional information from the occlusal surfaces of the first permanent upper and lower molars. The directional asymmetry values of angular measurements of mandibular first molars showed evidence of asymmetry of opposite direction between the two examined groups. The results indicate that occlusal morphology of first permanent molars may be affected by handedness, and this tendency is most evident in the angular measurements of the mandibular molars. Fluctuating asymmetry did not differ significantly between the examined groups.

Child↗
PubMed2000

Radix mesiolingualis and radix distolingualis in a collection of permanent maxillary molars.

Two lingual root structures are occasionally found on human permanent maxillary molars. One of these is the normal lingual root, which is always present, the other is a supernumerary structure which can be located either mesiolingually (radix mesiolingualis (RML)) or distolingually (radix distolingualis (RDL)). The available literature refers only to the existence and location of RML and RDL Very small materials have, quite simply, hitherto precluded a more detailed description of these roots. The large collection of extracted teeth at the School of Dentistry in Copenhagen now includes a non-random subcollection of 145 permanent maxillary molars, the root complex of which contains 2 lingual root structures. Based on this material it was possible to undertake a modern, systematic analysis of the macromorphological variation of RMLs and RDLs. In this study, which was mainly non-metric, criteria for the identification of RML and RDL were established. The analysis also showed that the lingual supernumerary roots were only rarely found on the first molar, but with increasing frequency on the second and third molars. Both separate and non-separate RML and RDL were observed. In the material, degrees of separation greater than 0.9 were registered, degrees of divergence up to approximately 45 degrees, an apical bend of approximately 90 degrees, and extreme apical slenderness. Even though the supernumerary roots described here do not occur very often, knowing about them is nevertheless clinically relevant in for example endodontic and surgical contexts.

Humans↗
PubMed2002

Prevalence of short-root anomaly in healthy young adults.

Short-root anomaly (SRA), occurring mostly in maxillary incisors, is defined as developmentally very short, blunt dental roots. The condition has a genetic background and is related to hypodontia. Earlier population studies have been based on schoolchildren with developing dentitions and have indicated prevalence figures between 1% and 10%. We studied a random sample of existing panoramic radiographs of 2000 university students for SRA. Roots as long as or shorter than the crowns in the incisors and visually evaluated as very short, blunt roots bilaterally in the posterior teeth were classified as SRA. The prevalence was 1.3%. According to anamnestic information, half the SRA patients had undergone orthodontic therapy, but pre-treatment radiographs were unavailable. In 70% of the SRA patients the short-rooted tooth pairs were upper incisors, but also involved were maxillary premolars, lateral incisors, and lower second premolars. Women were significantly more often affected. We discuss other factors known to cause short-rooted teeth and conclude that the population prevalence for genetic SRA in fully developed dentitions is close to our 1.3%.

Adult↗
PubMed2003

Dental characteristics in Williams syndrome: a clinical and radiographic evaluation.

Williams syndrome is a rare congenital syndrome with distinctive craniofacial features, cardiovascular abnormalities, and behavior characteristics including mental retardation. The dental abnormalities have received scant attention in previous literature. The aim of this study was to describe dental characteristics in individuals with Williams syndrome. In a group of 41 individuals more than 10 years of age, 40.5% had agenesis of one or more permanent teeth and 11.9% had agenesis of 6 permanent teeth or more. The mesio-distal and labio-lingual dimensions of permanent tooth crowns were measured on 31 dental study casts from individuals older than 12 years. The mesio-distal and labio-lingual dimensions were significantly smaller compared with a reference sample. An analysis of tooth morphology was performed on the same dental study casts revealing altered tooth morphology. A high proportion of maxillary and mandibular incisors was tapered or screwdriver shaped. An evaluation of taurodontism on mandibular permanent molars was performed using a metric crown-body/root ratio. However, most of the molars rated as being taurodontic had short or extremely short total tooth lengths and could thus be rated taurodontic without meeting the classical definition. The results of this study indicate that although there is variation in dental development in individuals with Williams syndrome, agenesis of permanent teeth in combination with aberrations in tooth size and morphology may affect dental esthetics and complicate orthodontic and prosthodontic treatment.

Adolescent↗
PubMed2004

Root length in transplanted premolars.

The objectives of the present prospective longitudinal study were to establish the survival and success rates for premolars with partly developed roots transplanted according to a set protocol, and to analyze the effect of varying pre-surgery root development on final root length. Standardized periapical radiographs of 132 consecutively transplanted premolars were obtained at predetermined intervals over a 4-year follow-up period. Survival and success rates were calculated on the basis of presence of teeth and recording of defined radiological variables, respectively. Final root length was compared to normative metric data for root morphology. From the total sample, 54 patients with 68 transplanted premolars suitable for analysis of root growth relative to initial root length were identified, and divided into subsamples according to root length pre-transplantation. Survival rates were 100% after 1, 2, and 3 years, and 98.6% 4 years post-transplantation. The success rates were 92.9%, 92.8%, 89%, and 90.5% in subsamples collected 1, 2, 3, and 4 years after transplantation, respectively. The transplants obtained on average 78% of normative root length, and by dichotomizing the transplanted teeth in subsamples with 'short' and 'long' roots pre-surgery, similar final root lengths were observed even if 'short' roots had the greatest increase. Very early transplantation (roots < 7 mm), however, tended to result in short final root length. It is concluded that the success and survival rates were comparable to results obtained in similar studies. Initial root length was a significant predictor of root length increase. Transplanting teeth with short roots is to risk short final root length.

Bicuspid↗
PubMed2005

Dental arches in six-year-old children with operated and unoperated submucous cleft palate and isolated cleft palate.

The sizes of dental arches in 129 children with cleft palate were evaluated retrospectively from dental casts taken at the mean age 6.2 years (range 5.2-7.5). The material included 61 children with submucous cleft palate (SMCP) and 68 children with isolated cleft palate (ICP). Twenty of the children with SMCP were not operated on, while 41 had had surgical treatment, either palatal repair (n = 16, mean age at operation: 1.6 years, range 0.8-3.9) or pharyngeal flap (VPP) surgery (n = 25, mean age at operation: 4.5 years, range 2.6-6.2). In children with ICP, one-stage hard-palate and soft-palate closure had been done at the mean age of 1.5 years (range 1.0-2.1). Decreased maxillary intermolar widths were seen in children with SMCP after VPP, and especially after palatal repair. The children with ICP had the smallest maxillary dental arch widths. No significant differences were observed in the maxillary arch length or mandibular intermolar arch dimensions in children with SMCP or ICP. Surgery is associated with decreased maxillary intermolar arch widths in children with SMCP. Children with ICP had smaller maxillary dental arch widths than children SMCP.

Child↗
PubMed2005

Mandibular asymmetry in healthy children.

Facial asymmetry is a naturally occurring phenomenon that is often due to differences in the mandibular dimensions on the right and left sides. The point where normal asymmetry turns abnormal cannot be easily defined, and no standards exist by which a judgement of abnormality can be made. The aim of the present study was to assess mandibular asymmetry in healthy children and its possible fluctuation during growth. The subjects consisted of 182 healthy children (88 girls, 94 boys) who had had an orthopantomogram taken at ages 7 (mean 7.5 years) and 16 (mean 15.9 years). On digitized orthopantomograms, condylar and ramus heights on both mandibular sides were measured with a Numonics Accugrid digitizer (Numonics Co., Montgomeryville, Pa., USA) and analysed with X-metrix software (Smart Systems, Turku, Finland). A paired t-test was used to determine the significance of the differences between the sides, and ANOVA to test the significance of the change in asymmetry during growth and between genders. The results revealed a statistically significant difference between the right and left sides in condylar height at age 7 years, in ramus height at both ages, and in the condylar and ramus height at age 16 years. The present study confirms that healthy young subjects generally have a statistically significant mandibular asymmetry, which, however, is only seldom clinically significant. The decision to initiate treatment because of asymmetry has to be carefully considered, since the study further showed that mandibular asymmetry may diminish or appear during growth of healthy subjects.

Adolescent↗
PubMed1999

Dental maturity in children of short stature--a two-year longitudinal study of growth hormone substitution.

The aim of this investigation was to present the 2-year follow-up results of a longitudinal study examining the influence of growth hormone (GH) substitution on dental maturity in healthy children of short stature (height <2 SD). At baseline, the children were divided into a GH-deficient group and a GH non-deficient group, and comparisons were made with healthy controls (height between -2 SD and 2 SD) and between the short stature groups. The GH-substituted group included 24 children (8 F, 16 M) with a mean chronological age of 12.20 +/- 2.40 years, whereas the GH non-substituted group included 19 children (5 F, 14 M) with a mean chronological age of 11.00 +/- 2.40 years. The corresponding age- and sex-matched control groups constituted 48 and 36 children, respectively. The mean dental age in the GH-substituted group was 11.60 +/- 2.70 years, compared to their healthy controls 12.40 +/- 2.60 years (P< 0.05). The dental age for the GH non-substituted children was 10.20 +/- 2.60 years compared to their controls 11.90 +/- 2.60 years (P< 0.001). GH-substituted children show an acceleration in their dental maturity in contrast to controls, whereas in non-substituted children the acceleration is less pronounced.

Adolescent↗
PubMedDate not supplied

Segregation analyses of tooth size in a Melanesian population.

Dental casts and genealogical records collected among several linguistic groups of the Solomon Islands of Bougainville and Malaita form the data-base for the present series of analyses of the human dentition at the population level. Pedigree analysis and complex segregation analysis of nuclear families produce mutually consistent results which are interpreted as the absence of any significant major-gene effect on tooth size.

Female↗