Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Odontometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources
PubMed1990

The morphology of canines in relation to preadjusted appliances.

The canine occupies the transition from anterior to posterior occlusion. Following orthodontic treatment the canine's incisal edge occlusion demonstrates the tip and torque present in the appliance that was used. The effective torque of the bracket, however, is influenced by the tooth morphology at the bracket's base. The morphology of the facial surface can be described by an angle formed between the tangent at the point of bracket placement and the long axis of the crown. In this study, tangent angles at four millimeters and five millimeters from the cusp tip of 100 maxillary and 70 mandibular canines were determined. There was a significant difference between tangent angles at the same location on different canine teeth and also at different locations on the same canine tooth. Proximal collum angles were also measured in this study and there was a significant negative proximal collum angle in maxillary canines and a significant positive proximal collum angle in mandibular canines. The presence of these normal biologic variables will either enhance or minimize the torque supplied by preadjusted appliances, depending on a combination of prescription used and biologic variable present.

Cuspid↗
PubMed1992

The asymmetric extraction decision.

Orthodontic study models, intraoral photographs, radiographs and diagnostic set-up casts of four completed adult cases are presented to show the possibilities of atypical treatment planning to correct specific and unusual malocclusions. The cases presented required asymmetric dental extractions in order to achieve the desired treatment results. Three diagnostic procedures were used to assist in making the final treatment decisions; a Bolton tooth size analysis, a space available/space needed assessment, and a pretreatment diagnostic set-up. The completed treatment results closely approximate the original diagnostic predictions, and completely satisfied each patient's chief concern. Most orthodontic practices now treat increasing numbers of non-growing (adult) patients. Traditional extraction considerations must be modified to satisfy the treatment needs of this demanding patient population.

Adult↗
PubMed1993

Analyses of craniofacial and dental morphology in monozygotic twins discordant for cleft lip and unilateral cleft lip and palate.

The Michigan Cleft Twin Sample data was analyzed in order to investigate dental arch and craniofacial morphology. The present study consisted of 12 monozygotic twins discordant for either cleft lip or unilateral cleft lip and palate. Individuals having CL (repaired) alone did not differ from their unaffected counterparts in dental arch and skeletal morphology. Repaired UCLP subjects were characterized by having a shorter and more posteriorly positioned maxilla. Although reduction of dental arch width as a result of scar contraction following surgery was evident, the effects of scar tissue pull did not affect maxillary basal width.

Cephalometry↗
PubMed1994

Posttreatment changes in different facial types.

The purpose of this study was to describe and compare the changes occurring during and after orthodontic treatment in three facial types: short, average and long. Sixty-six subjects with Class II, Division 1 malocclusion were evaluated. All cases were treated nonextraction, using a fixed edgewise appliance and extraoral forces. The lateral cephalogram and dental casts for each patient were measured at three different stages: pretreatment, immediately after appliance removal and at least two years posttreatment. There was a wide range of individual variation in posttreatment change for the various skeletal and dental parameters measured. With few exceptions, the three facial types did not show significant differences in posttreatment change. The relative protrusion of maxillary incisor tip (U1:A-Pog) tended to increase after treatment in the long face type while it tended to decrease in the short face type. Long face females, when compared with all other groups, showed greater posttreatment incremental increase in anterior face height as well as the greatest posttreatment decrease in maxillary arch length. Males expressed greater posttreatment incremental increases in the various linear measurements of face height than females. Differences in posttreatment change for the different facial types do not require special retention consideration.

Adolescent↗
PubMed1995

Reliability of the Bolton tooth-size analysis when applied to crowded dentitions.

The Bolton tooth-size analysis is widely taught and used in orthodontics. However, its reliability has not been documented. The purpose of this study was to evaluate the reliability of the analysis when performed with needle-pointed dividers and a Boley gauge. Four clinicians measured the teeth on 15 sets of casts with two instruments at two sessions. The measurements were used to calculate tooth-size excess. To evaluate the measurement error, the difference between the two analyses made by the same investigator on the same set of casts was calculated. More of the same-investigator analyses were significantly correlated when the Boley gauge was used than when the needle-pointed dividers were used. Between-investigator analyses revealed significant correlations for each measurement session with both instruments. Every investigator was found to have at least one measurement error for each analysis and with each instrument that was as large as a clinically significant result of a Bolton analysis. The results of this study demonstrate that clinically significant measurement errors can occur when the Bolton tooth-size analysis is performed on casts with at least 3 mm of crowding. The Boley gauge demonstrated a higher frequency of significantly correlated repeated measures and thus may be somewhat more reliable for this analysis than the needle-pointed dividers.

Cuspid↗
PubMed1996

Changes in the dental arches and dentition between 25 and 45 years of age.

The purpose of this longitudinal investigation was to study changes in the dental arches and dentition that occur in midadulthood in an untreated, normal sample. The subjects had Class I molar and canine relationships with less than 4.0 mm of overjet and less than 50% overbite. None had undergone previous orthodontic treatment. Evaluations and measurements were made from dental casts and periapical radiographic surveys of 15 females and 15 males from approximately 25 years to 46 years. The findings indicate that over the span of the study, significant changes occur in the maxillary and mandibular dental arches and dentition in both males and females, including a clinically significant increase in tooth size-arch length (circumference) discrepancy. These changes should be considered part of the normal maturational process and should be taken into consideration when planning treatment and retention options for adolescent and adult patients.

Adult↗
PubMed1998

Class II Division 2 malocclusion: a heritable pattern of small teeth in well-developed jaws.

Angle's designation of the Class II Division 2 (II/2) malocclusion recognizes a unique combination of overbite, incisor retroclination, and sagittal discrepancy. A very severe II/2 phenotype, characterized by concealment of the mandibular incisors in occlusion, has been called Deckbiss in German, or cover-bite. In this report, the cover-bite malocclusion is studied to identify morphological factors associated with Angle's II/2 occlusal discrepancy. Selected X-ray cephalometric and odontometric measurements were recorded for 23 subjects (M14; F9) with II/2 cover-bite malocclusion. Data were compared with those from a control-reference sample of 537 individuals. Cephalometrically, the II/2 cover-bite sample showed a pattern of strong vertical posterior development of the mandible with forward-rotation and skeletofacial hypodivergence (p < 0.0001). Anteroposteriorly, the maxillomandibular dentoalveolar relationship was relatively normal, and the basal bone region of the mandibular corpus appeared significantly well developed anteriorly, accounting for excessive bony chin projection (p < 0.0001). Dentally, mesiodistal tooth diameters for the maxillary and mandibular incisors of the II/2 cover-bite sample were significantly smaller than those of the reference sample (p < 0.002), pointing to systematically reduced tooth-size as a trait associated with II/2 malocclusion. These findings of a characteristic pattern of heritable skeletal and tooth-size features in II/2 cover-bite malocclusion indicate the presence of strong genetic influences in the formation of Angle's II/2 deep-bite discrepancy.

Adolescent↗
PubMed1998

Mixed dentition analysis for Hong Kong Chinese.

Using simple linear regression analyses, prediction equations for the combined mesiodistal crown diameters of canines and premolars based on lower incisor size were generated from 97 Hong Kong Chinese (51 males and 46 females, average age 12.31 years) out of a sample of 112. The mesiodistal crown diameters of the permanent teeth were measured using calipers and recorded to the nearest 0.01 mm. Significant sex differences were found for the combined diameters of the canine-premolar segments. The coefficients of correlation between combined diameters of canines and premolars and lower incisors ranged from 0.65 to 0.79. Significant sex differences of the regression equations were found and thus four simple linear regression equations were generated. Coefficients for the slope ranged from 0.58 to 0.66, and coefficients for the intercept ranged from 6.66 to 8.82. The R2 values, standard errors of estimate, and absolute mean errors revealed that prediction models for females were less precise than those for males. Probability tables were constructed from the results of the present study. The prediction equations were found to differ from those of Tanaka and Johnston. Accuracy in the mixed dentition analysis for southern Chinese would be improved by applying the prediction equations or probability tables generated from the present study.

Asian People↗
PubMed1998

The use of tooth thickness in predicting intermaxillary tooth-size discrepancies.

Intermaxillary tooth-size discrepancies can be assessed using a diagnostic setup or predicted using a mathematical formula, such as the Bolton analysis. However, variations in tooth thickness may produce inaccuracies in the Bolton analysis ratio. To date, no method for incorporating tooth thickness into discrepancy prediction has been proposed. The purpose of this study was to design and test a new method of predicting anterior tooth-size discrepancy that takes into account tooth thickness and width. Forty-four positioner setup models were set to ideal overbite (2.5 mm) and occlusion (Class I canine relationship). Interproximal gaps between the maxillary or mandibular central incisors were allowed in order to optimize tip and torque. The mesiodistal width of all anterior teeth and the labiolingual thickness of the maxillary incisors were measured on these idealized setups to the nearest 0.1 mm. Actual intermaxillary anterior ratios were then calculated. A new method of prediction was developed by assuming a linear relationship between tooth thickness and ideal intermaxillary ratio. Errors in Bolton's method were compared with the new method. The results showed wide variations in mesiodistal tooth widths, tooth thicknesses, and intermaxillary anterior ratios in orthodontically treated patients. The correlation coefficient between the intermaxillary ratio and tooth thickness was r = 0.68 when tooth thickness was < 2.75 mm, and r = 0.28 when tooth thickness was > or = 2.75 mm. The mean absolute errors in predicting the actual intermaxillary ideal ratio was 1.29 +/- 0.81 for Bolton's ratio and 0.84 +/- 0.46 for the new prediction formula. These new formulas were better than Bolton's ratio in predicting tooth-size discrepancies (p = 0.003). Tooth thickness combined with mesiodistal width may be useful in predicting intermaxillary tooth-size discrepancies.

Algorithms↗
PubMed1998

Ectopic eruption of the first permanent molars: prevalence and etiologic factors.

The purpose of this research was to study the prevalence of ectopic eruption of the first permanent molars and possible etiologic factors. A group of 4,232 Thai students, from 6 to 9 years old, was examined. The prevalence of ectopic eruption of the first permanent molars in the subjects was 0.75%. Both the severity of the ectopic eruption and the amount of root resorption on the second primary molars were more pronounced in the maxilla than in the mandible. The important etiologic factors were the eruption path of the first permanent molars relative to reference lines and the size of the mandibular second primary molars. The amount of proximal caries did not seem to affect the prevalence of ectopic eruption.

Analysis of Variance↗
PubMed1999

Molarization of the lower second premolars.

This paper presents a case of extreme tooth variation. The patient was first observed during the mixed dentition period, when she presented a mild Class II malocclusion with increased overjet and acceptable overbite. In a panoramic radiograph, the presence of lower second premolars of disproportionate dimensions was discovered. When these oversized premolars erupted, the Class I malocclusion tended toward Class III, with an edge-to-edge bite. This created an unstable occlusion and the possible need for extractions.

Bicuspid↗
PubMed2000

Tooth-size reduction associated with occurrence of palatal displacement of canines.

This study investigates mesiodistal crown size of the maxillary and mandibular incisors of patients with palatally displaced canines (PDC). Pretreatment dental casts of orthodontic patients with PDC of 1 or both maxillary canines (N = 31; M10:F21) were collected. This PDC sample was matched according to age and sex with pretreatment dental casts from unaffected orthodontic patients. For the PDC and matched control samples, maximum mesiodistal crown diameters were recorded for the 4 incisors on the left side only. The results showed that, on average, the mesiodistal crown diameters for the maxillary and mandibular incisors measured smaller in the PDC sample than in the control sample. These findings of statistically significant tooth-size reductions associated with PDC occurrence indicate a generalized pattern of reduced tooth size as a characteristic associated with the PDC anomaly. Further, the presence of generalized tooth-size reduction in cases with palatally displaced canines helps explain why most orthodontic treatment plans for PDC patients are of the nonextraction type.

Adolescent↗
PubMed2000

Maxillary arch size and shape in American blacks and whites.

American blacks have larger teeth than whites, but they less frequently exhibit crowding--apparently because of larger arch dimensions. This study quantified differences in arch size and shape in these 2 constituents of the US population. Eighteen dental and bony landmarks were digitized from the maxilla of each of 332 subjects with permanent, intact dentitions, proportionately divided between blacks and whites, men and women. Linear, angular, and area measurements were computer-generated. Arch widths averaged 10% greater in blacks than whites, and mesiodistal arch depths had a greater difference, at 12%. Blacks, with a more square palate and significantly larger palatal index, were distinguished from whites primarily by greater intercanine and interpremolar widths. Arch perimeter was greater in blacks by 8%, and cross-sectional area of the arch was 19% greater in blacks than whites, so blacks and whites differ substantially for these parameters not only in size, but in shape as well. These differences are relevant in prosthodontics and orthodontics since individualization of treatment leads to more effective treatment by working within the patient's natural arch form instead of making patients fit a single standard.

Adult↗
PubMed2000

Mesiodistal crown dimensions and tooth size discrepancy of the permanent dentition of Dominican Americans.

The purpose of the study was to establish normative data on the mesiodistal crown dimensions of Americans of Dominican background. The Bolton tooth size analysis was performed on a sample of 54 Dominican Americans. The mean, range and standard deviation were calculated for the size of the teeth, and a coefficient of variation was obtained for the tooth size ratio. A 2-sample t-test was used to test for the statistical difference between means. In general, the values obtained for the Dominican American sample closely resembled previous data available for the African American population. The tooth size ratios obtained were compared to the Bolton ratios. The overall ratio was found to be 91.3, equivalent to the Bolton overall ratio, whereas the anterior ratio was 78.1, larger than the 77.1 Bolton ratio. The frequency of tooth size discrepancy outside 2 standard deviations from the Bolton mean was also calculated. An overall tooth size discrepancy was found in 11% of our sample, and 28% of the sample presented an anterior tooth size discrepancy.

Adult↗
PubMed2001

Anterior space relations and lower incisor alignment in 9-year-old children born in the 1960s and 1980s.

The anterior arch spaces and the effect of early loss of deciduous canines have been studied in 2 different cohorts of 9-year-old children. One group of 119 children was from Norway and consisted of 56 girls and 63 boys, and 1 group of 133 children was from Sweden and consisted of 72 girls and 61 boys. Within these cohorts, half of the children were born in the 1960s and half in the 1980s. The 1960s group has been compared with the 1980s group to look for anterior arch changes occurring during this period of time. The children who had lost a lost deciduous canine at the age of 9 years were also compared with the children with all deciduous canines remaining. Groups were compared with analysis of variance. It was found that children with a lost deciduous canine at the age of 9 years belong to a group with less available arch space and are a crowded group when compared with an earlier study. For the girls, this was also associated with larger teeth. Anterior arch space did not differ between the 1960s and the 1980s groups except for the Swedish boys, where there was less available mandibular arch space in the 1980s group. The irregularity index for the 4 mandibular incisors was increased in the 1980s group compared with the 1960s group. This could indicate a secular trend toward an increased prevalence of malocclusion in the present population.

Analysis of Variance↗
PubMed2001

Three-dimensional inclination of the dental axes in healthy permanent dentitions--A cross-sectional study in a normal population.

The 3-dimensional (3-D) inclination of the facial axis of the clinical crown (FACC) and the size of the clinical crowns were measured in 100 white northern Italians. The subjects consisted of 22 girls and 21 boys, ages 13-15 years (adolescents), and 31 women and 26 men, ages 16-26 years (adults), all with a complete permanent dentition and Class I dental relationships. The 3-D coordinates of dental landmarks were obtained with a computerized electromagnetic digitizer. Clinical crowns heights and FACC inclinations in the anatomical frontal and sagittal planes relative to 2 reference planes, maxillary and mandibular (between the incisive papilla and the intersection of the palatal/lingual sulci of the first permanent molars with the gingival margin), were calculated. Ages and sexes were compared by ANOVA. On average, the frontal plane FACCs of most teeth converged toward the midline plane of symmetry. In contrast, the incisors diverged from the midline plane or were nearly vertical. Within each quadrant, the inclinations of the postincisor teeth progressively increased. In the sagittal plane, most teeth had a nearly vertical FACC. FACC inclinations showed sex- and age-related differences (P < .05). In the frontal plane, the canines, premolars, and molars were more inclined in adolescents than in adults. In the sagittal plane, a large within-group variability was observed. Clinical crown height was significantly larger in males than in females in all maxillary and mandibular canines, premolars, second molars, maxillary central incisors, and first molars. With age, some degree of dental eruption was found in maxillary and mandibular canines, maxillary second premolars, and molars. The age-related decrease in FACC inclination may be the effect of a progressive buccal and mesial drift.

Adolescent↗
PubMed2001

Treatment timing for rapid maxillary expansion.

The aim of this study was to evaluate the short-term and long-term treatment effects of rapid maxillary expansion in 2 groups of subjects treated with the Haas appliance. Treatment outcomes were evaluated before and after the peak in skeletal maturation, as assessed by the cervical vertebral maturation (CVM) method, in a sample of 42 patients compared to a control sample of 20 subjects. Posteroanterior cephalograms were analyzed for the treated subjects at T1 (pretreatment), T2 (immediate post-expansion) and T3 (long-term observation), and were available at T1 and at T3 for the controls. The mean age (years: months) at T1 was 11:10 for both the treated and the control groups. The mean ages at T3 also were comparable (20:6 for the treated group and 17:8 for the controls). Following expansion and retention (2 months on average), fixed standard edgewise appliances were placed. The study included transverse measurements on dentoalveolar structures, maxillary and mandibular bases and other craniofacial regions (nasal, zygomatic, orbital, and cranial). Treated and control samples were divided into 2 groups according to individual skeletal maturation. The early-treated and early-control groups had not reached the pubertal peak in skeletal growth velocity at T1 (CVM 1 to 3), whereas the late-treated and late-control groups were during or slightly after the peak at T1 (CVM 4 to 6). The group treated before the pubertal peak showed significantly greater short-term increases in the width of the nasal cavities. In the long-term, maxillary skeletal width, maxillary intermolar width, lateronasal width, and lateroorbitale width were significantly greater in the early-treated group. The late-treated group exhibited significant increases in lateronasal width and in maxillary and mandibular intermolar widths. Rapid Maxillary Expansion treatment before the peak in skeletal growth velocity is able to induce more pronounced transverse craniofacial changes at the skeletal level.

Adolescent↗