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 199 records · Page 11Linked to original sources
PubMed1980

Changes in the vertical position of the anterior teeth after surgical correction of mandibular protrusion.

A group of patients who had undergone an oblique vertical ramus osteotomy for correction of mandibular protrusion was examined 2 years postoperatively in order to clarify whether the treatment resulted in vertical changes of the front teeth. 1. The results indicate an extrusion of both the upper and lower anterior teeth, as the distance from the upper and lower incisors to the NL and ML lines increased postoperatively (0.3 to 2.3 mm.). 2. The clinical crown height increased (0.3 to 0.4 mm.). 3. The root length decreased (0.5 to 0.9 mm.). 4. There were only insignificant changes in the height of the interproximal marginal bone. 5. There was no significant correlation between the changes in crown height and the amount of tooth extrusion; nor was there any correlation between these changes and the changes in mandibular inclination or root length reduction.

Adolescent↗
PubMed1980

Segment concept in arch pattern design.

The forming of arch wires is time consuming and often relies more on artistic interpolation than on scientific method, thus making the basis of orthodontic practice less precise. For years, various methods of designing arch wires have been tried and have been found inadequate. A new approach is advocated. Based on two decades of orthodontic practice and research, it elucidates a segment concept of arch pattern design, using three common reference measurements of the mandibular arch: canine width, molar width, and the sum of the mesiodistal diameters of the six mandibular anterior teeth. Normative data accumulated from 555 dental patients standardize basic measurements and variants. These data permit development of a finite number of arch patterns, adaptable to virtually all patients. A pattern, once selected, may be used as is or individualized to a specific arch form if necessary. Use of the segment concept might permit a much higher degree of clinical efficacy than that obtained with other methods of arch-wire construction.

Adolescent↗
PubMed1980

A revision of the Hixon and Oldfather mixed-dentition prediction method.

A revision of the Hixon and Oldfather prediction method was undertaken with measurements obtained from persons who participated in the Iowa Facial Growth Study, the same group of subjects used originally by Hixon and Oldfather to develop their prediction equation. A significantly improved prediction equation was developed. A graph was made for clinical use in the prediction of mandibular canine and premolar widths in mixed-dentition patients.

Bicuspid↗
PubMed1981

A biometric study of tooth size and dental crowding.

A study was conducted for the purpose of comparing mesiodistal tooth widths between a group of patients with good tooth alignment and a group of patients with crowded dental arches. Crowded arches were defined as those with more than 4 mm. of space deficiency. The hypothesis tested was whether the arches with more than 4 mm. of crowding consistently had larger teeth than the ones with lesser or no crowding. The difference in sizes between the groups (forty males and forty females) for all teeth measured was found to be statistically significant (p less than 0.001). The multivariate data analysis indicated that the two groups were derived from two different populations and that the maxillary lateral incisors and second premolars and the mandibular canines and premolars were particularly different in these groups. It was also determined that the teeth in males were uniformly larger than in females, but not to a statistically significant level. There was less correlation, however, between the sex and the status of the tooth alignment in dental arches, so that both sexes had similar distribution of crowding versus noncrowding. On the basis of this study of eighty North American Caucasians, it is suggested that one should consider the sum of mesiodistal widths of teeth, in addition to the arch length analysis, in formulating an orthodontic treatment plan. When the cumulative tooth mass of the twenty permanent teeth is 140 mm. or more, the clinician may want to consider extraction therapy for such a case.

Adolescent↗
PubMed1981

Reliability and validity of lower third molar space-assessment techniques.

Present techniques for predicting eruption or impaction of lower third molars are based on measurements of the space between the second molar and the ramus. This study was designed to investigate the reliability and validity of radiographic techniques often used for assessing this space. Rotational tomograms (O.P.G.s) yielded the best estimates of the Space Width Ratio (found by dividing the space available by the mesiodistal width of the lower third molar) as measured directly on dried skulls. Estimates for lateral cephalograms were unreliable. The use of Xi point to lower second molar for assessing the space for lower third molars is not supported.

Adult↗
PubMed1981

A radiographic study of dental eruption.

The process of eruption of five mandibular teeth was studied radiographically on the annual cephalograms of fifty-four boys and forty-one girls from the ages of 3 to 14 years. It was found that following completion of the crown the teeth moved toward the occlusal plane at a uniform rate until the preocclusal eruption surge of 4 to 7 mm. per year. It was also found that the rapid eruption phase does not correlate with root length increase in which eruption exceeded root growth by as much as 4.6 mm. per year. A significant eruption rate was demonstrated at age 14; the mandibular second molar continued to erupt at approximately three times the rate of the mandibular canines. this suggested rotation of the occlusal plane in relation to the mandibular tangent.

Adolescent↗
PubMed1981

Orthodontic-restorative treatment for relative mandibular anterior excess tooth-size problems.

The diagnostic and conventional treatment techniques used to resolve relative mandibular anterior excess tooth-size problems are reviewed. An alternative solution to these problems, which involves an orthodontic-restorative technique, is described. Specific problems which may be encountered with this technique are also discussed. Three cases are presented, with posttreatment documentation for at least one year. It appears that this technique offers a successful semipermanent treatment for selected cases.

Adolescent↗
PubMed1982

Incisor shape and incisor crowding: a re-evaluation of the Peck and Peck ratio.

Although lower incisor tooth shapes, defined as mesiodistal length divided by labiolingual width, have bee proposed as important factors in lower incisor crowding, the question of whether or not these ratios are more useful than simple measurements of incisor mesiodistal length has not been addressed. In order to test this question, we measured mesiodistal and labiolingual incisor dimensions and lower incisor crowding (defined as the crowding index proposed by Little) on dental casts from two groups: 100 pretreatment orthodontic patients and 100 Hutterites from a religious isolate in Canada. The orthodontic patients are our primary interest. The Hutterites serve mainly to test whether or not results are consistent in another population of different ethnicity, age distribution, and occlusal status. In each population, incisor crowding is correlated with the tooth shape ratios, confirming the general observations of Peck and Peck. However, mesiodistal incisor lengths have slightly higher correlations with crowding than the shape ratios. In multiple regression equations to predict crowding in each population, incisor mesiodistal lengths are the most important variable, and neither the tooth shape ratios nor labiolingual widths significantly improve the equations. Although statistically significant, none of the correlations is higher than 0.30, and they are thus of little clinical value. The use of tooth size measurements or ratios as a guide to clinical procedures is an oversimplification of a complex problem.

Canada↗
PubMed1983

The effect of extraction and orthodontic treatment on dentoalveolar support.

Full-mouth radiographs of ninety-six patients treated by extraction of four first premolars were taken at least 10 years postextraction. Three groups were established: one with extensive crowding in the full permanent dentition treated by extraction and fixed appliance therapy; one treated by serial extraction and fixed appliance therapy; and one treated by serial extraction only. Measurements of tooth length and alveolar bone height were made from the projected radiographs, and buccolingual socket areas were measured from direct tracings of the radiographs. Comparison between groups revealed reduced mean radiographic tooth lengths for incisors and mandibular molars in the orthodontically treated groups. The incidence of root resorption was similar for both treated groups. Reduced alveolar bone heights were noted in the extraction sites of the two orthodontically treated groups but not in the group treated by serial extraction only. Most reduction in long-term dentoalveolar support occurred as a result of root resorption except in the extraction sites, where it occurred largely as a result of bone loss. Root parallelism did not appear to influence proximal bone heights at the extraction site. In malocclusions involving arch length deficiency, maximally displaced canines had reduced long-term proximal bone compared to nondisplaced canines, supporting the concept of encouraging autonomous distal eruption through serial extraction.

Adult↗
PubMed1983

An examination of dental crowding and its relationship to tooth size and arch dimension.

This investigation was undertaken to examine the extent to which tooth size and jaw size each contribute to dental crowding. Two groups of dental casts were selected on the basis of dental crowding. One group, consisting of 50 pairs of dental casts (18 males and 32 females), exhibited gross dental crowding. A second group, consisting of 54 pairs of dental casts (24 males and 30 females), exhibited little or no crowding. Means and standard deviations of the following parameters were used to compare the two groups: individual and collective mesiodistal tooth diameters, dental arch perimeters, and buccal and lingual dental arch widths. Statistically, the crowded and noncrowded groups could not be distinguished from each other on the basis of mesiodistal tooth diameters. However, significant differences were observed between the dental arch dimensions of the two groups. The crowded group was found to have smaller dental arch dimensions than the noncrowded group. The results of this study suggest that consideration be given to those treatment techniques which increase dental arch length rather than reduce tooth mass.

Adolescent↗
PubMed1983

Influence of tooth-to-denture-base discrepancy on space closure following premature loss of deciduous teeth.

Influence of tooth-to-denture-base discrepancy on so-called physiologic migration of the first molar was studied on serial dental casts of 116 boys and girls, obtained through a dental health program for school children in an area in which there was no dentist. The alteration of spaces following premature loss of deciduous molars was examined comparing the anterior to posterior discrepancies between tooth and denture base. Modes of space alteration showed positive correlation with the size of the discrepancy, especially in the mandibular dental arches. The space deficiency in the posterior region seemed to have a positive effect on the mesial migration of the first molar. Mesial migration of the first molar seems to be pathologic rather than physiologic and is strongly affected by tooth-to-denture-base discrepancies. Space maintenance does not seem to be useful, because it is not necessary in minimum discrepancy cases and is not effective in severe discrepancy cases.

Adolescent↗
PubMed1984

Reliability of an intraoral camera: utility for clinical dentistry and research.

Photographic images can be reliable and efficient sources of data in dentistry. Many variables can be investigated from single exposures. This study was undertaken to test the reliability of an intraoral graphic instrument--the Orthoscan camera. The utility of this instrument in clinical orthodontics has been described, but the research potential has yet to be investigated. Upper and lower dental arches of fifteen patients were photographed intraorally. Alginate impressions of the arches were taken immediately afterward. Identical intertooth distances were located (1) on the intraoral photographs, (2) on the photographs of the dental casts, and (3) on the dental casts themselves. Univariate and multivariate analyses were used to assess measurement error in these replicate measurements. The camera was found to be a highly reliable instrument. The images are flat and free of distortion, with a one-to-one size relationship. The camera is quite suitable for precise scientific investigations, and the data are acceptable for valid interobserver and interpopulation comparisons.

Cephalometry↗
PubMed1984

Tooth morphology and lower incisor alignment many years after orthodontic therapy.

The dental models of seventy-seven orthodontically treated patients were evaluated to determine the contribution of lower incisor tooth dimensions to their alignment many years after treatment. Tooth dimensions included the maximum mesiodistal (MD) and faciolingual (FL) dimensions and the shape ratio represented by MD/FL. Incisor alignment was assessed by means of Little's irregularity index, and all measurements were recorded to the nearest 0.1 mm with modified dial calipers. Multiple regression analysis revealed that the total contribution of all these lower incisor dimensions accounted for only 7.4% of the variability in their alignment, which was not statistically significant. A similar lack of association between lower incisor tooth dimensions and their alignment was found in a sample of eighty-six adults with untreated malocclusions. It therefore appears that the size and shape of the lower incisors do not significantly contribute to their alignment many years after orthodontic treatment.

Adult↗
PubMed1984

Variability in three morphologic features of the permanent maxillary central incisor.

Variability in tooth morphology can play a significant role in appliance design and the achievable results of orthodontic treatment. This investigation was undertaken to determine quantitatively the variation in three anatomic features of the maxillary central incisor. The three features are the crown-root angulation in a labiolingual direction, the angle formed by a tangent to the middle of the labial surface of the crown and the long axis of the crown from a proximal view, and the lingual curvature of the crown from a proximal view. Tracings of maxillary central incisors were made from two different sources. The first source consisted of radiograms of 98 extracted central incisors, and the second source was a group of 100 cephalometric radiograms which were part of pretreatment records of patients in the Orthodontic Department. The cephalometric radiograms included 25 Angle Class I, 25 Class II, Division 1, 25 Class II, Division 2, and 25 Class III malocclusions. The first measurement taken was the angle formed by the long axis of the crown and the long axis of the root. The second measurement was the angle formed by the long axis of the crown and a tangent to the midpoint of the labial surface of the crown. For the third measurement, the lingual curvature of the crown was described by a mathematical equation whose parameters were used for comparisons. The results revealed a wide range of variation in the three features measured. The mean crown-root angle for Class II, Division 2 malocclusions differed significantly from that for Class II, Division 1 and Class III malocclusions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalometry↗
PubMed1984

Longitudinal study of three views of mandibular third molar eruption in males.

A longitudinal study, using three views simultaneously, was conducted on twenty North American black males to investigate mandibular third molar eruption. Each subject had two third molars present. Forty third molars were studied. Lateral, posteroanterior, and oblique (45 degrees left and right) cephalograms, along with plaster casts, were used. The following observations on the third molars were made; the age at which they can be identified; angulation of the occlusal surface; eruptive path, including the vertical, anteroposterior, and buccolingual positions; and the age of delineation between being unerupted or impacted, including factors related thereto. The Fisher's exact test from the SPSS package and the central tendency were the statistical instruments used to aid in interpreting the data. In some persons the crypt of the developing third molar was seen as early as 7.5 years and the occlusal surface was identified as early as age 8 years, with a mean of 9.75 years. Third molars usually form in the ramus with the distal cusp above the occlusal plane, the occlusal surface of the molar has a great cant facing anteriorly, the tooth descends below the occlusal plane, and appears to upright around 14 to 16 years of age. The impaction of the mandibular third molar is a complex multifactorial mechanism. The wide buccal location of mandibular third molars and the inadequate anteroposterior space between the distal surface of the second molar and the anterior surface of the ramus are important factors in third molar impaction. This study does not support the concept of early prediction of third molar impaction and enucleation of the asymptomatic developing third molars. If possible, the final decision for extraction of asymptomatic mandibular third molars that appear to be impacted should be delayed until after the age of 16 years.

Adolescent↗
PubMed1985

Bilateral congenital absence of maxillary lateral incisors: a craniofacial and dental cast analysis.

The dental casts and cephalometric records of forty-three patients exhibiting bilateral congenital absence of maxillary lateral incisors were evaluated to determine the nature and extent of any concurrent craniofacial and dental anomalies. The effects of bilateral orthodontic space closure were evaluated on a subsample of twenty-two cases. The data revealed normal dental arch length, arch width, overjet, and overbite, while significant tooth size discrepancies were found in several anterior and posterior teeth. Craniofacial deviations from normal included smaller maxillary length, smaller mandibular length, smaller anterior cranial base, and nasal bone. Vertical facial dimensions, both anterior and posterior, were significantly less, as was the mandibular plane angle. Soft-tissue examination revealed a 10 degrees greater nasiolabial angle, which was increased a further 5 degrees as a result of a mean incisor retraction of 1.5 mm during space closure. The craniofacial anomalies noted in the present sample were similar to those seen in persons with clefts and may reflect a common etiology related to a developmental disturbance during fusion of the facial processes in utero. In the treatment of patients with bilateral congenital absence of maxillary incisors, mechanotherapy designed to open the mandibular plane, increase the vertical dimension, and move the maxillary posterior teeth forward is recommended in order to prevent worsening the Class III tendency and to minimize maxillary incisor and upper lip retraction. Most cases will require significant mesiodistal reduction in tooth size in order to achieve an optimal occlusion.

Adolescent↗
PubMed1985

Dentofacial relationships in persons with unoperated clefts: comparisons between three cleft types.

A total of thirty persons with unoperated unilateral cleft lip and alveolus, unilateral cleft lip and palate, and bilateral cleft lip and palate were evaluated. The ages of these persons ranged from 7 to 50 years. Fifty parameters were measured on the cephalograms and the dental casts. Descriptive statistics for these parameters were calculated. The analysis of variance (general linear models procedure) was performed to compare the three cleft groups. Among the significant differences between the cleft groups was an increased steepness of the mandibular plane in persons with palatal clefts. In addition, the persons with bilateral cleft lip and palate had a significant reduction in maxillary intercanine width. A description of the different dentofacial relationships of the different cleft types was also presented. From the findings of the present and previous investigations, it could be surmised that there are differences in the dentofacial relationships of persons with different cleft types. These differences need to be recognized, since they can influence both our understanding of the effects of the surgical repair of the lip and/or palate and the orthodontic management of these cases. The present findings in this relatively limited group of persons indicates that there is still a need to examine in detail a larger number of persons with untreated clefts of the lip and/or palate and to compare them with surgically treated persons from the same population if possible.

Adolescent↗