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 1,171 records · Page 65Linked to original sources
PubMed1981

Clinical crown length in 9-, 11- and 13-year-old children with and without finger-sucking habit.

Continuing finger-sucking often leads to an anterior open bite. The object of the present study was to attempt to illustrate whether this open bite is caused by an arrested eruption of incisors or primarily by inhibited growth of the alveolar processes. A comparison is made between 9-, 11- and 13-year-old children with continuing finger-sucking habits or who ceased finger-sucking only after 8 years of age, and children of the same ages without sucking habits in respect of the clinical crown length of central and lateral incisors in the upper and lower jaws. In all measurements the clinical crown length among children in the finger-sucking groups was greater than among children in the control groups (Table 1). The anterior open bite of the finger-suckers was therefore probably not caused by arrested eruption of incisors but rather by inhibited vertical growth of the anterior part of the alveolar processes.

Adolescent↗
PubMed1992

Measurements of tooth length in panoramic radiographs. 1. The use of indicators.

The aim of this study was to investigate both the actual and the radiographic tooth lengths of the maxillary first molar and second premolar and the mandibular premolars in panoramic radiographs. The actual length of 64 extracted teeth was measured. Steel balls were then attached to the cusp and apex and the teeth embedded in plastic moulds. Each pair of plaster casts with their set of teeth was radiographed with an Orthopantomograph twice at an interval of 1 month. The actual and the radiographic tooth length was measured twice by one observer. The mean tooth length of the molar was shorter than that of the premolars. The mean difference between the repeated measurements of the actual tooth length was small and ranged between 0.47 and 1.16% of the tooth length. The mean difference between repeated measurements of the radiographic tooth length was also small, with a method error of 0.13-0.21 mm. The vertical magnification in panoramic radiography was lower for mandibular premolars (13-15%) than for the maxillary second premolar and first molar (17-28%). The palatal root of the maxillary first molar had the highest vertical magnification (28%). Following the second set of radiographs, the mean difference between the measurements was small, except for the palatal root of the maxillary first molar (P < 0.001). Radiographic measurements of this root should therefore be used with caution. The results for the other roots examined indicate that these could be measured with high reproducibility.

Humans↗
PubMed1992

Measurements of tooth length in panoramic radiographs. 2: Observer performance.

Observer performance in tooth-length measurements in panoramic radiography has been examined. Sixty-four teeth, evenly distributed between maxillary first molars, second premolars and mandibular first and second premolars, were fixed in plastic moulds. Each cast was radiographed with an Orthopantomograph, twice with steel balls indicating the cusps and apices of the teeth and once without them. One observer measured the radiographic tooth length twice in both radiographs with indicators in order to estimate the true radiographic tooth length and the repositioning error, and twice in the radiographs without indicators. Seven other observers measured the tooth length on the radiographs without indicators, twice applying their own criteria and twice using defined criteria. The accuracy of the tooth-length measurements was calculated by comparing the true radiographic tooth length with the measurements of the seven observers. The intra-observer variation was defined as the difference between two measurements on the same radiograph. The accuracy and the precision of the tooth-length measurements were highly influenced by the observer performance. The mean radiographic tooth length of the seven observers was closer to the true radiographic tooth length when the observers applied the defined criteria. The inter- and intra-observer variation was higher for the measurements of the maxillary teeth (0.3-1.9 mm) compared with the mandibular teeth (0.3-0.9 mm) for most observers. The highest intra-observer variation was found for the palatal root of the maxillary first molar. The intra-observer variation of four observers decreased somewhat when the defined criteria were used; for the other three observers, however, the variation increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1996

Methods of reducing observer variation in age estimation from panoramic radiographs.

OBJECTIVE: To compare inter- and intra-observer variation in age estimation using subjective and objective methods. METHODS: Fifty-six panoramic radiographs of patients aged 13 to 25 years were assessed subjectively twice by four observers for the stage of root development of the lower third molars on a seven-point scale. Two of the observers were calibrated before the first evaluation, and the other two before the second. The same observers also digitized predefined reference points in a subsample of the third molars ten times by means of a computer-based digitizer system. Observer variation in classifying different root stages and in digitizing coordinates and measuring root lengths were studied. RESULTS: Significant systematic differences existed between two of the observers in the subjective assessment. One non-pre-calibrated observer changed her pattern most. Scattergrams from the digitizer measurements showed a good precision within and between observers with no significant differences in calculating root lengths. When, however, the teeth were analysed separately, some significant differences were found. CONCLUSIONS: The overall observer agreement was best using the objective method on several teeth. With only one tooth there were some significant differences. Subjective evaluation was improved by prior calibration.

Adolescent↗
PubMed2004

Estimation of single-root surface area from true thickness data and from thickness derived from digital dental radiography.

OBJECTIVES: The prognosis of a tooth affected by periodontitis may depend on the amount of bone remaining around the root surface. The aim of this study was to find how the surface area of a single root is related to the true thickness data and the calculated thickness data from digital dental radiographs. METHODS: Eight extracted single-root teeth were digitized three-dimensionally for direct surface area measurement. Meanwhile, they were also exposed to a digital dental X-ray system. The true thickness of the tooth root was measured. The estimated circumference data were calculated from both the measured thickness and the thickness estimated from the digital image and then measured and estimated circumferences were compared. RESULTS: (1) The largest circumference difference mean for measured thickness and for estimated thickness was -4.94% (+/-0.07%) and 23.02% (+/-1.12%) respectively. (2) The largest 95% confidence interval for difference means for measured thickness and for estimated thickness was (-2.82%, -1.87%) and (-5.42%, 2.22%), respectively. CONCLUSIONS: When the thickness data are available, the surface area of a single-root tooth can be estimated to an error of less than 5%. Theoretically, the root thickness can be derived from the projected radiological image of the tooth. However, the error of estimated circumference from digital dental radiography may be over 20%. This error can be minimized if the estimated thickness from digital dental radiography can be made more accurate.

Absorptiometry, Photon↗
PubMed2005

Clinical evaluation of the effects of radiographic distortion on the position and classification of mandibular third molars.

OBJECTIVE: Panoramic radiographs are routinely employed for surgical planning of unerupted third molars. The objective of this study was to evaluate distortions in the position of mandibular third molars on panoramic radiographs. MATERIALS AND METHODS: Panoramic radiographs of 14 patients with indication for extraction of the mandibular third molars were used. Transurgical impressions of the crowns of the teeth to be extracted and adjacent second molars (n=19) were achieved with addition silicone and poured with type IV plaster for comparison of the inclinations of the third molars on the radiographs and study casts. RESULTS: There was a mean difference of -5.37 degrees between the position of the third molar on the panoramic radiograph and on the study cast (standard deviation 1.46, P<0.05, Student's t-test). CONCLUSION: There is distortion in the position of teeth on the panoramic radiograph, which may influence the surgical planning; however, this does not invalidate it as the main tool for diagnosis and surgical planning of mandibular third molars.

Artifacts↗
PubMed2004

Prediction of premolar tooth lengths based on their panoramic radiographic lengths.

OBJECTIVE: Establishing a linear regression model for the determination of first premolar lengths based on panoramic radiographs. MATERIALS AND METHODS: The real lengths of 112 first premolars extracted for orthodontic reasons were measured and compared with their panoramic lengths. The teeth were divided into four groups according to their intraoral quadrant locations (T14, T24, T34, T44) and regression analysis was conducted for each group. RESULTS: A linear regression model for the prediction of tooth length (mm) based on the panoramic length was established (P < 0.0001): For group T14 the predicted length = (panoramic length x 0.698) + 2.61. For group T24 the predicted length = (panoramic length x 0.5056) + 7.844. For group T34 the predicted length = (panoramic length x 0.5075) + 9.282. For group T44 the predicted length = (panoramic length x 0.436) + 11.298. CONCLUSION: Prediction of all first premolar lengths using their panoramic images is both feasible and reliable.

Adolescent↗
PubMed2006

Radiographic features of the jaws and teeth in thalassaemia major.

OBJECTIVES: This investigation aimed to compare the radiographic changes and root and crown-body lengths of the mandibular first permanent molar in a group of thalassaemic patients with a control group, matched for age and sex. METHODS: Panoramic radiographs of 50 thalassaemic patients and 50 controls were examined for the presence of radiological changes. Crown body and root lengths were determined using the method of Seow and Lai. The average lengths were calculated and compared between the two groups. RESULTS: The mean crown-body and root lengths of the mandibular first molar of patients with thalassaemia major were 9.58+/-0.83 mm and 11.89+/-1.33 mm, while those for the control group were 10.45+/-0.78 mm and 12.78+/-1.67 mm, respectively. A significant difference (P<0.05) was found between the mean crown-body and root values of the two groups. A significant difference (P<0.05) was also found between thalassaemic patients and controls in the occurrence of spiky-shaped roots, root and crown lengths, taurodontism, attenuated lamina dura, enlarged bone marrow spaces, small maxillary sinuses, faint inferior alveolar canal and thin cortex of the mandible. CONCLUSIONS: While thalassaemia major may not be associated with the occurrence of either vascular canals or prominent antegonial notch, spiky-shaped and short roots, taurodonts, attenuated lamina dura, enlarged bone marrow spaces, small maxillary sinuses, absence of inferior alveolar canal and thin cortex of the mandible were found to be reliable diagnostic criteria for thalassaemia major.

Adolescent↗
PubMed2001

Biological guides to the positioning of the artificial teeth in complete dentures.

Setting teeth for complete dentures is traditionally done away from the clinic in the dental laboratory. This has unwittingly given the impression that arranging tooth position is a mechanical process in which the clinician has little say. Many technicians are given few instructions, but a detailed prescription is crucial to the success of the denture. This article describes those considerations the dentist should address in communicating with the laboratory technician. A 'denture space' impression technique is described to assist the dentist in the correct prescription for posterior teeth placement.

Cephalometry↗
PubMed2002

The timing of orthodontic treatment.

The time at which orthodontic treatment should be started remains a matter of conjecture. Anomalies of dental development and functional problems tend to be addressed in the mixed dentition, while definitive treatment tends to be delayed until the late mixed dentition to maximize growth potential and patient compliance. However, some clinicians advocate starting treatment earlier in certain types of malocclusion. In this article, the current concepts of early treatment, both physiological and psychological, will be explored and the relevant indications and contraindications discussed.

Adolescent↗
PubMed1978

The geometric theory of selection of artificial teeth: is it valid?

The study was done to determine the validity of William's geometric theory of tooth selection. The maxillary central incisors of 31 subjects were radiographed and photographed; casts were made of the maxillas; and the subjects' faces were photographed. Three dentists classified the form of the maxillary central incisors as shown by intraoral photographs, radiographs made by the parallelling technique, and casts, and also classified the form of the face from frontal-view photographs. The data collected were reduced by an electronic computer to determine if a correlation exists. There was no correlation between the form of the face and the form of the maxillary central incisors.

Cephalometry↗