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Shifts in tooth maturation patterns in non-French Canadian boys.

AIMS: This study was designed to evaluate the predictability of dental maturation patterns in non-French Canadian boys using the maturation curves developed by Demirjian & Goldstein [1]. SAMPLE: Archival cephalometric radiographs taken during a longitudinal study (1930-1960) of Caucasian Americans were re-evaluated. METHODS: Maturation of the permanent teeth on the left side of the mandible was determined according to the methods described by Demirjian & Goldstein. RESULTS: Of the 79 boys studied, 12 (15.2%) started below Demirjian's median and continued as such during the maturation process. Seven (8.9%) started within the second standard deviation above Demirjian's median and continued as such during the maturation process. The remaining 60 boys (75.9%) started below the median of Demirjian's curves at an early age. They matured at a rate that placed them above the median value at the end of the study period. The shift took place before the age of 6 years in 46 (76.6%) cases and between the ages of 6 and 8 years in another nine (15%) cases. In five of the cases which started below Demirjian's median (8.3%) the shift only took place after the age of 9 years. CONCLUSION: The shift from below median to above median value was considered an important factor in treatment planning. The data indicate that there is considerable risk for treatment planning prior to the age of 8 years. The risk is highest when the children are less than 6 years of age due to growth prediction uncertainties.

Canada↗

Dental maturation of 18th and 19th century British children using Demirjian's method.

AIM: To compare dental age with chronological age in a group of children born approximately 200 years ago and a group of modern children. METHODS: Dental maturation of 15 skeletal remains (range 3.0-15.1 years) of London children of known age-at-death was compared to an age and sex matched control group of contemporary children (n = 30). The method of Demirjian, Goldstein and Tanner (1973, 1976, 1978) was used to assess maturity. RESULTS: The difference between dental age (DA) and chronological age (CA) for both groups was not significant, suggesting similar maturation over 200 years, however, many of the younger children from Spitalfields were dentally delayed. Several of the younger individuals from both groups had a dental age less than the lowest limit of this scale (2.5 years), highlighting one pitfall of this method. CONCLUSION: These results suggest that this method is not entirely suitable for younger children.

Adolescent↗

Bilateral macrodontia of mandibular second premolars: a case report.

Macrodontia of single teeth is rare. This has been reported on only six occasions in scientific journals when affecting mandibular second premolars with associated morphological anomalies. The large crown size causes problems with eruption, and disrupts the dentition. There are consequent inherent difficulties for the extraction of these teeth. Once erupted, their anatomy predisposes them to caries. Most cases are seen in children, before interventive surgery has been completed. The morphological anomalies of these premolar Macrodonts appear quite distinct and may justify a separate unique categorization.

Bicuspid↗

The dentofacial manifestations of XXXXY syndrome: a case report.

This paper presents a six-year-old patient with XXXXY syndrome, whose oral findings included a cleft soft palate, hyper- or meso-taurodontism in eight primary molars and in the mandibular permanent first molars, five congenitally missing premolars, and delayed development of the permanent tooth germs. The maxillary and mandibular primary central incisors were in a cross-bite relationship. Cephalometric findings showed a short ramus of the mandible and a short maxilla in the anterioposterior plane. The anteroposterior jaw relationship was in harmony. The cross-bite was considered to be due to the retroinclination of the maxillary primary incisors. This case emphasises the importance of regular dental care, and monitoring of facial growth and dental development in children with XXXXY syndrome.

Anodontia↗

Assessment of dental maturity of Brazilian children aged 6 to 14 years using Demirjian's method.

UNLABELLED: Dental maturity, often expressed as dental age, is an indicator of the biological maturity of growing children. A method for the assessment of dental maturity was first described by Demirjian, and is widely used and accepted, mainly because of its ability to compare different ethnic groups. This is possible, as the maturity scoring system proposed by the method is universal in application, although the conversion to dental age depends on the population considered. OBJECTIVES: The aim of this study was to apply Demirjian's method to Brazilian children aged 6-14 years in order to obtain dental maturity curves for each sex, to compare this data with that obtained by Demirjian, and to determine whether there is a significant correlation between dental maturity and body mass index. METHODS: We retrospectively reviewed the orthopantomograms, height and weight measurements of 689 healthy children. Curves of dental maturity of males and females were constructed. RESULTS: When compared to the French-Canadian sample of Demirjian, Brazilian males and females were 0.681 years and 0.616 years, respectively, more advanced in dental maturity. There was no significant correlation between dental maturity and body mass index.

Adolescent↗

Occlusion and tooth/arch dimensions in the primary dentition of preschool Jordanian children.

OBJECTIVES: To assess tooth and arch dimensions, occlusal relationships and the presence of spacing or crowding in primary dentition of Jordanian children. STUDY DESIGN: A list of 10 kindergartens was randomly selected in the governate of Irbid, Jordan. A total of 1048 children (2.5-6 years old) with complete primary dentitions were examined for occlusal relationships in three planes, and the presence of spacing or crowding. Of those, study casts were taken for 87 randomly selected 4-5-year-old children (39 girls, 48 boys). Measurements of tooth and arch dimensions were made using electronic digital sliding callipers. RESULTS: In general, males had larger mesiodistal tooth width and larger arch dimensions. Bilateral mesial step molar relationship was found in 47.7% of children followed by bilateral flush terminal molar relationship in 37% and bilateral distal step in 3.7%. Asymmetric right/left molar relationship was found in 11.6% of children examined. Class I canine relationship was found in 57% of children, followed by Class II canines in 29% and Class III canines in 3.7%. Fifty per cent of children examined had Class I incisors, 24.7% had Class II Division 1, 13.5% had Class II Division 2 and 11.8% showed reversed overjet. Ideal overbite was seen in 44.3% of children, reduced overbite in 21.8%, increased overbite in 28.2% and 5.7% had anterior openbite. Buccal crossbite was seen in 7% of the sample. Generalized spacing was found in 61.8% and 61.1% of children in the upper and lower arches, respectively. Anthropoid spaces were found in 70% of the upper arches and in 51% of the lower arches. CONCLUSIONS: Males had larger tooth/arch dimension than that of females in the primary dentition stage. Mesial step molar relationship was found in 47.7% of the subjects followed by flush terminal molar relationship in 37%. The majority of children examined had spaced primary dentition.

Cephalometry↗

Increased primary tooth size in a 47,XXY male: a first case report.

Increased tooth size has previously been reported in association with Klinefelter syndrome. However, until now, this observation has been restricted to the permanent dentition. In this paper, we report increased mesio-distal width in the primary incisor and molar teeth of a 47,XXY male.

Child↗

A cross-sectional study of canine dimorphism in establishing sex identity: comparison of two statistical methods.

The occurrence of canine tooth dimorphism in Indian subjects has been investigated and the use of two statistical methods of evaluation compared. These were the methods of N.G. Rao and co-workers published in 1988 and quadratic discriminant analysis for correct classification of sex. Parameters considered were (i) the mesiodistal width of maxillary and mandibular canines, (ii) the maxillary canine arch width (intercanine distance) and (iii) the mandibular canine arch width. The results indicated significant dimorphism of the maxillary and mandibular canine teeth. When the results of the arch widths were subjected to the two statistical methods, differing results were obtained in the accuracy of sex classification. The percentage of correct classifications of sex was higher when using quadratic discriminant analysis.

Adolescent↗

An optical system for measuring inclination and area of occlusal facets.

Occlusal facets are regarded as an individual record of occlusal contacts that result from various mandibular movements. Analysing characteristics of the facets is important for the functional assessment of the stomatognathic system. A new system which quantifies such characteristics optically has been developed. This system is composed of optical devices, a graphic image-processor, a set of stages for mounting and positioning the model and laser indicators of the measuring point. The system enables the inclination and area of each facet and its location to be measured and its processed image displayed on the graphic monitor.

Computer Graphics↗

Incline and length of guiding elements in untreated naturally grown dentition.

The incline and length of guiding elements, i.e. marginal ridges and lingual surfaces of front teeth, marginal ridges and internal cusp slopes of premolars and molars, play an important role in dentistry. Since the so far reported values differ considerably, it was the purpose of the present investigation to replicate the measurements, including all the occlusal landmarks proposed and defined by previous investigators. The measurements were performed on 34 pairs of mounted casts from a selected group of untreated, naturally grown dentitions from adolescents of mean age 14 years. The upper casts were mounted with a face bow, the kinematic hinge axis and the left incisura infraorbitalis representing the posterior and anterior reference points. The lower pinned casts were mounted joint related. All measurements were carried out with a computer-aided, three-dimensional digitizer. The inclines were expressed as angles related to the axis-orbital-plane. Taking the proposed occlusal landmarks as a basis, the inclines of guiding elements were found to be in agreement with previously reported values, despite ethnic and racial differences of the various study-populations. The values, however, differed markedly when measurements based on individual, functional relevant landmarks were compared to measurements based on anatomical, easy identifiable or mathematically constructed landmarks. The successive decrease of the inclines of the guiding elements from the central incisors to the second molars could be confirmed, the molars displaying very flat inclines. Interestingly, 9% of the first molars and 21% of the second molars showed negative values, pointing to a functional arrangement characterized by a buccally oriented occlusal surface of those teeth. Combined with the finding that the length of the guiding elements of the anterior teeth was almost twice as long as that of the posterior teeth, the results corroborate the occlusal concept of an anterior-posterior sequence of the guiding elements, or a so-called sequential guidance with front-canine-dominance.

Adolescent↗

The cusp of evolution and development: a model of cichlid tooth shape diversity.

Tooth shape is a hallmark of repeated evolutionary radiations among cichlid fishes from East Africa. Cusp shape and number vary both within populations and among closely related species with different feeding behaviors and ecologies. Here, we use histology and scanning electron microscopy to chart the developmental trajectory of tooth shape differences in fishes from Lake Malawi. We demonstrate that species with bi- or tricuspid adult (replacement) teeth initially possess a first-generation unicuspid dentition. Notably, the timing of turnover from first-generation to replacement teeth differs among species and is correlated with feeding ecology. Next, we use field data for cichlid species with adult unicuspid, bicuspid, and tricuspid teeth to demonstrate a strong and positive relationship between the number of teeth in a row and tooth shape. We discuss cichlid tooth ontogeny in the context of morphogenetic models designed to explain the developmental basis of tooth shape variation in mammals. We suggest that the dramatic differences in cichlid dentitions can be explained by variation in the expression of common activators and inhibitors acting at multiple stages of odontogenesis.

Animals↗

[The jaws of Altamira man (upper paleolithic)].

125 years ago, 25 km away from where S.F.O.D.F.'s 76th meeting was taking place, a cave displaying the wonderful art of our distant ancestors was discovered. It completely altered their image that the scientific world had had of them until then. Our ancestors artistic talents as illustrators, painters and sculptors motivated researchers to better understand their 14,000-years old culture. It also caused them to study their morphologic features and their cranio-facial typology. It is amazing to notice that we actually have more similarities with our ancestors than differences.

Adaptation, Biological↗

[Distraction osteogenesis in orthodontic surgery of the mandible].

Distraction osteogenesis is a bone creating procedure that can contribute materially to the treatment of Class II dento-skeletal disorders where the mandible is under-sized. Still, the serious commitments this treatment demands and the unpredictability of its occlusal results oblige practitioners to pinpoint precisely the indications for its use. We now believe that distraction osteogenesis can beneficially be employed for: 1--Adults with Class II malocclusions, a small mandible, and a lack of harmony between tooth and jaw size. This bone growing technique makes it possible to treat these patients without the extraction of premolars that would have been necessary in the traditional preparation for orthognathic surgery. 2--Patients whose mandibles are diminished in size in the area of the symphasis. Distraction osteogenesis of this anterior segment is the only way they can be treated without reduction of tooth structure or excessive labial tipping of teeth. 3--Some patients with short, or moderately short rami. We do not, at this time, believe that distraction osteogenesis is indicated for the treatment of any other kind of dento-facial deformity. But, in the future, improvement of surgical techniques and the miniaturization of appliances will doubtless extend its scope.

Adolescent↗

[Orthopedic expansion of the maxilla].

This paper evaluates maxillary expansion by synthesizing the scientific literature, focusing its role in treatment of maxillary insufficiency, buccal cross bites, and deviations in mandibular closure as well as its effectiveness in correcting a lack of harmony between tooth and jaw size. By its creation of maxillary bone "capital" it facilitates treatment of arch length discrepancies in an environment of periodontal health. And by restoring the maxilla to normal size it improves the orthopedic effectiveness of Class II treatment of mandibular advancement appliances. In a similar fashion rapid palatal expansion, by relaxing circum-maxillary sutures, prepares the way for maxillary advancement in Class III cases with masks of Delaire or Petit. And, by broadening the floor of the nose, palate splitting improves nasal airflow and helps mouth breathers learn how to breathe through their noses. Most authors emphasize the benefits of early intervention through truly orthopedic movement that eliminates tipping of posterior teeth and reduces the risk of buccal fenestration.

Age Factors↗

Treatment of a Class I malocclusion with a carious mandibular incisor and no Bolton discrepancy.

Occasionally orthodontists must plan treatment for a patient with extensive caries or a traumatic injury to one mandibular incisor. If the patient has a Bolton discrepancy, one treatment option could involve extraction of the affected mandibular incisor. However, if the patient does not have a Bolton discrepancy and a mandibular incisor is extracted, the treatment becomes more complicated. This case report will present and discuss the ramifications of extracting one mandibular incisor in a patient without an anterior tooth-size discrepancy. The CDABO Student Case Selection Committee chose this case for publication.

Adult↗

The Royal London Space Planning: an integration of space analysis and treatment planning: Part I: Assessing the space required to meet treatment objectives.

The Royal London Space Planning process has evolved since 1985 to ensure a disciplined approach to diagnosis and treatment planning and to provide a record to justify treatment decisions for professional accountability. The analysis takes into consideration most aspects of a given malocclusion and aims to quantify the space required in each dental arch to attain the treatment objectives. Space planning also helps determine whether the objectives are likely to be attainable and helps in the planning of treatment mechanics and the control of anchorage. The process of analysis is divided into 2 sections. The first part consists of assessing the original malocclusion according to various component parts, any of which may have an effect on space if altered during treatment. These components are crowding and spacing, occlusal curves, arch width, anteroposterior position of labial segments, mesiodistal angulation, and incisor inclination. The second part of the analysis, which will be published in a separate article, deals with the effect of treatment procedures, such as extractions, tooth-size modifications, distal or mesial molar movements, as well as natural growth, on the space required. Space planning should be regarded only as a useful guide, as many areas of orthodontics-including growth, biological response, and patient compliance-cannot be controlled with total accuracy.

Cephalometry↗

The Royal London Space Planning: an integration of space analysis and treatment planning: Part II: The effect of other treatment procedures on space.

The Royal London Space Planning process is carried out in 2 stages. The first stage, assessing the space required to attain the treatment objectives, was described in Part I of this report, published earlier. In Part II, the process of integrating space analysis with treatment planning continues with consideration of the effects other treatment procedures have on space. These procedures include tooth enlargement or reduction, tooth extraction, the creation of space for prosthetic replacement, and mesial and distal molar movement. The effects of favorable and unfavorable growth are also considered. A brief case report is presented to demonstrate use of the Royal London Space Planning.

Cephalometry↗

Triangular-shaped incisor crowns and crowding.

The purpose of this study was to establish if there is a correlation between the shape of the labial crowns of the incisors and crowding. Plaster cast models of 69 untreated individuals (30 males and 39 females) were evaluated. The casts were selected randomly from the collection at Seoul National University and Ajou University. With the use of Little's irregularity index, the sample was divided into 2 groups, a crowded group and a normal group. Repeated measurements of the maximum mesiodistal width of the incisal and cervical areas of the incisors were taken by means of a digital vernier caliper and a ratio of these measurements was calculated. The mean value for the crowded group was significantly larger in the incisal area (P <.01) and smaller in the cervical areas (P <.01) than corresponding values in the normal group. These ratios were correlated with the irregularity index (Pearson r(2) from 55% to 65%). The value obtained from the incisor width ratio in the normal group can be useful for the diagnosis and treatment of crowded malocclusion.

Case-Control Studies↗