Correlations among chronological age, cervical vertebral maturation index, and Demirjian developmental stage of the maxillary and mandibular canines and second molars.

PURPOSE: Estimation of growth spurt from chronological age or dental development is of clinical interest to orthodontists. Since results in this regard are highly controversial and limited, this study was conducted to investigate associations among chronological age, skeletal development (cervical vertebral maturity [CVM]), and dental calcification (Demirjian) in girls and boys, independently. METHODS: Panoramic radiographs and lateral cephalographs of 112 boys and 112 girls were evaluated. Demirjian stages of dental development of the bimaxillary canines and second molars were determined. CVM stages of skeletal growth were as well estimated. Correlations among these were assessed. Differences between sexes and between maxilla/mandible arches were assessed. Cutoff points in Demirjian and chronological age reflecting skeletal growth spurt were found using receiver operator characteristic curve (α = 0.05, ß = 0.9 separately for girls and boys). RESULTS AND CONCLUSIONS: Sex dimorphism existed both in CVM index and in Demirjian indexes. Compared to dental development and calcification, chronological age was the best predictor of skeletal growth and maturation. In estimating chronological age by radiography means, in girls, Demirjian method was better than CVM. In boys, Demirjian was better than CVM in the case of the molars but not canines. The cutoff points estimated for chronological age and dental calcification that can reflect skeletal growth spurt (between CS-3-and-CS-4) were as follows: in boys, age of 12 years; in girls, age between 11 and 12 years; the upper and lower canines: between G and H; the maxillary and mandibular second molars: between F and G; in the case of all teeth: between F and G.

Faster growth corresponds with shallower linear hypoplastic defects in great ape canines.

Deeper or more 'severe' linear enamel hypoplasia (LEH) defects are hypothesized to reflect more severe stress during development, but it is not yet clear how depth is influenced by intrinsic enamel growth patterns. Recent work documented inter- and intraspecific differences in LEH defect depth in extant great apes, with mountain gorillas having shallower defects than other taxa, and females having deeper defects than males. Here, we assess the correspondence of inter- and intraspecific defect depth and intrinsic aspects of enamel growth: enamel extension rates, outer enamel striae of Retzius angles, and linear enamel thickness. Thin sections of great ape canines (n = 40) from Gorilla beringei beringei, Gorilla gorilla gorilla, Pan troglodytes, and Pongo spp. were analyzed. Enamel extension rates were calculated within deciles of enamel-dentine junction length. Linear enamel thickness and the angle of intersection between striae of Retzius and the outer enamel surface were measured in the imbricational enamel. Mountain gorillas have faster enamel extension rates and shallower striae angles than the other taxa examined. Mountain gorillas have thinner imbricational enamel than western lowland gorillas and orangutans, but not chimpanzees. In the combined-taxon sample, females exhibit larger striae angles and thicker imbricational enamel than males. Enamel extension rates are highly negatively correlated with striae angles and LEH defect depth. Enamel growth variation corresponds with documented inter- and intraspecific differences in LEH defect depth in great ape canines. Mountain gorillas have shallower striae angles and faster extension rates than other taxa, which might explain their shallow LEH defect morphology and the underestimation of their LEH prevalence in previous studies. These results suggest that stressors of similar magnitude and timing might produce defects of different depths in one species or sex vs. another, which has implications for interpretations of stress histories in hominins with variable enamel growth patterns.

Does headgear treatment in young children affect the maxillary canine eruption path?

Objective: To test whether early headgear (HG) treatment and space conditions in the dental arch affect the eruption pathway of the maxillary canines in young children with mixed dentition. Subjects and methods: Data from two randomized controlled trials studying the effects of early HG treatment were pooled, yielding a study sample comprising 99 children (38 girls and 61 boys, mean age 7.6 years) with Angle Class II occlusion. Fifty-one children were treated with HG and 48 children served as an untreated control group (CG). Digital 3D models and panoramic radiographs were taken before (T0) and after (T1) treatment, and changes in the maxillary canine eruption angle and interdental spaces were measured at T0 and T1. A paired samples t-test was used to assess changes in maxillary canine angulation, and an independent samples t-test was used to evaluate the effect of HG treatment on spacing in the dental arch. Associations between intra-arch space conditions and changes in maxillary canine angulation were estimated with linear regression models. Results: The eruption pattern of the permanent canine was significantly more vertical in the HG group than in the CG. The linear regression models showed a statistically significant association among the intercanine distance, crowding in the anterior part of the maxilla, and changes in the maxillary canine eruption angle. The maxillary canine eruption pattern changed significantly more to a vertical direction in spaced dental arches than in crowded dental arches in the HG group. Conclusion: This study shows that early HG treatment in children with Angle Class II occlusion may change the eruption pattern of permanent maxillary canines to a more vertical direction. This change appears to be related to space conditions in the maxillary arch, especially in the intercanine region, with more effect in children with spaced dental arches than in children with crowded dental arches.

Improved eruption path quantification and treatment time prognosis in alignment of impacted maxillary canines using CBCT imaging.

Background/objective: Orthodontic alignment of impacted upper canines is desirable for functional and aesthetic reasons, but time-consuming and difficult. Estimated treatment time is thus an important factor in treatment planning, its predictability based on hitherto available two-dimensional radiological measurements, however, quite limited (max. 39.1-42%). We thus aimed to improve treatment time prognosis of palatally impacted upper canines based on a three-dimensional quantification of eruption path length in baseline cone-beam computed tomographical (CBCT) diagnostic data. Materials and methods: Baseline CBCT and orthopantomogram (OPT) data and treatment times of 30 adolescent non-syndromic/cleft orthodontic patients with an unilaterally palatally impacted upper canine, aligned by fixed orthodontic non-extraction traction treatment (closed eruption), were retrospectively analysed. Eruption path length was quantified by conventional two-dimensional and new three-dimensional methods, correlated with time to canine alignment and a prediction equation derived by linear regression. Results: CBCT and OPT eruption path length and time to canine alignment did not show significant gender, age, or impaction side differences, but CBCT methods a distinct correlation (r = 0.856/0.844, P < 0.001) and high concordance [Lin's concordance correlation coefficient (CCC) = 0.9438]. Linear regression yielded a predictability (r2 × 100%) of time to canine alignment from eruption path length of 73.3 per cent (CBCT trigonometry), 71.3 per cent (CBCT-simplified), and 50.0 per cent (OPT), respectively. Limitations: The proposed model for treatment time prediction is only valid for eruption path lengths up to 8 mm. In some cases of canines being defined as impacted, these may have had the potential of spontaneous eruption. Possible inter-individual differences have to be considered. Conclusions: Treatment time prediction for alignment of impacted upper canines can be achieved at an improved certainty of up to 73.3 per cent by the proposed CBCT methods for quantifying eruption path length compared to OPT measurements. Due to absence of gender, age, and impaction side differences, the derived regression formula should be universally usable in non-syndromic/cleft adolescents with palatally impacted upper canines.

Associated parameters of canine impaction in patients with unilateral cleft lip and palate after secondary alveolar bone grafting: a retrospective study.

Objectives: To compare parameters related to impacted canines at the cleft versus the normal contralateral side and with non-impacted canines at the cleft side in unilateral cleft lip and palate (UCLP) patients. We also aim to search for possible associated parameters enabling prediction of canine impaction in these patients. Materials and methods: Ninety-five non-syndromic UCLP patients were included and divided into group A (n = 41 patients) with unilateral impacted canines at the cleft side (A1) and spontaneously erupted canines at the non-cleft side (A2) and group B with spontaneously erupted canines at the cleft side (n = 54 patients). Clinical information and radiographic parameters on panoramic radiographs were collected and compared between groups using a generalized linear mixed model, a Mann-Whitney U-test, a Fisher's exact test, and receiver operating characteristic tests. Results: Impaction of the maxillary canine at the cleft side in UCLP patients can be suspected in case of delayed canine root development, a higher vertical position and sector score (P < 0.05) and higher angles between the canine and the midline, as well as between canine and lateral incisor and between first premolar (P < 0.001). Results clearly indicate that the erupting canine position at the cleft side, even when not impacted, is different from the non-cleft side. Conclusion: There is a great risk for canine impaction at the cleft side in UCLP patients when the canine position is more apical than one-third of the root of the adjacent lateral incisor and when the angles between canine and midline and between canine and first premolar are higher than 23.82 and 16.1 degrees, respectively. These associated parameters should have to be studied in a prospective setting to confirm their predictive value.

Position and Eruption of Permanent Maxillary Canines in Cases of Maxillary Lateral Incisor Agenesis in Mixed Dentition.

OBJECTIVE: Assess whether the permanent maxillary canine (MC) has a natural tendency to erupt mesially in children with maxillary lateral incisors agenesis (MLIA), compared to children without agenesis. STUDY DESIGN: This retrospective, observational, cross-sectional study consisted of children between 5 and 12 years old divided into three groups: the first group with unilateral MLIA, in which an intraindividual analysis was performed, the second group presented bilateral MLIA, and the third group with patients without agenesis. These last two groups were matched for comparison interindividual, being pared by sex and maturation of the MC. RESULTS: The canine position in the horizontal sector showed a clear mesial positioning of the MC on the agenesis side in individuals with unilateral MLIA (group 1) when compared with the counter lateral side; and in individuals with bilateral MLIA (Group 2) compared with control Individuals without agenesis (group 3). Even with the maintenance of this deciduous tooth in the dental arch, the MC keeps its tendency to mesial eruption. CONCLUSION: There is a greater tendency for mesial angulation of the maxillary canine in patients with MLIA, regardless of the presence or absence of deciduous lateral incisor.

Speed of human tooth movement in growers and non-growers: Selection of applied stress matters.

OBJECTIVES: To test that the speed of tooth translation is not affected by stress magnitude and growth status. SETTING AND SAMPLE POPULATION: Advanced Education Orthodontic clinics at the Universities of Nebraska Medical Center and Missouri-Kansas City. Forty-six consenting subjects with orthodontic treatment plans involving maxillary first premolar extractions. MATERIALS AND METHODS: This randomized split-mouth study used segmental mechanics with definitive posterior anchorage and individual vertical-loop maxillary canine retraction appliances and measured three-dimensional tooth movements. Height and cephalometric superimposition changes determined growing (G) and non-growing (NG) subjects. Subjects were appointed for 9-11 visits over 84 days for maxillary dental impressions to measure three-dimensional tooth movement and to ensure retraction forces were continuously applied via calibrated nitinol coil springs. Springs were custom selected to apply two different stresses of 4, 13, 26, 52 or 78 kPa to maxillary canines in each subject. Statistical analyses (α=0.050) included ANOVA, effect size (partial η2 ) and Tukey's Honest Significant Difference (HSD) and two-group t tests. RESULTS: Distolateral translation speeds were 0.034±0.015, 0.047±0.019, 0.066±0.025, 0.068±0.016 and 0.079±0.030 mm/d for 4, 13, 26, 52 and 78 kPa, respectively. Stress significantly affected speed and partial η2 =0.376. Overall, more distopalatal rotation was shown by teeth moved by 78 kPa (18.03±9.50º) compared to other stresses (3.86±6.83º), and speeds were significantly higher (P=.001) in G (0.062±0.026 mm/d) than NG subjects (0.041±0.019 mm/d). CONCLUSIONS: Stress magnitude and growth status significantly affected the speed of tooth translation. Optimal applied stresses were 26-52 kPa, and overall speeds were 1.5-fold faster in G compared to NG subjects.

Utility of panoramic radiography for identification of the pubertal growth period.

INTRODUCTION: Our aim in this study was to investigate the association between dental mineralization stages and the periods of the pubertal growth spurt (PGS). METHODS: The sample included panoramic and hand-wrist radiographs from 491 subjects (222 boys, 269 girls) aged 7 to 17 years. Dental development was rated, and skeletal maturation was evaluated. The relevant associations were investigated by analysis of ordinal multinomial logistic regression. RESULTS: The second molar (odds ratio [OR] = 4.34) and the first premolar (OR = 2.45) were the best growth predictors for girls. For boys, the second molar (OR = 6.80), second premolar (OR = 2.41), and canine (OR = 3.21) proved to be the best predictors. Stages D and E of the second molar for girls, and stages E and F for boys, corresponded to the onset of the accelerated growth spurt. Stage F of the second molar for girls and stage G for boys corresponded to the peak of the PGS. At the end of the PGS, most teeth had already attained apical closure. In girls, however, most second molars were found at stage G. CONCLUSIONS: An association exists between the dental mineralization stages and the periods of the PGS, especially for second molars. Panoramic radiographs can be used as the first diagnostic tool to estimate the pubertal growth period.

Evaluation of skeletal maturity using maxillary canine, mandibular second and third molar calcification stages.

OBJECTIVE: The objective of this study was to evaluate whether the calcification stages of maxillary canine, mandibular second molar, and mandibular third molar can be used for assessment of growth phase. MATERIALS AND METHODS: The study group consisted of 274 subjects. Pre-treatment digital panoramic and lateral cephalometric radiographs of the patients were analysed. The patients' age was ranging from 7 to 19 years. Right maxillary canine, mandibular second molar and third molar were used as a sample. The teeth mineralization was assessed using modification of Gleiser and Hunt method. The skeletal maturation was assessed by the cervical vertebrae maturation (CVM) method. RESULTS: A significant association was found between CVM stage 2 and maxillary canine (UC) stage 4, mandibular second molar (LM2) stage 4, and mandibular third molar (LM3) stage 1. CVM stage 3 corresponded with UC stage 5, LM2 stage 5, LM3 stage 2. CVM stage 4 matched with UC stage 5, LM2 stage 6 and LM3 stage 3. The highest correlations between CVM and calcification stages were in the group of the maxillary canine (r = 0.812, P < 0.01) and mandibular second molar (r = 0.824, P < 0.01). LIMITATIONS: Limitation of our study was that the study sample was not very big and the distribution value in the groups was very high, so it was impossible to check more statistical parameters. CONCLUSIONS: The calcification stages of UC, LM2, and LM3 as indicators of skeletal maturity could be clinically used with caution, until this method is verified with a larger sample group.

Combining radiographic and histological data for dental development to compare growth in the past and the present.

BACKGROUND: Being able to estimate the age at death of fossil hominins enables meaningful comparisons of both dental and general growth, past and present. AIM: The aim of this study was to use data for modern permanent canine formation derived from separate histological and radiographic studies to estimate the age at death of an early African Homo erectus specimen (KNM-WT 15 000) with a developing permanent maxillary canine. METHODS: Ground sections of 18 sexed modern human canines were used to reconstruct growth in tooth height along the enamel-dentine junction (EDJ) and onwards into root formation along the cement-dentine junction (CDJ). Daily rates of enamel and dentine formation were used to put a time scale to cumulative fractions of tooth height. RESULTS: Age estimates for KNM-WT 15 000 averaged 7.89-8.8 years of age (range = 6.6-10.3 years) and were close to previous histological estimates for this individual (7.6-8.8 years). CONCLUSIONS: Stages of dental development in KNM-WT 15 000 were easily accommodated within this age distribution of a modern sample. However, body mass and stature estimates for KNM-WT 15 000 fell well beyond those reported for a modern sample of 438 Sudanese children aged between 7.0-10 years.

Effects of mechanical stress and growth on the velocity of tooth movement.

INTRODUCTION: In this study, we investigated the effects of the magnitudes of applied stress and growth status on the speed of tooth movement. METHODS: Eighty-two maxillary canines in 41 subjects were retracted for 84 days by estimated stresses of 4, 13, 26, 52, or 78 kPa applied continuously via segmental mechanics. Dental impressions made at intervals of 1 to 14 days resulted in 9 or 10 dental casts per subject. Three-dimensional tooth movements were quantified using these casts, custom reference templates, and a measuring microscope. Serial height and cephalometric measurements determined growth status. RESULTS: Distal tooth movement was linear with no lag phase in 96% of the teeth. Speeds averaged 0.028, 0.040, 0.050, 0.054, and 0.061 mm per day (standard errors, ± 0.004) for 4, 13, 26, 52, and 78 kPa, respectively. The maximum difference in speed between teeth was 9:1. Teeth moved significantly faster (P <0.0001) in growing compared with nongrowing subjects, on average by 1.6-fold. Stress and speed of tooth movement were logarithmically related in growing (R(2) = 0.47) and nongrowing (R(2) = 0.34) subjects. Other tooth movements were relatively small, except for the distopalatal rotation of teeth moved by 78 kPa that averaged more than 19°. CONCLUSIONS: The speed of retraction was logarithmically related to the applied stress and was significantly faster in actively growing subjects compared with those who were not growing.

Tooth mineralization stages as a diagnostic tool for assessment of skeletal maturity.

INTRODUCTION: The objective of this study was to determine whether dental calcification can be used as a first-level diagnostic tool for assessment of skeletal maturity. METHODS: A total of 150 healthy subjects (79 boys, 71 girls; mean age, 12.19 ± 2.03 years; range, 8-16 years) were enrolled in the study. Dental maturity was assessed through the calcification stages from panoramic radiographs of the mandibular canine, the first and second premolars, and the second molar. Determination of skeletal maturity was according to the modified middle phalanx of third finger (MP3) stages method on digital radiographs. RESULTS: Diagnostic ability was evaluated according to the dental maturation stages for each tooth for identification of the MP3 stages and the growth phases (prepubertal, pubertal, postpubertal) using positive likelihood ratios. Dental maturation stage E of the first premolars and the combination of canine stage F, first premolar stage E, second premolar stage E, and second molar stage D (FEED) gave the highest values for identification of the prepubertal growth phase, and stage H of the second molar had the highest value for identification of the postpubertal growth phase. CONCLUSIONS: Dental maturation assessment is only useful for diagnosis of the prepubertal and postpubertal growth phases.

Incremental enamel development in modern human deciduous anterior teeth.

This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204-214) to identify developmental differences along the tooth row. Two hypotheses are tested: Retzius line periodicity will remain constant in teeth from the same jaw and range from 6 to 12 days among individuals, as in human permanent teeth; daily enamel secretion rates (DSRs) will not vary between deciduous teeth, as in some human permanent tooth types. A further aim is to search for links between deciduous incremental enamel development and the previously reported eruptionsequence. Retzius line periodicity in anterior teeth ranged between 5 and 6 days, but did not differ between an incisor and molar of one individual. Intradian line periodicity was 12 h. Mean cuspal DSRs varied slightly between equivalent regions along the tooth row. Mandibular incisors initiated enamel formation first, had the fastest mean DSRs, the greatest prenatal formation time, and based upon prior studies are the first deciduous tooth to erupt. Relatively rapid development in mandibular incisors in advance of early eruption may explain some of the variation in DSRs along the tooth row that cannot be explained by birth. Links between DSRs, enamel initiation times, and the deciduous eruption sequence are proposed. Anterior crown formation times presented here can contribute toward human infant age-at-death estimates. Regression equations for reconstructing formation time in worn incisors are given.

Unicuspid and bicuspid tooth crown formation in squamates.

The molecular and developmental factors that regulate tooth morphogenesis in nonmammalian species, such as snakes and lizards, have received relatively little attention compared to mammals. Here we describe the development of unicuspid and bicuspid teeth in squamate species. The simple, cone-shaped tooth crown of the bearded dragon and ball python is established at cap stage and fixed in shape by the differentiation of cells and the secretion of dental matrices. Enamel production, as demonstrated by amelogenin expression, occurs relatively earlier in squamate teeth than in mouse molars. We suggest that the early differentiation in squamate unicuspid teeth at cap stage correlates with a more rudimentary tooth crown shape. The leopard gecko can form a bicuspid tooth crown despite the early onset of differentiation. Cusp formation in the gecko does not occur by the folding of the inner enamel epithelium, as in the mouse molar, but by the differential secretion of enamel. Ameloblasts forming the enamel epithelial bulge, a central swelling of cells in the inner enamel epithelium, secrete amelogenin at cap stage, but cease to do so by bell stage. Meanwhile, other ameloblasts in the inner enamel epithelium continue to secrete enamel, forming cusp tips on either side of the bulge. Bulge cells specifically express the gene Bmp2, which we suggest serves as a pro-differentiation signal for cells of the gecko enamel organ. In this regard, the enamel epithelial bulge of the gecko may be more functionally analogous to the secondary enamel knot of mammals than the primary enamel knot.

Relationship between dental age according to Demirjian and cervical vertebrae maturity in Polish children.

The purpose of the study was to investigate the relationship between Demirjian's method and the improved cervical vertebrae maturation (CVM) method. The material consisted of the clinical files and panoramic and lateral cephalometric radiographs of 718 children (431 girls and 287 boys) aged from 6 to 17 years, inhabitants of the Mazovia region (Central Poland). Dental age according to Demirjian was estimated using panoramic radiographs and the cervical stages (CS) of the CVM were evaluated on cephalometric radiographs. Descriptive statistics of the chronological and dental ages of the patients for a particular CS of skeletal maturity was calculated for girls and boys separately. Linear regression analysis and correlation (Pearson's r coefficient), as well as the Spearman rank correlation coefficient (R) were applied to measure the association between CS and dental calcification stages of all analysed teeth. A consistently earlier occurrence (by about 6 months) for each CS was observed in females. A moderate, but statistically significant, correlation between Demirjian's dental developmental stages and CS was determined. The level of the correlation was different for individual teeth: the teeth showing the highest relationship with CVM were the second premolars and canines (in female and male subjects, respectively). The central incisor demonstrated the poorest correlation in both genders. The findings confirmed that both dental and skeletal maturity should be assessed if the maturity stage of a growing child is to be relevant to clinical practice. The results indicate the usefulness of dental calcification stages as a simple first-level diagnostic test to determine the skeletal maturity status of a subject.

Correlation between cervical vertebral and dental maturity in Iranian subjects.

Determination of the skeletal maturation is extremely important in clinical orthodontics. Cervical vertebral maturation is an effective diagnostic tool for determining the adolescent growth spurt. The aim of this study was to investigate the correlation between the stages of calcification of teeth and the cervical vertebral maturity stages.

Longitudinal observation of developmental change in maxillary deciduous and permanent canines.

During the period of the growth and development of the dental arch, anterior-posterior and medial-lateral changes in the maxillary deciduous and permanent canines were longitudinally studied in children. A longitudinal series of dental casts were obtained from 50 children at 2-month intervals from the completion of deciduous dentition to the stable period of permanent dentition. Subjects were divided into two groups according to the arrangement of the permanent teeth: a normal dental arch group and a crowded dental arch group. The mesial and distal points of the deciduous and permanent canines and the most prominent points on the labial and lingual contours were observed longitudinally. The results indicated that the measurement points of the deciduous canines in the normal and crowded groups moved in the anterior and lateral direction. When the amount of movement in the normal group was compared to that in the crowded group, the normal group showed greater movement than the crowded group. The permanent canines in both groups moved in the anterior and medial directions. When the amount of movement in the normal group was compared to that in the crowded group, the normal group showed more anterior movement than the crowded group, and the crowded group showed more medial movement than the normal group. When the distal point of the permanent canine was compared with the point of the deciduous canine at the exfoliation period in the normal arch group, the permanent canine was in almost the same position or was in a more anterior position than the deciduous canine. In the crowded arch group, the permanent canine tended to drift posteriorly.

Surprisingly rapid growth in Neanderthals.

Life-history traits correlate closely with dental growth, so differences in dental growth within Homo can enable us to determine how somatic development has evolved and to identify developmental shifts that warrant species-level distinctions. Dental growth can be determined from the speed of enamel formation (or extension rate). We analysed the enamel extension rate in Homo antecessor (8 teeth analysed), Homo heidelbergensis (106), Homo neanderthalensis ('Neanderthals'; 146) and Upper Palaeolithic-Mesolithic Homo sapiens (100). Here we report that Upper Palaeolithic-Mesolithic H. sapiens shared an identical dental development pattern with modern humans, but that H. antecessor and H. heidelbergensis had shorter periods of dental growth. Surprisingly, Neanderthals were characterized by having the shortest period of dental growth. Because dental growth is an excellent indicator of somatic development, our results suggest that Neanderthals developed faster even than their immediate ancestor, H. heidelbergensis. Dental growth became longer and brain size increased from the Plio-Pleistocene in hominid evolution. Neanderthals, despite having a large brain, were characterized by a short period of development. This autapomorphy in growth is an evolutionary reversal, and points strongly to a specific distinction between H. sapiens and H. neanderthalensis.

Delayed dental maturity in dentitions with agenesis of mandibular second premolars.

OBJECTIVES: To evaluate dental maturity in the mandibular canine/premolar and molar innervation fields in children with agenesis of the 2nd mandibular premolar and to associate these findings with normal control material. SETTING AND SAMPLE POPULATION: Department of Orthodontics, Institute of Odontology, University of Copenhagen. Eighty-three panoramic radiographs (27 girls and 31 boys with agenesis of one mandibular 2nd premolar and 17 girls and eight boys with agenesis of both mandibular 2nd premolars) represented all mandibular second premolar agenesis cases from a material of 2847 radiographs. MATERIAL AND METHODS: On each radiograph, dental maturity of all available mandibular premolars, canines and 2nd molars was evaluated and categorized in maturity stages according to Haavikko whose material served as control material. Descriptive statistics given by sample mean, standard deviation and range for each tooth stratified by gender and agenesis. Ninety-five percentage confidence limits and T-statistics were used. p-values <5% were considered significant. RESULTS: In unilateral agenesis, the canines are specifically delayed in both girls and boys, with a larger delay in girls (p=0.009). The second molar is not delayed in boys (p=0.98) but is in girls (p=0.04). The differences in delay for the canine compared to the second molar are significant for both girls and boys. The results show a considerable delay in tooth maturation within the canine/premolar innervation field predominantly in girls. The 2nd molar is delayed in girls but not in boys.

Autologous bone grafting with adjunctive use of acellular dermal matrix for alveolar cleft defects: early outcomes.

BACKGROUND AND PURPOSE: Alveolar bone grafting remains the standard for alveolar cleft repair. Compromised oral and/or nasal closure may impede healing and result in graft failure or persistent fistulae. Incorporating acellular dermal matrix into these repairs may protect the bone graft during mucosal healing by providing an additional layer of soft tissue coverage. METHODS: A retrospective review of alveolar bone grafts undertaken at our cleft-craniofacial center from 2005 to 2007 was performed. The use of acellular dermal matrix for nasal and/or oral lining augmentation was determined. A minimum 3 months' follow-up was required for inclusion. Outcomes included (1) mucosal disruption, (2) time to complete mucosal healing, (3) bone graft exposure, (4) postoperative bone graft incorporation using the Chelsea scale, and (5) canine eruption through the graft site. RESULTS: In total, 35 patients were included. Of those, 15 patients (four girls, 11 boys; seven Veau III, eight Veau IV) received acellular dermal matrix for mucosal augmentation (five nasal, one oral, nine nasal and oral lining). Average age at surgery was 10 years (range, 9 to 16 years). Average follow-up was 23 months (range, 3 to 35 months). Mucosal disruption occurred in 20% of the acellular group and in 30% of the control group (p=nonsignificant). Complete mucosal healing was achieved at an average of 4 weeks (range, 1 to 14 weeks) in the acellular dermal matrix group versus 4 weeks (range, 2 to 11 weeks) in the control group (p=nonsignificant). Exposure of bone graft occurred in 0% of the acellular dermal matrix group and in 30% of the control group (p=.016). The Chelsea scale demonstrated no significant radiographic difference in postoperative bone graft incorporation between the acellular dermal matrix and control groups. Canine eruption through the graft site was similar for both groups. CONCLUSIONS: These data support the conclusions that using acellular dermal matrix to augment nasal/oral mucosal lining in alveolar bone grafts (1) does not increase mucosal disruption or time to complete healing, (2) prevents postoperative bone graft exposure, and (3) appears to have no negative effect on postoperative bone graft incorporation or canine eruption through the graft site.