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Biomedical subjects

L Peck

Publications and source records attributed to L Peck.

At least 19 recordsLinked to original sources
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

Mandibular lateral incisor-canine transposition, concomitant dental anomalies, and genetic control.

Mandibular lateral incisor-canine (Mn.I2.C) transposition is a rare developmental disturbance of tooth order characterized by positional interchange of the two teeth. In children with Mn.I2.C anomaly, the mandibular lateral incisor shows distal ectopic eruption and the adjacent canine subsequently erupts mesial to it. A sample of 60 orthodontic patients with Mn.I2.C transposition was studied using roentgenograms taken at the time of diagnosis. Two age-related phenotypes of the anomaly were identified: early-stage (median age, 9 years) and mature-stage (median age, 12 years). Mn.I2.C transposition occurred bilaterally in 10 subjects (17%) and favored female expression (sex ratio, M1:F3) and right-side occurrence (68% of unilateral cases). Statistically significant associations were found between Mn.I2.C transposition and increased frequency of tooth agenesis (M3, p < 0.01; MnP2, p < 0.01) and peg-shaped maxillary lateral incisors (p < 0.0001). The results from this study and the analysis of 50 previously published cases provide evidence that Mn.I2.C transposition is a disturbance of tooth order and eruptive position probably caused by genetic influences. The Mn.I2.C anomaly likely results from genetic mechanisms similar to those responsible for occurrences of its associated dental anomalies, such as tooth agenesis and peg-shaped maxillary lateral incisors. In an appendix, clinical orthodontic management of Mn.I2.C transposition is discussed, based on treatment data derived from the study sample.

Adolescent↗
PubMed1996

Prevalence of tooth agenesis and peg-shaped maxillary lateral incisor associated with palatally displaced canine (PDC) anomaly.

Fifty-eight nonsyndromic North American white orthodontic patients with palatal displacement of one or both maxillary canine teeth were studied for associated tooth agenesis and peg-shaped maxillary lateral incisors. Agenesis of permanent teeth was identified by x-ray film analysis. Conical crown-size reduction (peg-shape anomaly) of the maxillary lateral incisor (l2) was determined by direct observation. Increases in absence of third molars and second premolars associated with the palatally displaced canine (PDC) anomaly were statistically very highly significant compared with normative data for tooth-agenesis prevalence. In contrast, the prevalence of l2 agenesis in the PDC sample showed no difference statistically compared with reference values. Reasons for this posterior site-specific suppression of tooth formation are not clear. The l2 peg-shape anomaly exceeded a 10-fold elevation in expression in the PDC sample, a very highly significant increase from normal prevalence. The findings are consistent with a hypothesis that the anomalies of tooth agenesis, tooth-size reduction, and PDC are biologic covariables in a complex of genetically related dental disturbances.

Adolescent↗
PubMed1996

Site-specificity of tooth agenesis in subjects with maxillary canine malpositions.

Tooth agenesis (hypodontia) was studied in two samples of nonsyndromic subjects possessing either maxillary canine-first premolar transposition (Mx.C.P1; N=43, M9:F34) or palatal displacement of the maxillary canine (PDC; N=58, M21:F37). Agenesis of permanent teeth was identified by x-ray film analysis. Significantly elevated tooth-agenesis frequencies were noted in both samples. Statistically significant differences between the Mx.C.P1 and PDC samples were found in locations of absent teeth, indicating site-specificity of tooth agenesis associated with these canine malpositions. In Mx.C.P1, agenesis of third molars (M3) occurred at a near-normal rate (19%) while maxillary lateral incisor (I2) agenesis showed a thirteen-fold increase (26%). In PDC, the prevalence rate for associated M3 agenesis was 40%, twice the normal rate, while I2 agenesis was 3%, a slight elevation of no statistical significance. These new findings may warrant a hypothesis of anteroposterior site-specific shift in the occurrence of tooth agenesis, associated genetically or epigenetically with distinct anomalies of maxillary canine position and possibly other abnormalities.

Adolescent↗
PubMed1995

Correlations between familial refractive error and children's non-cycloplegic refractions.

We examined the spherical equivalent refractions of 237 subjects who had been seen four or more times in a longitudinal study of refractive development in normal children. We employed both photorefraction and autorefraction using a Canon R1 autorefractor. We performed an analysis of variance (F-test for Lack of Fit) to determine the significance of a linear regression in fitting these refractions against three different measures of familial refractive status. One measure included only the number of myopic parents, a second took into account the number of hyperopic parents, and a third included the refractive states of extended genetic relatives. We found no significant correlation between photorefractive data and familial refractions; however, we did find significant, albeit weak, correlations between all measures of familial refractive status and infrared autorefractions of their children. A linear relationship between autorefractive data and overall familial refractive state was found to be most significant. Linear regression of children's autorefractions against a measure of parental myopia and hyperopia was less significant, while a linear model fitting only a measure of parental myopia was least significant, in addition to showing other non-linear trends. We attribute the failure to find a significant correlation between parent and offspring refractions using children's photorefractive data to vignetting by the apparatus and to the short distance of the fixation target. We believe the significant correlation patterns found with the autorefractor reflect the inheritance patterns of parental and familial refractive states.

Adolescent↗
PubMed1995

Classification of maxillary tooth transpositions.

Tooth transposition is a severe disturbance of tooth order and eruptive position, involving certain teeth, that may occur at any of several specific sites in the mouth. Published cases of transposition involving maxillary teeth were gathered from worldwide sources to study, identify, and classify these occurrences of orthodontic interest. With a sample of 201 cases and on the basis of anatomic factors, five types of maxillary tooth transpositions were discerned: canine--first premolar (Mx.C.P1), 143 cases; canine--lateral incisor (Mx.C.I2), 40 cases; canine to first molar site (Mx.C to M1), 8 cases; lateral incisor--central incisor (Mx.I2.I1), 6 cases; and canine to central incisor site (Mx.C to I1), 4 cases. As a benefit from this large-scaled study of an uncommon anomaly, new analyses are presented on cause and treatment aspects for each of these five classes of maxillary tooth transpositions.

Child↗
PubMed1995

Selected aspects of the art and science of facial esthetics.

The historical aspects of facial esthetics and its role in orthodontic teachings and practice are traced to their origins in classical art. Related discussions include the failure of "divine proportions," the ascent of the Class II facies, and the influence of 19th century pseudoscience. Today, the treatment of facial form for a diverse society requires a tolerant sense of esthetic pluralism. Moreover, advances in neuroscience and psychology have extended understanding of the biological basis of variation in facial expression and judgment. The nature of oral esthetics was examined through quantitative studies of the smile line. Significant sexual dimorphism was found, ie, the gingival smile line (GSL) appears to be a female lineament and the low smile line seems to be a male lineament. Further results indicated that the GSL is associated with several facial characteristics, including anterior vertical maxillary excess, and the muscular capacity to raise the upper lip significantly higher than average on smiling. Other variables associated with GSL are statistically significant increases in overjet, interlabial gap at rest, and overbite. The gingival smile line is not necessarily objectionable esthetically and it will normally diminish with age. However, the treatment of choice for the GSL patient with an uncoached complaint is orthognathic surgery and orthodontics.

Adolescent↗
PubMed1995

Large bowel-to-pelvic sidewall adhesions associated with chronic pelvic pain.

STUDY OBJECTIVES: To assess retrospectively the prevalence of colon-to-pelvic sidewall adhesions associated with pelvic pain or pelvic endometriosis, and to evaluate prospectively their prevalence compared with controls. DESIGN: A retrospective review of all patients undergoing laparoscopy for chronic pelvic pain between August 1992 and September 1993; and abased on a power analysis, a prospective comparison of women undergoing laparoscopy for chronic pelvic pain with those undergoing laparoscopy for tubal sterilization between October 1994 and December 1995. SETTING: A university-associated teaching hospital. PATIENTS: Fifty women in the retrospective portion, and 30 women (15 in each group) in the prospective portion. MEASUREMENTS AND MAIN RESULTS: Of the 50 women undergoing laparoscopy for pelvic pain, 47 (94%) had either right- or left-sided colon-to-sidewall adhesions, and these adhesions were more common than any other type of intraabdominal adhesion, 94% versus 58%. Thirty-eight (76%) of these women had visual and 25 (50%) histologic evidence of endometriosis. The prospective study revealed that women with pelvic pain had a higher rate of colon-to-sidewall adhesions than controls (93.3% vs 13.3%) and a correspondingly higher rate of visualized endometriosis (73.3% vs 6. 7%). Right-sided paracolic adhesions were both more common than left-sided adhesions (87.7% vs. 46.7%) and were more often extensive than minimal (46.7% vs 6.7%). CONCLUSIONS: Colon-to-sidewall adhesions occur in the majority of patients with chronic pain, whereas they are an uncommon finding in the general population. The lateral gutters are dependent regions of the abdominal cavity that are susceptible to the spread of peritoneal endometriosis or other inflammatory processes, and should be evaluated at diagnostic laparoscopy for chronic pelvic pain.

Chronic Disease↗
PubMed1994

The palatally displaced canine as a dental anomaly of genetic origin.

Palatal displacement of the maxillary canine tooth is a positional variation thought generally to develop as a result of local factors, such as retained deciduous canines, anomalous permanent lateral incisors, or dental crowding. This article contributes biologic evidence pointing to genetic factors as the primary origin of most palatal displacements and subsequent impactions of maxillary canine teeth. Data gathered from multiple sources are integrated to support a genetic etiology for the palatally displaced canine (PDC) on the basis of five evidential categories: 1. Occurrence of other dental anomalies concomitant with PDC; 2. Bilateral occurrence of PDC; 3. Sex differences in PDC occurrence; 4. Familial occurrence of PDC; 5. Population differences in PDC occurrence. From analysis of available evidence, the PDC positional anomaly appears to be a product of polygenic, multifactorial inheritance.

Cuspid↗
PubMed1993

Angle versus Case.

Explore the source record for details and available documents.

History, 19th Century↗
PubMed1993

Maxillary canine-first premolar transposition, associated dental anomalies and genetic basis.

Maxillary canine-first premolar (Mx.C.P1) transposition, an uncommon dental anomaly involving positional interchange of the two teeth, was studied using a sample of 43 subjects with the abnormality. Data were recorded on sidedness, sex, race, tooth agenesis, and peg-shaped maxillary lateral incisors for each case. Mx.C.P1 transposition occurred bilaterally in nearly one-quarter of the sample and favored female expression (sex ratio, M1:F3.8) and left-side occurrence (61% of unilateral cases). Familial occurrence was noted, as was a predilection for white subjects. Tooth agenesis (excluding third molars) and/or peg-shaped maxillary lateral incisors accompanied Mx.C.P1 transposition in 49% (21) of the subjects, four to ten times the normal rate of occurrence. Data from this study and the analysis of previously published cases provided strong evidence that Mx.C.P1 transposition is a disturbance of tooth order and eruptive position resulting from genetic influences within a multifactorial inheritance model.

Adolescent↗
PubMed1993

Comparison of dental arch dimensions in children from southern and northern Finland.

The purpose of this survey was to determine whether children in northern Finland had different dental arch dimensions from children in southern Finland. Dental casts of 9-year-old healthy children from Helsinki (southern Finland) and from Oulu and Sodankylä (northern Finland) were measured. Each group contained 41 subjects who had received no orthodontic treatment. The children from Sodankylä and Oulu had narrower dental arches and greater palatal heights than those from Helsinki. The lengths and perimeters of dental arches were significantly shorter in the children from Sodankylä than in those from Helsinki. We suggest these differences could have resulted from adaptation to different climatic conditions, affecting modes of breathing.

Cephalometry↗
PubMed1993

A time for change of tooth numbering systems.

Tooth numbering provides dentists with an essential shortcut in clinical record-keeping. Today, three systems are favored worldwide: the Zsigmondy/Palmer system, the universal system, and the FDI two-digit system. Histories of these tooth numbering methods are traced, and the strengths and deficiencies of each are discussed. The FDI two-digit system-used throughout the world, but not in the USA-is the only method that makes visual sense, cognitive sense, and computer sense. It deserves consideration by American dentists as our official tooth numbering system.

Dentition↗
PubMed1992

Some vertical lineaments of lip position.

This study was performed to elucidate quantitatively upper lip-tooth-jaw relativity in the vertical dimension. Values for five linear dentolabial measurements were generated from male (n = 42) and female (n = 46) reference samples. In addition, three vertical skeletofacial dimensions and two vertical dental dimensions were recorded. A significant sexual dimorphism was found in the vertical lip-tooth-jaw relationship: the upper lip of the female subjects was positioned on average 1.5 mm more superiorly at maximum smile than the upper lip of the male subjects (p less than 0.01). High smile lines appeared to be a female lineament, and low smile lines appeared to be a male lineament. There was a significant sex difference in upper lip length: the male subjects exhibited a longer upper lip than the female subjects (p less than 0.001). The mean difference was 2.2 mm. A similarly significant male-female difference was seen in the skeletal maxillary height measurement: the male sample showed a 2.2 mm mean vertical maxillary increase over the female sample (p less than 0.001). Furthermore, a significant difference was found between the clinical crown height of the maxillary central incisors in the male and female subjects of comparable ages: the male group had longer central incisor crowns (p less than 0.01).

Adolescent↗