Search PubMed⌕ Search

Biomedical subjects

S Peck

Publications and source records attributed to S Peck.

At least 19 recordsLinked to original sources
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↗
PubMed1996

The effects of meal schedule and quantity on problematic behavior.

We present 2 case examples that illustrate the effects of meal schedule and quantity on displays of problematic behavior. In the first example, self-injury displayed by a toddler with severe developmental delays was maintained by parent attention, but only when he was satiated for food. When he was food deprived, self-injury decreased but did not appear to be differentiated across low or high social conditions. In the second example, crying and self-injury displayed by an elementary-aged girl with severe disabilities were correlated: Both behaviors were associated with food quantity, and neither behavior was responsive to social stimuli. These results replicate and extend previous findings demonstrating that meal schedule or food quantity can affect problematic behavior. In the present studies, brief functional analyses of aberrant behavior provided useful information for interpreting distinct patterns of behavior displayed by each child. We discuss these results in terms of the concept of establishing operations.

Behavior Therapy↗
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↗
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↗
PubMed1994

Functional analysis of separate topographies of aberrant behavior.

We conducted a functional analysis of distinct topographies of aberrant behavior displayed by 4 clients. We first analyzed the behaviors in an aggregate fashion and then separated the behaviors to formulate hypotheses about the maintaining variables for each behavior. The procedures were used in a two-phase experiment. During Phase 1, two extended functional analyses were completed, one in an inpatient unit and one in a special education classroom. During Phase 2, two brief functional analyses were completed in an outpatient clinic. Results indicated that hypotheses of separate functions for distinct behaviors can be generated using both extended and brief functional analyses when the results are graphed in the aggregate and are separated by response topography. The results also suggest that these methods can improve the accuracy of data interpretation and treatment selection.

Adult↗
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

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↗
PubMed1992

The gingival smile line.

A comparative study was performed to examine the nature of the gingival smile line (GSL), a specific dentolabial configuration characterized by the exposure of maxillary anterior gingiva during a full smile. Five soft-tissue, three dental and three skeletal variables were selected, measured and reported for a GSL sample (n = 27) and a reference sample (n = 88), both consisting of North American white orthodontic patients with a median age of 14.4 years. The results indicated that the capacity to project a gingival smile was related to: anterior vertical maxillary excess and the muscular ability to raise the upper lip significantly higher than average when smiling. Other variables significantly associated with GSL were greater overjet, greater interlabial gap at rest, and greater overbite. Factors that did not appear associated with the GSL phenomenon were upper-lip length, incisor clinical crown height, mandibular plane angle, and palatal plane angle. Clinical aspects of GSL were discussed.

Adolescent↗