Adolescent patients' experience with the Carriere distalizer appliance.

AIM: To examine adolescent patients' experience with the Carriere Distalizer Appliance (CDA) and compare it with that of the Forsus Fatigue Resistant Device (FFRD). MATERIALS AND METHODS: A survey was administered to 42 patients treated with the CDA and 70 patients treated with the FFRD. Amount of time required to become accustomed to the appliance, how many patients experienced side effects as well as the degree of discomfort were explored. RESULTS: The overall experience with the device was significantly better for the CDA group than for the FFRD group. Both groups felt that delivery and removal of the appliance was quick and easy, the appliance was noticeable to some extent, and the majority became accustomed to it within two weeks with a maximum of one month. In general, associated discomfort and effects on daily life and activities were less for the CDA group than for the FFRD group. Side effects decreased over time for both groups, often more so for the CDA group. The major side effects experienced by the CDA group were difficulty eating and sore teeth, and these improved significantly over time. Soreness from the appliance rubbing on the cheek or lip was significantly less for the CDA group. CONCLUSION: The CDA appears to be more comfortable, offers a more positive overall experience, and has fewer negative comfort-related side effects compared to FFRD.

On the non-existence of compensatory tooth size interaction in a contemporary human population.

Compensatory tooth size interactions between early and later developing teeth within the same tooth class were empirically evaluated in a sample of 125 study casts of Caucasoid children. Mean buccolingual and mesiodistal diameters for first and second molars, pre-molars, and incisors were calculated, and those first developing teeth that were either larger of smaller than the mean were identified. Pearsonian correlation coefficients and chi-square tests revealed highly significant positive correlations between smaller of larger early developing teeth and their later developing neighbors. This total lack of compensatory tooth size interaction was also confirmed when outsized teeth (larger of smaller than one standard deviation from the mean) were used. Similar results were obtained when tooth size was corrected for arcade length, hence allowing for the rejection of Sofaer's model of compensatory tooth size interaction.

Oral health status of the Lengua Indians of Paraguay.

The dental and oral health status of 202 Lengua Indians of Paraguay was determined using DMT, Russell's PI and the Greene & Vermillion OHIS. Caries experience in young Lenguas was shown to be positively associated with exposure to Western culture. Mean DMT increased from 8.36 for 15-19 yr-olds to 9.44 in 20-24 yr-olds. For the 25-29 yr age group the DMT was 9.10 whilst 30-34 yr-olds had a mean DMT of 8.67. The mean DMT of 9.64 for 35-40 yr-olds increased to 9.84 for the over 40 age group. Oral hygiene and periodontal status were found to be similar to those reported in other Chaco Indian groups.

Restitution of facial form in a patient with hemifacial microsomia. A case report.

Hemifacial microsomia involves unilateral underdevelopment of the ear, mandible and associated structures. This report describes an approach to early surgical restoration of function to improve growth, illustrated with a case report.

Occluso-cranial correlates of attrition in a preliterate population. A cross-sectional study.

Evaluation of dental casts of 202 living Lengua Indians from Paraguay finds progressive reduction in overjet with age, but no Class III or indication of altered relationship of mandible to cranial base.

Adaptation of the bioprogressive philosophy to use brackets with .022" slots.

The Bioprogressive orthodontic treatment philosophy is traditionally associated with the use of brackets that have .018" slots. Proponents of the Bioprogressive philosophy suggest this slot configuration largely because they believe that lighter wires provide force levels that are within the biological limits of the periodontal support system. At the same time, the principles of orthodontic anchorage advocated by the Bioprogressive philosophy depend on careful torque control of both molar and anterior teeth. It is possible and sometimes advisable to use wires designed for use in brackets with .018" slots, in brackets with .022" slots. Under these circumstances, the thinner wires may not provide sufficient control over torque moments to develop the required degree of molar anchorage. This article suggests that with the use of certain wires, and with minor modifications to the shapes of arches, that the use of brackets with .022" slots need not conflict with many of the important principles of orthodontic treatment advocated in the Bioprogressive philosophy.

A longitudinal evaluation of extraction versus nonextraction treatment with special reference to the posttreatment irregularity of the lower incisors.

A tendency exists in contemporary orthodontics to pursue a completely non-extraction philosophy. Moreover, it has been shown that the extraction versus non-extraction debate is still with us. Controversy exists as to which treatment decision will eventually lead to orthodontic stability. It is thus imperative to conduct investigations on long-term changes of the dentition in both treatment regimens. The present study serves as an example of such a longitudinal study. A random sample, inclusive of both extraction and non-extraction treatments, was examined with respect to long-term stability and an assessment was made as to whether one treatment option favors success over the other. It was concluded that the correct initial treatment choice will not only lead to correction of the malocclusion, but will also ensure clinically acceptable stability with no significant differences between extraction and non-extraction treatments.

The cephalometric analysis of Cercopithecus aethiops.

A Steiner-based cephalometric study of 46 adult Vervet monkeys was undertaken using craniometric points as closely correlated to those in the human as possible. On tracings of each cephalogram 13 measurements were recorded. The results were statistically analysed. Whilst the monkey face does vary individually this variation is apparently much less than is that of the human face. It is possible that the positions of the monkey incisor crowns bear a relatively constant relationship to the soft tissue profile. The establishment of some cephalometric norms for the Vervet monkey may be useful for future growth studies.

The dentition of the Lengua indians of Paraguay.

The crown morphology of 202 dental casts from living Lengua Indians is described and compared with other Amerind, Melanesian, and Caucasoid samples. The Lengua dentition shows a high Mongoloid component with little effects of possible European admixture, thus supporting the theory that despite early Franciscan and Jesuit attempts at missionization, much of the Paraguayan Chaco has remained genetically and culturally relatively intact well into the present century. A finding of note was the apparent sexual dimorphism of the Carabelli cusp, which questions earlier assumptions that no correction for sex need be made in population studies when dealing with this trait. Since mandibular canines show proportionately less wear in the canine distal accessory ridge area than maxillary canines, the value of the incidence of this trait in population and microevolutionary studies is questioned.

Maxillary canine retraction, periodontal surgery, and relapse.

Extraction spaces closed during the course of orthodontic therapy tend to re-open, whereas orthodontically rotated teeth are prone to relapse. One of the major causes of spaces opening between teeth is the supra-alveolar soft tissues which do not always adapt to the new tooth positions. Seven patients requiring extraction of upper first premolar teeth as part of their orthodontic treatment were selected for this study. Tattoo marks were placed in the attached gingivae close to the upper canine teeth. The canines were then retracted orthodontically across the extraction spaces. The left side was designated the control side and the right side the experimental side. Immediately after completion of retraction, the attached gingiva was surgically detached from the canine teeth on the experimental sides. The canines on both sides were retained in their new positions for 8 weeks following space closure. The amount of relapse or recoil of the gingivae was measured. In this study the gross gingival changes were similar to those described by Atherton and Kerr, Atherton, Edwards. The tattoo marks moved distally with the retracted canines. The amount of gingival movement was similar on both experimental and control sides and ranged between 49.4 percent and 82.4 percent of the retraction distance. Very little recoil or relapse of the gingivae occurred following surgical detachment from the canines. The results of this study indicate that the gingivae appear to adapt to the new tooth position and that relapse of canines retracted across extraction sites in the maxilla is not necessarily caused by the supra-alveolar soft tissues.

The relationship between ortho head posture and head posture measured during walking.

Murphy, Preston, and Evans recognized the dynamic nature of head posture and developed instrumentation capable of measuring and recording this posture in a continuous manner. The aim of the current project was to use the newly developed instrumentation to determine whether the difference is statistically significant between the mean natural head ortho posture, measured in a controlled manner, and the mean dynamic head posture obtained during 5 minutes of walking activity in an experimental situation. The mean ortho head posture and the mean walking head posture were measured in each of 30 men. The differences between these two sets of mean head postures were statistically significant (p < or = 0.05). In 23 persons, the mean walking head posture was tipped backward relative to the mean natural head ortho position.

Resistance to nasal airflow related to changes in head posture.

The relationship] between mode of respiration, cranial posture, and craniofacial morphology has been the subject of many articles in recent years. Some authors postulate that mouth breathers extend their heads backward in an effort to increase airway patency. The purpose of the present study was to determine whether artificially induced extended head posture decreases the resistance to nasal airflow. The experimental sample comprised fifteen male students with normal vertical facial proportions and no histories of chronic mouth breathing. In the sample, head posture was assessed by measuring the craniovertical angle by means of an angle finder. Nasal resistance units were calculated from the parameters of nasal airflow and differential pressure across the nasal airway during the complete respiratory cycle using an equation analogous to Ohm's law. Readings were obtained in both the normal and 10-degree extended head posture position, and the results were compared. No association could be found between an extended head posture position and a decreased resistance to nasal airflow.

The development of instrumentation for the dynamic measurement of changing head posture.

Cranial posture and its possible relationship to the morphology of the skull has been studied in some detail, as have the relationships between cranial posture and such functions as respiration and jaw movements. To date, cranial posture has been assessed mainly with techniques that give static interpretations of the angular relationships between intracranial and extracranial reference lines. The present project was undertaken to develop a system of instruments capable of the continuous measurement and recording of cranial posture for extended periods of time. A number of aspects of this system were tested. The results indicate that the experimental array of instruments measures head posture accurately over a defined range of cranial movement. This new technique should make it possible to measure cranial posture in a more dynamic and physiologic manner.

An evaluation of two methods used to determine the centre of gravity of a cadaver head in the sagittal plane.

A suitable method to locate the centre of gravity of the head is not available at present. Precise location of that centre will help in the understanding of aspects of cranial balance and what effect skeletal changes, following for example orthognathic surgery, may have on head posture. The objective of this research was to use a mechanical (empirical) method, based on accepted laws of physics, to determine the centres of gravity of cadaver heads in the sagittal plane and to compare these positions with those generated by a computer programme. The two methods located the centre of gravity in the same region but at a different position in each corresponding head. These differences were statistically significant (p < 0.01). It is likely that improved computer techniques together with modern three dimensional imaging methods will be able to locate the centre of gravity of a head in a living subject.

Patterns of dental wear in the Lengua Indians of Paraguay.

Wear patterns were examined on dental casts of 202 living Lengua Indians from the Chaco area of Paraguay. Consideration was given to the development of the molar helicoidal plane, age-related changes in occlusal attrition, coalescence of dentine exposures, interproximal attrition, and erupted crown height. This study lends support to Osborn's theory of the helicoidal plane development by showing that attrition enhances rather than modifies posteruption molar occlusal planes. The rate of interproximal attrition was found to slow down with the eruption and functional initiation of the third molars. Sinuous and cavo-convex interproximal contact areas that are generated with age, however, appeared to be less abrasion resistant than straight surfaces, hence leading to an increase in interproximal attrition rates with advanced age. Maximum crown height reduction occurred between the ages of 20 and 40 years in central incisors, canines, and first molars. Kruskal-Wallis tests and log linera models failed to demonstrate significant sexually dimorphic or antimeric differences in wear patterns of Lengua teeth.

Provision of "comprehensive dental care" in various dental schools.

The purpose of this survey was to solicit information about comprehensive dental care (CDC) programmes in various dental schools. Seventy-four schools responded to a questionnaire which sought information about a range of topics pertaining to CDC. The 19 questions used were categorized under the following headings: implementation and success; physical nature of clinics; staffing; and, student involvement. The diverse nature of the responses is thought to be an expression of differing philosophies and of the presence of numerous constraints to the introduction of CDC. The various approaches to CDC make it very difficult to gauge the relative merits of the many systems reported. It appears from this study that departments will continue to play an important role in preparing students to participate in CDC programmes and that it would be safer to introduce students to CDC during the final year of study.

Provision of "comprehensive dental care" in various dental schools.

The purpose of this survey was to solicit information about comprehensive dental care (CDC) programs in various dental schools. Seventy-four schools responded to a questionnaire that sought information about a range of topics pertaining to CDC. The 19 questions used were categorized under the following headings: implementation and success, physical nature of clinics, staffing, and student involvement. The diverse nature of the responses is thought to be an expression of differing philosophies and of the presence of numerous constraints to the introduction of CDC. The various approaches to CDC make it very difficult to gauge the relative merits of the many systems reported. It appears from this study that departments will continue to play an important role in preparing students to participate in CDC programs and that it would be safer to introduce students to CDC during their final year of study.

Postural response of the head to bite opening in adult males.

The postural position of the head is a resultant of muscular interactions and reactions, influenced by gravity and functional demands. In order to investigate possible postural adaptation of the head to an altered functional status, a standard degree of jaw opening was produced by mechanical means in the mouths of thirty young males. There was an extension of the head associated with the jaw separation. In the majority of cases, a recovery to approximately the original posture resulted within 1 hour after removal of the bite-opening device.

Hemifacial microsomia. A case report.

A case of hemifacial microsomia is presented. The mandible, temporomandibular joint, zygomatic arch and temporal region were reconstructed by means of skull bone grafts when the patient was 6 years old, a relatively early age. This corrective surgery has effectively restored normal mandibular function, and in so doing may encourage more acceptable development of the affected facial structures.