Arch length discrepancy can be resolved either by extraction or expansion. Normally, the choice of the clinician is founded on evidence-based treatment outcome reports. The adverse effect related to either approach is considered carefully before deciding. In the adult patient, the retraction of soft tissues consequent to extractions may be undesirable. Also, the deep bite may be difficult to correct if incisor proclination is to be avoided. Expansion has been reported to elicit gingival dehiscences. This is a report of a borderline case where the crowding is resolved acceptably through extreme expansion, but without any adverse periodontal effects.

Efficiency of treatment mechanics has been a major focus throughout the history of orthodontics. Self-ligating brackets were developed on the premise that elimination of ligature ties creates a friction-free environment and allows for better sliding mechanics. It is expected that the self-ligating bracket will reduce the treatment time. This study was designed to compare the effectiveness and efficiency of Damon self-ligating (SL) brackets to those brackets ligated with either steel ligatures or elastomeric 'O' rings. Not only treatment time and the number of appointments needed were addressed, but the quality of the treatment outcome was also assessed. American Board of Orthodontics (ABO) grading criteria for models and panoramic radiographs were employed. Additionally, a nine-question survey was sent to the 215-patients in this study (108 Damon, 107 conventionally-ligated) to elicit their perceptions of how their orthodontic treatment progressed and finished. The results showed that patients treated with Damon SL brackets had significantly lower treatment times, required significantly fewer appointments, and had significantly higher ABO scores than those treated with conventionally-ligated edgewise brackets. There were no significant differences in Damon or non-Damon ABO scores with respect to gender. Damon patients over the age of 21 had significantly higher ABO scores. Conversely, the non-Damon patients under the age of 21 had significantly higher ABO scores. For pre-treatment Angle classification, no significant differences were noted. Patient responses showed that Damon patients perceived their treatment time as being shorter than expected. It appears that faster orthodontic treatment can be better as measured by the ABO criteria.

A number of laboratory studies have shown very low levels of archwire friction for self-ligating brackets when compared to conventional ligation methods. However, justifiable reservations have been expressed as to the in vivo relevance of these findings. This study was designed to compare treatment efficiency with conventional fully programmed brackets and Damon SL self-ligating brackets. Thirty consecutively finished cases treated by the author with Damon SL brackets were compared with 30 matched cases treated by the author with conventional brackets. Parallel studies quantified the incidence of technical problems with Damon SL brackets and with conventional ligatures and also the chairside time required for ligation/slide closure and ligature removal/slide opening with these two bracket types. The Damon SL cases required an average of four fewer months and four fewer visits to be treated to an equivalent level of occlusal regularity as measured by the PAR scores.

Insulin-like growth factors are mediators of growth hormone and are believed to also stimulate growth independently. Insulin-like growth factor I (IGF-I) null mutant mice exhibit a lower rate of skeletal growth compared with their wild-type (control) littermates. Although their general body dimensions seem proportionate, their heads appear shortened with a blunt nose compared with the controls. The aim of this project was threefold: 1) to investigate whether differences in shape/form exist between the craniofacial skeleton of the IGF-I null mutant mice and their control littermates by using three techniques; 2) to determine whether the three techniques yield similar, different, or complementary information regarding the size and shape of specimens; and 3) to investigate whether the histological sections obtained from the craniofacial skeleton exhibit any differences between the two groups. Thirty adult male mice, 12 mutant and 18 wild type, obtained from 11 litters were examined. Lateral and superio-inferior radiographs of their head were analyzed by the procrustes, the macroelement, and the traditional cephalometric techniques. Later, the animals were processed for routine histological examination. The IGF null mutant mice demonstrated a generalized decrease of craniofacial size (43-64% of the normal adult size) and a non-allometric change of shape when compared with their wild-type littermates. While the mandible did not exhibit any shape changes, the facial and cranial areas demonstrated prominent changes. Examination of histological sections did not reveal any structural difference between the two groups at the adult stage. Furthermore, procrustes and macroelement techniques offer a more complete, detailed, and comprehensive description of the specimens compared.

Our aim was to develop a simple, non-invasive method that could be used to objectively record cranial symmetry over time. We utilized this new method to investigate the relationship between torticollis and progressive plagiocephaly. From 1995 to 1999, the head shapes of 419 torticollis patients and 1 211 normal children were evaluated. We used Ezeform strip, a splint material, to make a permanent ring of the head circumference. Each head ring was recorded, scanned, and analyzed. An asymmetric index (AI) was designed. Double-blind comparisons of clinical assessment with AI values demonstrated a good agreement. Asymmetry of the cranium was found with similar frequency in torticollis and normal babies up to 12 months old. After 1 year of age, the deformity persists in patients with torticollis into their adolescence, while the normal group shows increased symmetry. This new recording system offers an objective and efficacious methods for following the natural history of cranial asymmetry.

It is suggested that osteopontin may promote osteoclast binding to resorptive sites by interacting with the alphavbeta3 receptor on osteoclasts. However, the role of osteopontin in functional remodeling of bony structures remains unclear. The present study was conducted to examine the distribution of osteopontin on the condyle and explore the role in condylar remodeling in growing rats using an immunohistochemical method. Twenty Wistar strain male rats aged 7, 14, 28 and 56 days were used. In 7- and 14-day-old rats, no immunoreaction to osteopontin was detected in the cartilage cells. In 28-day-old rats initiating mastication, the thickness of condylar cartilage was decreased abruptly as compared to the younger rats. High immunoreaction to osteopontin was found in the cytoplasm of hypertrophic chondrocytes and on the trabecular bone surfaces of primary spongiosa adjacent to the osteoclasts or chondroclasts. The immunoreactions to osteopontin in the cytoplasm of hypertrophic chondrocytes were less in 56-day-old rats than in 28-day-old rats. It is shown that the alteration in mechanical loading on the mandibular condyle due to functional changes from weaning to mastication correlates with the localization of osteopontin in growing rats. Furthermore, it is suggested that osteopontin may stimulate osteoclastic resorption of calcified matrix by mediating the attachment of osteoclasts and/or chondroclasts during growth-related functional remodeling of the condyle.

The displacement of teeth into areas with substantial atrophy of the alveolar ridge or through the maxillary sinus has been considered a major limitation. Bone formation can, however, be generated if the orthodontic appliance can produce the necessary strain distribution along the entire periodontal ligament. The aim of this case report is to illustrate how bone formation can accompany mesial bodily movement of maxillary and mandibular molars. The necessary strain distribution was generated by the rational use of segmented mechanics. The use of superelastic Ni-Ti springs allows the application of low and constant forces over a wide range of deactivation, thus providing a uniform strain in the periodontium. The result of those appliances is highly predictable and side effects can be minimized effectively.

Movement of teeth through anatomic limitations, such as the maxillary sinus, can be a reliable therapeutic protocol if suitable force systems are used. We report here the outcome of a treatment based on this concept. The patient exhibited pneumatization of the maxillary sinus resulting from earlier extractions. She was treated using an endosseous implant inserted in the retromolar region to serve as orthodontic anchorage and a T-loop appliance fabricated from TMA wire to bodily move an upper second premolar through the sinus. After 6 months, at the end of the displacement, a titanium implant was inserted in the alveolus of the moved tooth and a single crown restoration was placed. The premolar moved through the sinus maintaining its support apparatus and bone. At the end of treatment the implant used for anchorage was still osseointegrated.

It is well known that the size of the condyle is different between males and females in humans. It has also been documented that ovariectomy (OVX) and orchiectomy (ORX) influence the remodeling of the condylar head in experimental animals. However, influences of sex hormones on the condyle in terms of its breadth have not been examined. With these considerations, this study was designed to examine the breadth of the mandibular condyle in OVX and ORX mice by histomorphometry 8 weeks after surgery. In the OVX mice, the condylar breadth was significantly larger than in the controls, while no significant differences in the breadth were found between the ORX mice and the controls. The thickness of the condylar cartilage layers exhibited similar findings to the breadth of the condyle. On the contrary, the trabecular bone volume was significantly smaller in the OVX and ORX mice than in the corresponding controls, and the difference was more substantial in female mice than in the males. These findings emphasize that a reduction of sex hormone levels, induced by OVX and ORX, significantly influences condylar morphogenesis.

In this paper we tried to analyse in quantitative terms the differences in trabecular structure of human mandibles 8, 10 and 12 weeks old. The analysis was performed on decalcified Sirius-red stained trabeculae, photographed in polarised light. The data obtained from Fourier transforms of scanned pictures were evaluated by discriminant analysis to show the differences between the analysed stages of development. Also, various parts of the mandible were compared because the clinical experience shows that the frequency of pathological changes is different in different parts of mandible bone. The complexity of trabecular structure of bone samples was measured by fractal dimension. It is concluded that this quantitative approach is reliable and, in the future, could be used for physiological and pathological analyses of bone biopsies.

The purpose of this study was to elucidate the nature of human craniofacial growth by means of finite element method (FEM), and to compare the results with the current concept derived from morphometric studies with roentgenographic cephalometry (RCM). Lateral cephalograms were taken of 20 males and 20 females, and traced on acetate paper. On the tracing, the craniofacial complex was divided into seven areas or elements. Growth analysis was executed with FEM for changes in the size and shape of each area during six developmental periods from 4 to 18 years old. The size change in the male group exhibited a peak from 10 to 12 years old for the cranial base and upper facial skeleton, from 8 to 10 years old for the maxillary complex, and from 12 to 14 years old for the mandible. On the other hand, in the females, the size change was almost invariable from 4 to 12 years old and completed suddenly at 12 years old, which was earlier by a few years than in the males. An interesting finding is that changes in the size and shape were the most substantial in the maxillary complex, followed by those in the mandible, and the smallest in the cranial base and upper facial skeleton. It is shown that growth of the cranial base lasted up to 14 years old and the maxillary complex exhibited the greatest growth changes in the size among various anatomic structures. These findings may provide a new concept of human craniofacial growth, somewhat different from the previously established principles by RCM.

Hard tissue palatal dimensions and shape in 29 boys and 32 girls (mean age 14 years) and 30 men and 35 women (mean age 20 years), all with a complete permanent dentition including the second molars, and free from respiratory problems, were analyzed. Palatal landmarks were digitized with a computerized 3D instrument, and their coordinates were used to derive a mathematical model of palatal form. Palatal shape (size-independent) was assessed by a four-order polynomial in the sagittal and frontal plane projections. Palatal dimensions in the frontal and sagittal planes were computed, and compared between ages and sexes by two-way factorial analyses of variance. The effect of age on palatal shape was different in the two sexes: while in females the curves in both the frontal and sagittal planes were practically superimposed, in males the youngest subjects had somewhat 'lower' curves than the oldest subjects. Sex had a significant (p<0.05) effect for all variables. Age was significant only for palatal slope in the sagittal plane (p<0.01), and for raphe inclination in the horizontal plane (p<0.05). For all variables but palatal length in the sagittal plane, a significant (p<0.01) sexxage interaction was found: while in males all linear variables were larger in adults than in adolescents, the reverse was found in females. Overall, while in adolescent females palatal form appeared to have already attained adult characteristics, in males some modifications between adolescence and young adulthood were measured. These modifications should be taken into consideration as a possible factor of relapse after orthodontic treatment.

This study aimed at determining the relative genetic and environmental impact on a number of well-known cephalometric variables in twins. In order to find a clue in the heritability pattern of some dentofacial characteristics and on the expected limits of the therapeutic impact on the dentofacial subparts they are representing. Cephalograms were collected from 33 monozygotic and 46 dizygotic twins, who did not undergo any orthodontic treatment. Nineteen linear and four angular variables were selected all representing a different definite subpart of the dentofacial complex. The reproducibility of the measurement of most of the linear variables was very high. A genetic analysis using model fitting and path analysis was carried out. First, data were checked on the fulfilment of the conditions for genetic analysis in twins reared together. The results show that the genetic determination is significantly higher for vertical (72%) than for horizontal (61%) variables. As far as the genetic component is concerned, all variables selected seem to be inherited by additive genes, except for mandibular body length, which was determined by dominant alleles. Sex differences in genetic determination were found for the anterior face height, showing a significantly higher genetic component for boys (91%) than for girls (68%). For the angular measurements, no genetic influence was found: only environmental influences common to both members of each pair could be demonstrated.