Changes in the faces and smiles of patients with dentofacial deformities

In recent years, new materials and more versatile techniques have made it possible for increasingly complex dentofacial deformities to be treated by multidisciplinary teams, with maxillofacial surgeons and orthodontists as the core team members. This lecture will demonstrate the treatment of these challenging cases. Through teamwork, maxillofacial surgeons and orthodontists can bring back smiles to these patients.postprin

Orthodontic treatment need and quality of life

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Comprehensive cephalometric analyses of 10 to 14-year old southern Chinese

Aims: (Part 1) To review the orthodontic literature and assess which cephalometric methods were the most frequently used, and (Part 2) provide comprehensive cephalometric reference values for 10 to 14-year old southern Chinese. Materials and Methods: (Part 1) The cephalometric methods used in the orthodontic literature over a ten-year period (1999-2008) were investigated. (Part 2) The material comprised lateral cephalometric radiographs of a random sample of 200 males and 205 females 12-year old southern Chinese in Hong Kong. The radiographs were digitized twice with the Computer Assisted Simulation System for Orthognathic Surgery (CASSOS) program. Referenced values for 10-, 11-, 13- and 14-year old were obtained by extrapolation of data from measurements of templates of longitudinal sample of Swedish. Results: (Part 1) The four most frequently used cephalometric methods were those devised by Björk, Jacobson, Pancherz and McNamara. (Part 2) Reference population values for those four methods of 12-year old southern Chinese children were collected from three of our previous publications, and for the McNamara analysis expanded to include 10 to 14-year old children. At the age of 12-year there were statistically-significant gender differences for the majority of the cephalometric variables based on linear measurements, varying from -0.4 to +0.8 standard deviation (SD)-scores, and about half of the angular measurements, varying from -0.4 to +0.4 SD-scores. Conclusion: Four cephalometric methods presented over a 10-year period were more commonly used than the other cephalometric methods. The use of specific cephalometric standards of those four methods for southern Chinese, separate for gender, seem to be justified.published_or_final_versio

PTHrP and Cbfal expression in condylar cartilage during pubertal growth

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Assessment of orthopedic treatment of class III malocclusion Using P.A.R. index

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Modified Bjork analysis of lateral head radiographs of southern Chinese

Aim: To establish cephalometric norms for the modified Björk’s cephalometric analysis in southern Chinese children, and compare them to those of a matched Caucasian sample. Materials and Methods: The material comprised lateral cephalometric radiographs of a random sample of 200 males and 205 females 12-year-old southern Chinese, and an additional sample of 43 males and 43 females 12-year-old British Caucasian children in Hong Kong. The radiographs were digitized twice with the Computer-Assisted Simulation System for Orthognathic Surgery (CASSOS) program. Results: The results showed that there were statistically significant ethnic differences for 15 out of the 17 cephalometric variables (P<0.05-0.001). There were statistically significant ethnic differences for 11 variables in males (P<0.05-0.001) and 15 variables in females (P<0.05-0.001). The size of the statistically significant gender differences varied from -0.4 to 0.8 (P<0.05-0.001) in SD scores for Chinese and from 0.5 to 0.6 (P<0.01) for Caucasian. The size of the observed statistically significant ethnic differences varied from -1.7 to 1.3 (P<0.05-0.001) in SD scores for female and from -1.6 to 1.0 (P<0.05-0.001) for male. Conclusion: Cephalometric norms for the modified Björk’s cephalometric analysis in southern Chinese children were established. The use of specific standards for Chinese and separate for gender, for the modified Björk’ cephalometric analysis seems to be justified.published_or_final_versio

Effective age for application of orthopedic maxillary protraction

Abstract no. 1374published_or_final_versio

New standards for permanent tooth emergence in Australian children

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: Published standards for permanent tooth emergence in Australian children are 40 years old. The aim of this study was to present new data on the timing and sequence of permanent tooth emergence in a large sample of Australian children and to compare the findings with those of earlier studies. Methods: Records of a randomly selected sample of 8676 children, aged between 4 to 16 years, who had attended the clinics of the South Australian Dental Service were scanned optically and coded to provide the data for this study. A logistic regression analysis enabled median times of emergence, together with percentile ranges, to be calculated for each tooth, except third molars, in boys and girls. Comparisons were made between the sexes and with previously published values. The frequencies of occurrence of emergence polymorphisms for different tooth pairs were also computed. Results: The earliest teeth to emerge in both boys and girls were the central incisors and first molars, whereas the second premolars and molars and maxillary canines tended to be last to emerge. The mandibular teeth tended to precede the corresponding maxillary teeth in emergence in both sexes. Tooth emergence was advanced in girls compared with boys, averaging 4.5 months in the maxilla and 5.3 months in the mandible. In general, emergence times of children in the present sample were later than those reported previously for Australian children. The most common emergence polymorphism in the maxilla involved the canine and second premolar, whereas common polymorphisms in the mandible were noted for the central incisor and first molar, canine and first premolar, and the second premolar and second molar. Conclusions: Given that they have been collected relatively recently from a large sample of children, the new data reported in this paper can now be used as standards when assessing permanent tooth emergence of Australian children.J Diamanti, GC Townsen

Masticatory muscle pain before, during, and after treatment with orthopedic protraction headgear: A pilot study

Protraction headgear has been used in conjunction with a palatal expansion appliance to correct Class III malocclusion with maxillary deficiency and/or mandibular prognathism. In general, 800 gm of orthopedic force is used to protract the maxilla, and 75% of this force is transmitted to the temporomandibular joint (TMJ) area via the mandible. The effect of this heavy intermittent force on the TMJ has not been reported in the literature. The objectives of this study were to determine the level of masticatory muscle pain and EMG activity in patients treated with maxillary protraction headgear. Ten patients with skeletal Class III malocclusion whose treatment plan called for maxillary protraction headgear treatment participated in this study. Nocturnal masticatory muscle activity was determined using a portable electromyographic (EMG) recording device. Subjects wore the EMG device 14 nights before treatment, 14 nights during treatment, and 14 nights 1 month after active treatment. Masticatory muscle pain level was determined by muscle palpation, scored on a scale of 0 to 3 each period, according to the method of Gross and Gale. The examiner followed a sequence outlined by Burch to examine the masticatory muscles. Results showed no significant differences for masticatory muscle activities before, during, and after treatment. Only a few patients experienced level 1 masticatory pain during treatment. None of the patients experienced masticatory muscle pain 1 month after treatment. These results demonstrate no significant increase in masticatory muscle activity or muscle pain associated with orthopedic treatment using maxillary protraction headgear.published_or_final_versio

Cephalometric comparisons of Chinese and Caucasian surgical class III patients

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