Guiding Occlusal development with functional appliances
A mathematical study of anterior dental relations: Part II, incisor and canine overjet
Application of a case-based expert system to Orthodontic diagnosis and treatment planning: A review of the literature
Functional appliances: A mortgage on mandibular position
Complications of orthognathic surgery
Second permanent molar extraction and late lower arch crowding: A ten-year longitudinal study
A genetic aetiology for some common dental anomalies: A pilot twin study
Post-retention results of spring-loaded posterior bite-block therapy
A family case report: Disturbances in tooth form and eruption of the second premolar
Functional appliances have been used in Orthodontics since their introduction by Pierre Robin almost one hundred years ago, however, our understanding of how they bring about orthodontic correction is still limited. This article is a brief overview of their history, mode of action, advantages and disadvantages, and includes the results of a study of attempts to control and minimise their side-effects using a recent development in functional appliances: the Teuscher Appliance. This appliance combines a high-pull headgear with the activator, and is designed to reduce the often reported side-effects of functional appliances. The skeletal and dentoalveolar effects of treatment with the Teuscher Appliance on 40 consecutively-treated patients are reported and illustrated with four individual case reports.
Accepted for publication : April 1995
Aust Orthod J 1995; 14(3)133-142
A mathematical model of anterior inter-arch relations was described in a previous article. This model is modified and manipulated and, using hypothetical dental measurements, results are generated and presented. The present work continues the two-dimensional examination of anterior dental relations in the first article, the emphasis remaining on incisor and canine overjet.
Key words : Mathematics, arch form, overjet, tooth width, arc angle, occlusion, dental spacing, dental crowding, dental arch width, dental arch depth.
Received for publication : June 1995
Aust Orthod J 1995; 14(3):143-149
Computer expert systems are being utilised increasingly in medical fields to assist diagnosis and treatment planning. Traditional rule-based expert systems have some limitations when applied to orthodontic diagnosis and treatment planning. These limitations may be avoided by using a case-based system which is a particular type of expert system that uses a stored data bank of previously-treated cases to provide the knowledge for solving new treatment problems. This article reviews the use of expert systems for orthodontic diagnosis and treatment planning, outlines the rationale, processes and advantages of case-based systems, and gives examples of the application of this technology in medical fields.
Key words : Diagnosis, treatment planning, computers, expert systems
Received for publication : November 1995
Aust Orthod J 1995; 14(3):150-153
It is a popular article of faith that clinicians and academics are polar opposites. In recent years, the supposed chasm separating town and gown has been the subject of aggrieved letters to the editor and embarrassing, intemperate comments at meetings. The seemingly eternal bone of contention is the standard of proof necessary to the conduct of a rational clinical practice.
Received for publication: July 1996
Aust Orthod J 1996; 14(3):154-157
Although orthognathic surgery has now become a routine part of oral and maxillofacial surgery practice, concern and apprehension about major jaw surgery continues to plague the minds of many orthodontists faced with the prospect of referring their patients for surgery. Like all surgery, complications also occur with orthognathic procedures, most of which can be prevented by thorough planning and careful surgery. In this article a brief overview of the potential complications associated with orthognathic surgery is presented for the benefit of orthodontists involved in the management of patients undergoing combined orthodontic-surgical treatment.
Key words : Orthognathic surgery, complications, risks, review of.
Received for publication : July 1995
Aust Orthod J 1996; 14(3):158-161
The purpose of this investigation was to examine lower arch alignment in the long term following treatment by second molar extraction. Thirty subjects, treated by extraction of four second permanent molars at an average of 13.9 years, were examined five and ten years after extractions. None had any mechanical treatment in the lower arch. Twenty had some simple upper arch treatment, including, in five cases, extraction of first premolars. The changes in lower arch alignment were measured on study models. There was a small average decrease in lower arch crowding in the first five years following extraction, and little or no change in alignment in the next five years.
Key words: Second molar extraction, crowding, stability
Received for publication : February 1996
Aust Orthod J 1996; 14(3):163-167
This pilot study investigated the aetiology of various dental anomalies. Twin-pair correlations were obtained for the total number of missing, ectopic, malformed and rotated permanent teeth which were scored from panoramic radiographs of 59 monozygotic (identical) and 42 dizygotic (non-identical) twin-pairs. All monozygotic (MZ) twin correlations were greater than the dizygotic (DZ) twin correlations, suggesting a significant hereditary aetiology. A familial history of such common dental anomalies could become a valuable asset in treatment planning.
Key words : Twins, genetic factors, dental anomalies
Received for publication : October 1995
Aust Orthod J 1996 14(3):172-178
In this study, ten patients who were treated with spring-loaded posterior bite blocks (SLPBB), were evaluated over a period of two years in order to test the effects of the appliance and the incidence of relapse. Successful treatment wit SLPBB was achieved in skeletal and dental open bite cases. However, the use of acrylic bite blocks for retention during the post-treatment growth period, did not prevent relapse.
Key words : Open bite; Bite Block Therapy; Relapse
Received for publication : November 1994
Aust Orthod J 1996; 14(3):179-183
This report describes a family who demonstrated anomalies of tooth form and eruption of the lower second premolar. Observation of the second premolars remaining in the mothers and fathers dentitions included ectopic eruption with impaction and substantial spacing between the first and second premolars. Four siblings were also examined - three boys aged 15, 14 and 12 years, and one girl aged 11 years. Anomalies of the second premolar recorded in the males and female include: congenital absence, ectopic eruption with impaction, delayed eruption and spacing. Associated anomalies included congenital absence of other permanent teeth and spacing. It appears that the defect in tooth form and eruption is of a genetic origin, affecting both males and females. The condition(s) did not appear to be associated with a syndrome, and the human papilloma virus lesions noted in all family members were not considered to be related to the dental defects. This family demonstrated two anomalies of the lower second premolar: congenital absence, and disturbance in tooth eruption. The question raised by this case report is whether these two anomalies are inherited as separate traits, or whether failure of tooth eruption is a variation in expression of the same genetic factor that results in oligodontia.
Received for publication : September 1995
Aust Orthod J 1996; 14(3):168-171