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Biomedical subjects

J C Aird

Publications and source records attributed to J C Aird.

11 recordsLinked to original sources
PubMed2001

Functional regulator treatment of Class II division 1 malocclusions.

This controlled retrospective study aimed to identify the contribution of skeletal and dental changes in the correction of Class II division 1 malocclusions using Fränkel's functional regulator II (FRII), with reference to a concurrently recruited control group. One hundred and thirty-eight patients with Class II division 1 malocclusions were identified, those accepting treatment forming the study group and those declining treatment the control group. The study group (n = 70) were treated with a Fränkel appliance. Pre- and post-treatment observation cephalometric radiographs were analysed and compared. Mean values for both skeletal and dental variables in the control group were remarkably consistent throughout the study period; however, this masked individual variations in this group. The skeletal variables in the study group that showed statistically significant differences from the control group were SNB, ANB, BaNA and ANS-Me, but none of these was sufficiently large to be regarded as clinically significant. Dental variables showed clinically and statistically significant differences, including a 10 degree reduction in UI-Max and 3.1 degree increase in LI-Mand. The Fränkel appliance was thus found to be effective in producing desirable occlusal and dental changes in the majority of patients treated.

Adolescent↗
PubMed1999

Skeletal and dental changes following the use of the Frankel functional regulator.

The purpose of this study was to assess the relative contributions of skeletal and dental components in correction of Class II division 1 malocclusions when treated with Frankel's functional regulator (FR). This was a retrospective study involving analyses of pre- and post-treatment cephalograms of 63 Class II division 1 patients treated with the FR to demonstrate the relative maxillary, mandibular, incisor, and molar movements during treatment compared with normal growth within a control group of untreated 39 Class II division 1 cases drawn from the same demographic population. All cephalograms were digitized and subjected to a Pitchfork analysis, which measured individual anteroposterior skeletal and dental changes during the period of study. It was shown that the FR was effective in treating Class II division 1 cases with the studied group being corrected to a clinically acceptable overjet and overbite of 2-3 mm. The majority of the correction came from dental movements, the most significant being the retroclination of the upper incisor teeth (mean 4.1 mm, 95 per cent CI +/- 0.44) and proclination of the lowers (mean 2.2 mm 95 per cent CI +/- 0.57). As regards skeletal correction, the most significant contribution was the restraint of normal maxillary forward growth (mean -0.2 mm, 95 per cent CI +/- 0.62) with forward mandibular growth not being a significant factor.

Cephalometry↗
PubMed1997

Bonded orthodontic retainers: the wire-composite interface.

The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. An in vitro model was developed to simulate the forces encountered at the wire/composite interface. No significant difference was detected between different multistrand wire types and diameters with regard to retention in composite. Wires were placed in one of three groups according to surface characteristics identified with scanning electron microscopy. Increasing the thickness of composite overlying the wire increased the force required to detach the wire from the composite. Thickness of composite greater than 1.0 mm overlying the wire may give little clinical advantage. Greater force was required to detach the wire from Concise Orthodontic (3M Unitek) than any other composite tested. In vitro abrasion resistance testing found Heliosit Orthodontic (Vivadent) and Right On (TP Orthodontics, Inc.) to have poor abrasion resistance, whereas Concise Orthodontic and Transbond (3M Unitek) had abrasion resistance comparable with restorative composites. Clinical recommendations are made based on these findings.

Adhesiveness↗
PubMed1996

Index of Oral Cleanliness (I.O.C.). A new oral hygiene index for use in clinical audit.

Although plaque control influences orthodontic treatment planning, treatment progress and outcome, current national orthodontic clinical audit software does not include an assessment of oral hygiene. This paper presents the development of the Index of Oral Cleanliness, a new simple rapid measure of oral hygiene, and describes its validation and reliability by comparison with the Silness and Loe plaque index in an unselected group of adolescents. It is concluded that the Index of Oral Cleanliness provides a valid quantitative method of scoring oral hygiene, with advantages for use in routine clinical practice.

Adolescent↗
PubMed1995

Ex vivo bond strength of adhesive precoated metallic and ceramic brackets.

Compared with conventional adhesive systems, adhesive precoated (APC) are reported to have advantages in clinical use. The ex vivo bond strength to human premolar teeth of metallic and ceramic APC brackets was compared with that of identical brackets bonded with Transbond (3M Unitek) light cured orthodontic adhesive, and patterns of failure were examined. There was no significant difference (P > 0.05) in mean bond strength between metallic brackets bonded with the two systems. Ceramic brackets bonded with Transbond had significantly higher (P < 0.05) mean bond strength and failure more normally occurred at the composite/enamel interface when compared with APC ceramic brackets and metallic brackets. Following debonding no enamel damage was observed with either APC or conventionally bonded ceramic brackets.

Analysis of Variance↗
PubMed1988

Fracture of polycarbonate brackets--a related photoelastic stress analysis.

In clinical use polycarbonate edgewise bracket designs, patterned on metallic predecessors, have demonstrated slot-wing fracture. A preliminary two-dimensional photoelastic stress investigation is described in which two bracket designs, without angles in the edgewise slot component, are subjected to simulated palatal root torque mechanics.

Dental Stress Analysis↗
PubMed1987

Fracture of polycarbonate edgewise brackets: a clinical and SEM study.

Fracture experience and fracture form of polycarbonate edgewise brackets, were assessed in a clinical study using four force controlled mechanical systems. The incidence and types of bracket fracture were investigated macroscopically and by Scanning Electron Microscopy (SEM). It was concluded that the engagement of both round and square archwires and stainless steel ligaturing were aetiological factors in bracket fracture.

Dental Cements↗