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Biomedical subjects

A Sandham

Publications and source records attributed to A Sandham.

At least 19 recordsLinked to original sources
PubMed2006

A new method for the 3D measurement of postoperative swelling following orthognathic surgery.

OBJECTIVE: To describe a new method for measuring facial swelling following orthognathic surgery using a 3D laser-scanning device. DESIGN: Prospective clinical trial. Setting and Sample Population -- University Dental Hospital, Wales College of Medicine, Biology Life and Health Sciences. Three subjects requiring bi-maxillary orthognathic surgery were recruited for the study. EXPERIMENTAL VARIABLES: Laser-scanned images of the subjects were obtained under a reproducible and controlled environment with two Minolta Vivid 900 (Osaka, Japan) optical laser-scanning devices assembled as a stereo-pair. A set of left and right scanned images was taken for each subject and each scan took an average of 2.5 s. 3D laser scans were recorded over six time periods (T1 -- pre-surgical scan, postoperatively: T2 -- 1 day, T3 -- 1 week, T4 -- 1 month, T5 -- 3 months and T6 -- 6 months). OUTCOME MEASURE: Facial scans from different time periods were overlaid onto the baseline (T6) facial scan to determine the reduction and changes in swelling following orthognathic surgery. RESULTS: The results showed that swelling could be accurately quantified following surgery. Furthermore, there was a significant reduction in the amount of swelling 1 month postoperatively. Furthermore, the facial morphology returned to approximately 90% of the baseline facial scan at 3 months. CONCLUSION: The 3D laser-scanning device and the method described was a reliable and accurate measure of facial swelling following surgery.

Adult↗
PubMed2001

An assessment of orthodontic treatment using occlusal indices.

This retrospective study was carried out to assess the need for orthodontic treatment and the standard of treatment provided by the Government Dental Clinic in Singapore. The materials for this study comprised the pre-treatment and post-treatment study models as well as the clinical notes of 194 patients who were consecutively debanded over a three-month period in 1996. The pre- and post-treatment models were assessed using the Index of Orthodontic Treatment Need (IOTN) and the Peer Assessment Rating (PAR) index. The results indicated that a large proportion (81.4%) of the cases were treated with extractions. The majority of the cases were treated by upper and lower fixed appliances. Treatment was completed, on average, in 21 visits spread over 2.1 years. The result also demonstrated that the majority of the patients had genuine need for treatment for both dental and aesthetic reasons. Eighty-two percent of patients fell into the category of "need" for treatment based on dental health grounds. The mean PAR score reduction was 77%, indicating a high standard of treatment.

Adolescent↗
PubMed2000

Effectiveness and duration of two-arch fixed appliance treatment.

The aims of this study were to determine the effectiveness and duration of single-phase two-arch fixed appliance treatment and to evaluate factors that may influence these two variables. Data were collected from 177 consecutively completed cases at the Orthodontic Department, Government Dental Clinic, Singapore, during a three-month period. Pre-treatment and post-treatment models were assessed using the Peer Assessment Rating (PAR) index. The result showed that two-arch fixed appliance treatment reduced the malocclusions on average by 77.80 per cent over a period of 25 months. Multiple regression techniques revealed that 22 per cent of the variability in treatment effectiveness could be explained by the pre-treatment PAR score, the age at the start of treatment, the frequency of office visits and whether or not the treatment involved extractions. The variation in treatment duration was due to the frequency of office visits, the pre-treatment PAR score and whether or not the treatment involved extractions or headgear.

Adolescent↗
PubMed1999

A duty of quality.

Explore the source record for details and available documents.

Delivery of Health Care↗
PubMed1999

Surface laser scanning of the cleft palate deformity--validation of the method.

Innovations in laser technology have led to the development of three-dimensional surface laser digitisation techniques capable of registering surface topology accurately. The clinical application of this technology in cleft palate documentation requires validation of the technique. This study determined the reliability of the surface laser scanning technique and assessed the reliability of interactive three-dimensional landmark localization. Original and duplicate plaster models of an infant with a complete unilateral cleft lip and palate were digitised with the Cyberware 3030R-HIREZ surface laser scanner. Seven anatomic landmarks were marked permanently on the palatal surface of the duplicate model only, which acted as visual cues for landmark localisation. Each model was scanned ten times serially, and ten composite three-dimensional images were obtained for each. On-line interactive computer landmark localisation permitted the assessment of variance for the x, y and z coordinates of each landmark. The precision of the laser scanning technique was found to be less than 0.06 mm in all three axes. Anatomic landmarks with the clearest visual cue were the least variable after ten rounds of scanning. Significant differences existed between visually aided and non-aided landmark localisation (P < 0.05). While landmarks could be localised repeatedly without the aid of a visual marker, landmarks well defined by a clearly visible visual cue on the three-dimensional image were more reliable.

Cleft Palate↗
PubMed1993

Vertical height differences in subjects with severe dental wear.

The present study aims to determine differences in vertical facial dimensions as a result of severe dental wear. The sample consisted of 35 subjects (mean age 48.4 years) who had advanced dental wear recognized by loss of more than one-third of the estimated original incisor crown length. The control group comprised 40 subjects (mean age 26.1 years) with acceptable occlusions and no signs of severe generalized tooth wear. Lateral skull radiographs were taken for both the study sample and the control group with the mandible in the maximum retruded position, from which measurements were made using a digitizer. The results showed no significant differences for total face height (n-gn) between the groups (P > 0.05) although for the study sample, upper face height was greater (P < 0.05) and lower face height was smaller (P < 0.05). Smaller values for tooth length were found in the wear sample, with the mean differences in tooth length being 5.0 mm for upper incisors and 3.3 mm for lower incisors. The overbite was smaller in the wear sample and the lower incisor position differed from controls in this group. It is concluded that the differences in face height together with differences in lower incisor position through dento-alveolar development contribute to maintenance of total facial height, so compensating for loss of vertical height through severe dental wear.

Aging↗
PubMed1993

Orthodontic practice in The Netherlands.

Free movement of dental practitioners between the United Kingdom and The Netherlands presents no registration problems. Difficulties still exist for the registration of orthodontic specialists, but these should be solved with the introduction of the specialist register in Britain. Information is presented here which describes the mechanism for registration.

Accreditation↗
PubMed1993

Nasal septal deformity in unilateral cleft lip and palate.

The present study is part of a larger rhinomanometric investigation to determine the type and extent of nasal septal deformity in subjects with repaired unilateral complete clefts of the lip and palate (UCLP). The cleft sample consisted of 21 subjects (mean age 16.4 years). A control group consisted of 30 subjects (mean age 13.1 years). The rhinomanometric measurements in this study have been previously reported (Sandham and Solow, 1987) and showed that bilateral nasal resistance did not differ significantly between the cleft sample and the controls. Unilateral measurements of nasal resistance showed higher valves for the cleft side than the noncleft side (p < .001). Nasal septal deformity was scored for anomaly type and severity, by direct visual observation of each nasal compartment. The results showed that nasal septal deviation occurs more frequently in subjects with cleft lip and palate than controls (p < .001). The cartilaginous nasal tip, like the maxillary nasal spine, deviated to the noncleft side because of its dependency for directional control on the maxillary crest, and it projected into the nasal aperture of the noncleft side. The most frequent deviation of the bony septum was to the cleft side, and this not only involved the valve area but also a broader area opposite the turbinates.

Adolescent↗
PubMed1991

Nasal airflow characteristics in a normal sample.

The present study aims to describe the characteristics of nasal airflow in terms of the relative contributions of laminar and turbulent flow to the total pressure drop across the nose. The sample comprised 20 dental students with no history of nasal airway obstruction. Rhinomanometric data were recorded by a Mercury NR6 rhinomanometer with a Rohrer programme by the anterior and posterior methods after decongestion. Rohrer equation coefficients were calculated for each respiratory cycle. Method errors ranged from 6.3 to 9.3 per cent of sample variances. At a threshold of 75 Pa, average unilateral NAR was about 300 Pa/l/s and average bilateral resistance about 250 Pa/l/s. Analysis of the Rohrer equation data showed average coefficients of laminar (k1) and turbulent (k2) flow of 113 and 807 in unilateral breathing, indicating a predominance of turbulent flow. In bilateral breathing a switching of airflow characteristics occurred, with k1 and k2 coefficients of 147 and 348 indicating a marked reduction in the turbulent component of flow. It is suggested that Rohrer equation coefficients might provide information about nasal airflow which are physiologically more meaningful than conventional resistance calculations based on a single point on the rhinomanometric pressure-flow curve.

Adult↗
PubMed1988

Cranial base and cleft lip and palate.

Previous studies do not agree on relationships between cleft palate and the cranial base. This study comparing normal and cleft lip-and-palate samples finds no significant difference in cranial base angle, but significantly shorter clivus length in the cleft sample.

Adolescent↗
PubMed1988

Repeatability of head posture recordings from lateral cephalometric radiographs.

The mechanisms that control facial growth are still not known. One method for studying these mechanisms is the careful analysis of subjects with normal and aberrant growth patterns using standardized lateral cephalometric radiographs. It has been shown in normal subjects that head posture is related to facial development and that changes in head posture are influenced by changes in nasal respiratory resistance (NRR). In the determination of these associations it is therefore important to assemble cephalometric data from lateral skull radiographs that have been standardized for position as well as for natural head posture. The study demonstrates that a reproducible head posture position exists that can be recorded with a method error of only a few degrees.

Adolescent↗
PubMed1988

Rhinomanometric method error in the assessment of nasal respiratory resistance.

Reproducibility of nasal resistance recording is important if meaningful clinical and investigative data are to be assembled. The present study investigated by duplicate determination, reproducibility of anterior (unilateral) and posterior (bilateral) recordings of nasal respiratory resistance (NRR) for 12 subjects. Improved accuracy was achieved with frequent use of a calibration device and visual feedback for the patient. The results show that the recordings are reproducible with a small method error of between 13.6 Pascals/cc/sec x 10(3) and 41.5 Pascals/cc/sec x 10(3).

Airway Resistance↗
PubMed1987

Nasal respiratory resistance in cleft lip and palate.

The present study aimed to determine the nasal respiratory resistance (NRR) in subjects with cleft deformity of the lip and palate. The cleft sample was subdivided into cleft lip (N = 15) (mean age 13.4 years, median age 14 years), cleft palate (N = 19) (mean age 12.7 years, median age 12 years), and unilateral cleft lip and palate subjects (N = 27) (mean age 16.4 years, median age 16 years). A control group consisted of 38 patients (mean age 14.4 years, median age 12 years) attending for orthodontic diagnosis. Respiratory resistance was determined by a Mercury rhinomanometer, which was calibrated dynamically before each session. Subjects were given 0.1% xylometazoline hydrochloride half an hour before each session. Resistance was determined unilaterally by the anterior method as well as bilaterally by the posterior method. The results showed that the bilateral nasal resistance did not differ significantly between the cleft samples and the controls. Unilateral measurements of nasal resistance showed higher values for the cleft side than for the noncleft side, both in the cleft lip (CL) and the unilateral cleft lip and palate (UCLP) samples (p less than 0.001). In the cleft palate sample as well as in the controls, unilateral nasal resistance did not differ between the two sides.

Adolescent↗
PubMed1986

Cervical vertebral anomalies in cleft lip and palate.

A survey was made of the upper cervical vertebrae in children with cleft lip and palate in order to determine the prevalence of cervical vertebral anomalies. The cleft sample consisted of 105 patients attending for orthodontic treatment. It was subdivided into cleft lip (CL), cleft palate (CP), unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP) subgroups. A control was comprised of 120 orthodontic patients. The cervical vertebral anomalies were classified into two types, posterior arch deficiency (PAD) and fusion anomalies (FUS). The results confirmed that the cervical vertebral anomalies occurred significantly more often in the cleft sample (13%) than in the controls (0.8%), p less than 0.001. The total prevalence of cervical vertebral anomalies was similar in the four cleft sub-samples, but the occurrence of each of the two types of cervical vertebral anomalies showed a more differentiated pattern. Posterior arch deficiency occurred significantly more often in cleft palate (CP), (16%) than in controls p less than 0.001, but fusions did not occur more frequently in any cleft groups than in controls.

Axis, Cervical Vertebra↗
PubMed1985

Embryology of the middle third of the face.

This article compares the midface appearance of two histological sections, one an embryo at the 6 mm stage of development and another at the 28 mm stage. It demonstrates the considerable cellular differentiation and development that takes place, and suggests that this area is liable to anomalies if the rapid, sequential and considerable amount of growth in this area is disturbed by inherited or environmental factors.

Cell Differentiation↗
PubMed1985

Embryonic head posture and palatal shelf elevation.

During embryonic and fetal stages of human development, elongation and straightening of the neck occurs. Authors have suggested that the resulting change in head posture lifts the lower border of the mandible from the pericardial region, so allowing jaw movements to assist the withdrawal of the tongue from between the palatal shelves. This aids elevation of the palatal processes prior to fusion. This paper reports on histological sections of 28 mm twin embryos which demonstrate that palatal elevation can take place in the absence of elongation and straightening of the neck, demonstrated by observation of existence of cephalic, pontine and cervical neural flexure of the brain.

Female↗