Biomedical subjects

Chris Johnston

Publications and source records attributed to Chris Johnston.

8 recordsLinked to original sources

PubMed2007

A cephalometric study of Class II malocclusions treated with mandibular surgery.

INTRODUCTION: Class II malocclusion is often associated with retrognathic mandible. Some of these problems require surgical correction. The purposes of this study were to investigate treatment outcomes in patients with Class II malocclusions whose treatment included mandibular advancement surgery and to identify predictors of good outcomes. METHODS: Pretreatment and posttreatment cephalometric radiographs of 90 patients treated with mandibular advancement surgery by 57 consultant orthodontists in the United Kingdom before September 1998 were digitized, and cephalometric landmarks were identified. Paired samples t tests were used to compare the pretreatment and posttreatment cephalometric values for each patient. For each cephalometric variable, the proportion of patients falling within the ideal range was identified. Multiple logistic regression analysis was performed to identify predictors of achieving ideal range outcomes for the key skeletal (ANB and SNB angles), dental (overjet and overbite), and soft-tissue (Holdaway angle) measurements. RESULTS: An overjet within the ideal range of 1 to 4 mm was achieved in 72% of patients and was more likely with larger initial ANB angles. Horizontal correction of the incisor relationship was achieved by a combination of 75% skeletal movement and 25% dentoalveolar change. An ideal posttreatment ANB angle was achieved in 42% of patients and was more likely in females and those with larger pretreatment ANB angles. Ideal soft-tissue Holdaway angles (7 degrees to 14 degrees ) were achieved in 49% of patients and were more likely in females and those with smaller initial SNA angles. Mandibular incisor decompensation was incomplete in 28% of patients and was more likely in females and patients with greater pretreatment mandibular incisor proclination. Correction of increased overbite was generally successful, although anterior open bites were found in 16% of patients at the end of treatment. These patients were more likely to have had initial open bites. CONCLUSIONS: Mandibular surgery had a good success rate in normalizing the main dental and skeletal relationships. Less ideal soft-tissue profile outcomes were associated with larger pretreatment SNA-angle values, larger final mandibular incisor inclinations, and smaller final maxillary incisor inclinations. The use of mandibular surgery to correct anterior open bite was associated with poor outcomes.

Adolescent↗

PubMed2006

Class III surgical-orthodontic treatment: a cephalometric study.

INTRODUCTION: In this retrospective study, we investigated treatment outcomes in Class III surgical-orthodontic patients. METHODS: Records of 151 consecutively completed Class III surgical-orthodontic patients (overjet, 0 mm or less) were obtained from 87 consultant orthodontists in the United Kingdom. Pretreatment and posttreatment cephalometric radiographs were analyzed. RESULTS: Bimaxillary surgical patients (75%) had more negative initial ANB-angle values and smaller initial SNA-angle values than those treated with single-jaw mandibular surgery. Mandibular surgery patients (15%) had greater pretreatment mandibular prominence (SNB angle) than maxillary patients. Maxilla-only patients (10%) had lower negative initial overjet values than bimaxillary patients. An overjet within the ideal range of 1 to 4 mm was achieved in 83% of the patients. Logistic regression identified no predictors of ideal overjet outcome. SNB angle was corrected to within the ideal range of 75 degrees to 81 degrees in 44% of the patients. This was less likely in those treated with maxillary surgery only and larger initial SNB-angle values. An ideal posttreatment ANB angle (1 degrees to 5 degrees) was achieved in 40% of the patients and was more likely in those with bimaxillary surgery, lower negative pretreatment ANB angles, and presurgical orthodontic extractions in the maxillary arch. Ideal posttreatment unadjusted Holdaway angles (7 degrees to 14 degrees) were achieved in 59% of the patients and were more likely when single-jaw mandibular surgery was used. Incisor decompensation was incomplete in 46% of the patients and was associated with mandibular arch extractions. CONCLUSIONS: Surgical-orthodontic treatment had a high success rate in normalizing the overjet and soft-tissue profile to within ideal ranges in Class III patients. Bimaxillary surgery was the most frequently used procedure and was associated with an increased likelihood of an ideal correction of the anteroposterior skeletal discrepancy.

Adolescent↗

PubMed2006

Self-reports of psychosocial functioning among children and young adults with cleft lip and palate.

OBJECTIVE: A cross-sectional study was employed to determine the psychosocial effects of cleft lip and/or palate among children and young adults, compared with a control group of children and young adults without cleft lip and palate. PARTICIPANTS: The study comprised 160 children and young adults with cleft lip and/or palate and 113 children and young adults without cleft lip and/or palate. All participants were between 8 and 21 years of age. OUTCOME MEASURES: Psychological functioning (anxiety, self-esteem, depression, and behavioral problems) was assessed using validated psychological questionnaires. Happiness with facial appearance was rated using a visual analog scale. Social functioning, including experience of teasing/bullying and satisfaction with speech, was assessed using a semistructured interview. RESULTS: Participants with cleft lip and/or palate reported greater behavioral problems (p < .001) and more symptoms of depression (p < .01); they were teased more often (p < .001) and were less happy with their facial appearance (p < .01) and speech (p < .001), compared with controls. There were no significant difference between subjects with cleft lip and/or palate and subjects without cleft lip and/or palate in terms of anxiety (p > .05) or self-esteem (p > .05). Having been teased was a significant predictor of poor psychological functioning, more so than having a cleft lip and/or palate per se (p < .001). CONCLUSIONS: Teasing was greater among participants who had cleft lip and/ or palate and it was a significant predictor of poorer psychosocial functioning. Children and young adults with cleft lip and/or palate require psychological assessment, specifically focusing on their experience of teasing, as part of their routine cleft care.

Adolescent↗

PubMed2005

The influence of mandibular prominence on facial attractiveness.

This study examined the attractiveness of facial profiles. One hundred and two social science students (28 males and 74 females) rated the attractiveness of a series of silhouettes with normal, Class II or Class III profiles. A random sequence of 10 images included an image with the Eastman normal SNB value of 78 degrees, and images with SNB values of 2.5, 5, 7.5 and 10 degrees above and below normal. A duplicate image in each sequence was used to assess reproducibility. The participants scored the attractiveness of each image and also indicated whether they would seek treatment if each image was their own profile. The profile with the normal SNB angle of 78 degrees was rated as the most attractive. Attractiveness scores reduced as the mandibular profile diverged from the normal SNB value. The +5 degree profile (SNB = 83 degrees) was rated as significantly more attractive than the -5 degree profile (SNB = 73 degrees; P = 0.004). No other significant differences between the scores for Class II and Class III profile pairs of equal severity were found. At 10 degrees below the normal SNB (Class II), 74 per cent of the sample would elect to have treatment, while 78 per cent would elect to have treatment at 10 degrees above the normal SNB (Class III).

Adolescent↗

PubMed2005

The psychosocial effects of cleft lip and palate: a systematic review.

This systematic review examined the published scientific research on the psychosocial impact of cleft lip and palate (CLP) among children and adults. The primary objective of the review was to determine whether having CLP places an individual at greater risk of psychosocial problems. Studies that examined the psychosocial functioning of children and adults with repaired non-syndromal CLP were suitable for inclusion. The following sources were searched: Medline (January 1966-December 2003), CINAHL (January 1982-December 2003), Web of Science (January 1981-December 2003), PsycINFO (January 1887-December 2003), the reference section of relevant articles, and hand searches of relevant journals. There were 652 abstracts initially identified through database and other searches. On closer examination of these, only 117 appeared to meet the inclusion criteria. The full text of these papers was examined, with only 64 articles finally identified as suitable for inclusion in the review. Thirty of the 64 studies included a control group. The studies were longitudinal, cross-sectional, or retrospective in nature.Overall, the majority of children and adults with CLP do not appear to experience major psychosocial problems, although some specific problems may arise. For example, difficulties have been reported in relation to behavioural problems, satisfaction with facial appearance, depression, and anxiety. A few differences between cleft types have been found in relation to self-concept, satisfaction with facial appearance, depression, attachment, learning problems, and interpersonal relationships. With a few exceptions, the age of the individual with CLP does not appear to influence the occurrence or severity of psychosocial problems. However, the studies lack the uniformity and consistency required to adequately summarize the psychosocial problems resulting from CLP.

Adult↗

PubMed2003

Localizing ectopic maxillary canines--horizontal or vertical parallax?

This study compared the use of horizontal parallax (HP) and vertical parallax (VP) radiography for localizing ectopic maxillary canines (EMCs). The true positions of 43 EMCs were determined using the operative notes and subsequent study models following exposure and eruption. Thirty-four palatal and nine buccal EMCs were included in the study. Six experienced orthodontists examined the radiographs of the EMCs and were asked to localize each EMC using VP and HP on separate occasions. The examiners recorded a diagnosis of 'unsure' in 12 per cent of cases using VP and in 5 per cent of cases using HP. The level of agreement of the diagnoses with the true position of the EMCs was significantly greater for HP. Eighty-three per cent of EMCs were correctly located with HP while only 68 per cent were correctly located with VP (P < 0.05). The diagnostic sensitivity for palatally placed canines was significantly greater for HP (88 per cent) than for VP (69 per cent). Both techniques performed poorly when used to localize buccal EMCs, with HP and VP each having a sensitivity of only 63 per cent. It is concluded that HP is superior to VP in diagnostic accuracy, and that two peri-apical radiographs or one peri-apical and one anterior occlusal radiograph are the radiographs of choice for localizing EMCs.

Adolescent↗

PubMed2002

The Aesthetic Component of the Index of Orthodontic Treatment Need validated against lay opinion.

This study aimed to determine the threshold of aesthetic impairment where orthodontic treatment would be sought by a sample of lay people. Using the 10-grade Aesthetic Component (AC) scale of the Index of Orthodontic Treatment Need (IOTN), 215 university students selected the level of aesthetic impairment that represented the point at which they would seek orthodontic treatment. Only nine (4.3 per cent) of the respondents recorded a threshold grade beyond grade 5 in the AC. The AC photograph grade 4 was found to be the most commonly selected threshold photograph. Subjects who visited the dentist every 6 months were more likely to choose a threshold photograph closer to the attractive end of the scale than those who visited their dentist less frequently (P < 0.01). This study, using lay people rather than dental health professionals, suggests that as currently used the AC does not reflect society's aesthetic expectations. The results indicate that when using the AC of the IOTN the 'no need for treatment' category should be grades 1-3 of the AC, rather than grades 1-4.

Adolescent↗

PubMed2002

The influence of maxillary gingival exposure on dental attractiveness ratings.

This study examined the influence of maxillary gingival display on the attractiveness ratings awarded by lay people. One hundred and twenty university students (94 females, 26 males) were shown seven photographs of a male and seven photographs of a female subject, each with varying levels of gingival display ranging from -2 to +4 mm. Attractiveness ratings were recorded on a 10-point numerical scale for each of the photographs. The photographs where the full height of the incisors were revealed and no gingival tissue was visible (0 mm of gingiva) were rated as the most attractive. Gingival display of more than 2 mm was rated as progressively less attractive. Linear regression analysis revealed that those students who had received orthodontic treatment rated the photographs representing the female student as more attractive than those representing the male (P < 0.05).

Adult↗