Grant T. McIntyre

Secondary Alveolar Bone Grafting (CLEFTSiS) 2000–2004

Objective To determine whether alveolar bone graft outcomes for unilateral and bilateral cleft lip and palate patients have continued to improve since the reorganization of cleft services in Scotland in 2000. Design Retrospective analysis of postoperative anterior occlusal radiographs. Patients and Participants: Eighty-one of 106 patients who were eligible for alveolar bone grafting between 2007 and 2010 had suitable postoperative radiographs available. Interventions Twenty-seven percent of the patients (n = 22) had presurgical orthodontic intervention. All patients underwent alveolar bone grafting with bone harvested from the iliac crest. Main Outcome Measures The Kindelan bone-fill index was used to evaluate success. Weighted kappa statistics were used to assess intra- and interobserver reproducibility. A comparison was made with results from 2000 to 2004 to assess any improvement. Chi-square tests (or Fisher exact test) were used to determine whether outcomes differed depending on the laterality of the cleft, use of presurgical expansion, or age at bone grafting. Result Interobserver scoring agreement was good (weighted kappa = .383). Intraobserver reproducibility was greater (weighted kappas of .835 and .620). Success was achieved in 99% of bone grafts, compared with 76% in the period from 2000 to 2004 (P < .001). There was no statistically significant relationship between the laterality of the cleft (P = 1.000), use of presurgical expansion (P = 1.000), or age at time of bone grafting and outcome (P = .259). Conclusion Scottish secondary alveolar bone graft outcomes improved during 2007 to 2010 in comparison to the 2000 to 2004 results.

Does oral health promotion influence the oral hygiene and gingival health of patients undergoing fixed appliance orthodontic treatment? A systematic literature review

Objective To determine the effectiveness of orthodontic oral health promotion (OHP) upon gingival health. Data sources The Cochrane Central Register of Controlled Trials [CENTRAL (January 2005)], MEDLINE [OVID and PubMed platforms (1966 to May 2005)] and EMBASE (1966 to May 2005) were searched. A grey literature search was also conducted. Data selection Of the 218 studies identified, 37 were retrieved for detailed examination. Methodological quality was determined using a checklist and inter-rater reliability was calculated using the unweighted kappa statistic. Six randomised (RCT) and quasi-randomised controlled clinical trails (CCT) met the inclusion criteria. Data extraction Categorical data about the effect of oral health promotion on dental plaque levels and/or gingival bleeding were independently collected from the four RCTs and two CCTs by two reviewers using a data extraction proforma. Data synthesis Positive effects on plaque and/or gingival health were produced in only four of the included trials. OHP resulted in no difference being detected in two of the included trials. None of the trials that were included produced a negative effect of orthodontic oral health promotion on oral hygiene and gingival health. Direct comparison between the trials was difficult due to the heterogeneity in the outcome measures between the included studies. Conclusions • An OHP programme for patients undergoing fixed appliance orthodontic treatment produces a short-term reduction (up to 5 months) in plaque and improvement in gingival health • No particular OHP method produces a greater short term benefit to periodontal health during fixed appliance orthodontic treatment • Further studies using appropriate methods and in particular longer follow up periods are required

Posteroanterior Cephalometric Analysis of the Parental Craniofacial Morphology in Orofacial Clefting

OBJECTIVE To evaluate the parental craniofacial morphology in orofacial clefting (OFC). DESIGN Case-control posteroanterior cephalometric study. SETTING The Department of Orthodontics, University of Dundee Dental School, Scotland, United Kingdom. PARTICIPANTS Ninety-two parents from a completely ascertained sample of 286 Scottish babies with nonsyndromic OFC and 43 comparison group volunteers from the University of Dundee Dental School. MAIN OUTCOMES AND MEASURES A conventional cephalometric analysis was used to measure linear distances and their ratios, angles, and areas. Two-sample Students t tests and a discriminant analysis were applied to the data, and the clinically important statistically significant variables were identified using an accepted protocol. RESULTS Sixty-four linear distances, 10 ratios, 52 angles, and 7 areas statistically significantly differed between the parental and comparison groups (p <.01). Of these, 62 linear distances (22%), 9 ratios (45%), 41 angles (41%), and 6 areas (24%) were clinically important. Asymmetry was a feature of the results. Canonical variates analysis correctly classified 91.3% of the parental group and 90.6% of the comparison group using a series of 36 variables. CONCLUSIONS The parental craniofacial morphology in OFC differs significantly from the noncleft population. A larger superolateral face and smaller central midface and, in particular, a clinically significantly smaller maxillary width, in conjunction with skeletal asymmetry, characterize the parents of Scottish children with OFC. These features may be of morphogenetic importance in the etiopathogenesis of OFC in this ethnic group.

Crown-root shape of the permanent maxillary central incisor

This study aimed to determine whether the lateral cephalometric crown-root shape differs among the permanent maxillary central incisor in Class I, Class II division 1, Class II division 2 and Class III malocclusions and to identify the nature of any differences. Of the 499 lateral cephalograms recorded at a university orthodontic clinic during 2001, 361 satisfied the inclusion criteria. Sixty cephalograms were selected from the four malocclusion groups and were digitized in random order. The configurations of the 10 landmarks characterizing the crown-root shape of the permanent maxillary central incisor were then optimally superimposed using Procrustes algorithms. Discriminant analysis of the principal components of shape determined the incisor shape differences between the malocclusion groups. The crown-root shape of the permanent maxillary central incisor did not differ significantly among the Class I, Class II division 1, and Class III groups (P > .05); however, the crown-root shape of the Class II division 2 permanent maxillary central incisor was significantly different (P < .001) from that of the Class 1, Class II division 1 and Class III. The shape discrimination involved axial bending of the Class II division 2 incisors. Principal components 1, 2, and 3 accounted for 63% of the Class II division 2 incisor shape variance, encompassing a shorter root, a longer crown, and axial bending of the incisor, in addition to a reduced labiopalatal thickness. These shape features could precipitate the development of a deep overbite in Class II division 2 malocclusion and may limit the amount of palatal root torque during fixed appliance therapy.

Tooth size discrepancies in Irish orthodontic patients among different malocclusion groups

OBJECTIVE To determine the prevalence of tooth size discrepancies (TSDs) in an Irish orthodontic population among different malocclusion groups. MATERIALS AND METHODS From 850 pretreatment sets of orthodontic models at a university clinic, 240 were selected with 30 female and 30 male sets for each malocclusion (Class I, Class II division 1, Class II division 2, and Class III). Digital models were produced, and the mesial and distal contact points were digitized to calculate overall and anterior tooth size ratios. The differences between the male and female groups and among the malocclusion groups were analyzed using two-way analysis of variance (ANOVA) (P < .05). RESULTS A clinically significant anterior TSD (more than two standard deviations from the Bolton means) existed in 37.9% of the subjects. No differences existed in the prevalence of overall TSDs between the male and female groups (P  =  .5913) or among the malocclusion groups (P  =  .0809). For the mean anterior tooth size ratios in the male group, the values for Class III and Class II division 2 were higher than in Class II division 1, and the value for Class II division 2 was higher than in Class I (P  =  .0184). CONCLUSIONS The prevalence of anterior tooth size discrepancies in this sample of Irish orthodontic patients was 37.9%. There were no statistically significant differences in the prevalence of mean overall TSDs with regard to malocclusion or gender. In the male group, the mean anterior tooth size ratio was higher in Class III and in Class II division 2 malocclusion than in Class II division 1 and higher in Class II division 2 malocclusion than in Class I malocclusion.

Lip Shape and Position in Class II division 2 Malocclusion

OBJECTIVE To determine whether differences exist in the shape and position of the lips between Class II division 2 and Class I malocclusions. MATERIALS AND METHODS Lateral cephalometric radiographs of subjects with Class II division 2 (n = 30) and Class I (n = 30) incisor relationships were scanned at 300 dpi to produce digital images. These were subsequently digitized in random order. Twenty-one landmarks characterizing the upper and lower lips and the maxillary and mandibular central incisors were digitized. Procrustes algorithms optimally superimposed the landmark configurations to standardize size, location, and orientation. Discriminant analysis of the principal components of shape determined the differences between the Class II division 2 and Class I groups. RESULTS The shape and position of the upper and lower lips differed significantly between the Class II division 2 group and the Class I group (P < .001). Principal component (PC) 1 (46% of the variance) involved an increase in the thickness of the upper and lower lips in the Class II division 2 group. PC2 (11% of the variance) was characterized by a relatively higher lip line in the Class II division 2 group. CONCLUSIONS The shape and position of the lips differ between Class II division 2 and Class I malocclusions.

Validation of the Volumetric Measurement of a Simulated Maxillary Alveolar Bone Defect Using Cone-Beam Computed Tomography

Objective To determine the accuracy of volumetric measurement of a simulated alveolar bone defect using cone-beam computed tomography (CBCT) scans. Design Laboratory-based observational study. Setting University dental teaching hospital. Methods Scans of a dried skull with an artificially created maxillary bone defect. Main Outcome Measures The skull was scanned using an i-CAT CBCT scanner (Imaging Sciences International, Hatfield, PA) at 0.2 mm resolution. The superior and inferior aspects of the void were identified, and the volume was calculated by three-dimensional (3D) computational analysis of the CBCT scan using an algorithm created with MATLAB software (The Mathworks Inc., R2009a, Natick, MA). The skull was then scanned using micro computed tomography (micro-CT) at 0.0934 mm resolution, and the volume of the defect was determined using the Studio Max 2.2 program (Volume Graphics, 2012, Heidelberg, Germany). The process was repeated two additional times, and the volumes were compared using a two-sample t test (P < .05). To determine the interobserver reproducibility of the identification of the superior and inferior aspects of the defect, the slices chosen to represent these extremities were selected by four separate observers and the data assessed using an F-test (P < .05). Results The interobserver reproducibility of the identification of the superior and inferior boundaries of the defect was good (P = .18). The volumes computed from the i-CAT CBCT images were 4.11% lower than those computed from the micro-CT images; however, the difference was not statistically significant (P = .71). Conclusions 3D volumetric measurement of simulated alveolar bone defects using i-CAT CBCT scans is similar to the volumes determined using micro-CT.

The Parental Dentocraniofacial Phenotype—An Orofacial Clefting Microform

Objective Using the systematic review method, (1) to identify the investigations of the parental dentocraniofacial phenotype in orofacial clefting, (2) synthesize the data to derive a model of the phenotypic features that will assist in the identification of cleft morphogenes, and (3) make recommendations for the future global strategy for researching the parental craniofacial phenotype in orofacial clefting. Search Strategy The Cochrane, Medline (via PubMed and OVID platforms [1966 to December 2006]), Embase, CINAHL, and ASKSAM Orthodontic Reference Database (1950–1997) databases were searched using a combination of the following keywords: microform, parent, craniofacial, dental, and cleft. All published articles were reviewed. There were no exclusions of non-English reports. Of the 36 studies identified using this strategy, 26 met the inclusion criteria. Data Abstraction/Synthesis The statistically significant data were abstracted using a pro forma, and the methodological quality of the selected studies was evaluated using a checklist. There was considerable heterogeneity among the studies, and therefore it was not possible to synthesize the data. We were, however, able to collate the data. Results/Conclusions (1) The craniofacial phenotype possessed by parents of children with orofacial clefting is distinctive when compared with that of the noncleft population. (2) There is insufficient evidence to produce a model of the phenotypic features to assist in the search for orofacial clefting morphogenes. (3) The pattern of expression of the phenotypic features identified to date supports the contention that there are differences in the inheritance of cleft lip with or without cleft palate and isolated cleft palate. Progress in this field is affected by extreme heterogeneity in etiology of cleft lip with or without cleft palate, as well as heterogeneity in study design. (4) Subphenotyping using features such as microforms should be employed to reduce the heterogeneity and to improve the power of future genetic investigations and will also assist in clinical management and genetic counseling for families.

Asymmetry of the craniofacial skeleton in the parents of children with a cleft lip, with or without a cleft palate, or an isolated cleft palate

The objective of this study was to evaluate asymmetry of the parental craniofacial skeleton of subjects with a cleft lip, with or without cleft palate [CL(P)], and isolated cleft palate (CP). The postero-anterior (PA) cephalograms of 52 parents of children with CL(P) and 40 parents of children with CP from a sample of 196 children with non-syndromic clefts in the west of Scotland were analysed. A conventional cephalometric asymmetry analysis was used to evaluate size-related right:left asymmetry comprising eight linear distances, nine angular, and three facial area measurements. Right:left ratios of the mean values identified the direction of the asymmetry and two-sample t-tests determined statistical significance. A shape-related asymmetry analysis was also undertaken. The configurations of landmarks were optimally superimposed and scaled using Procrustes algorithms. Euclidean distance matrix analysis (EDMA) was then compared and the shape of the left and the right landmark configurations were statistically tested using a non-parametric bootstrap technique. For the parents of CL(P) children, size-related asymmetry was identified and the area of the craniofacial polygon was statistically significantly larger on the right than on the left side. EDMA detected the presence of shape-related asymmetry (T statistic = 1.304; P = 0.003). For the parents of CP children, although size-related asymmetry was identified, EDMA did not identify shape-related asymmetry (T statistic = 1.281; P = 0.065). Size and shape directional asymmetries are characteristic features of the parental craniofacial skeleton in CL(P). Although directional size asymmetry is present in the parental craniofacial skeleton in CP, shape asymmetry is not a characteristic feature.

Orthodontic scanners: what’s available?

The popularity and availability of virtual technology in orthodontics for the replacement of hard-copy records with electronic records is growing rapidly, with a move towards a ‘digital’ patient for diagnosis, treatment planning, monitoring of treatment progress and outcome. As part of this ongoing development, three-dimensional digital models of the dental arches have the potential to replace traditional plaster models and their associated limitations for treatment planning, appliance construction and simulated treatment outcomes. This article provides the reader with a summary of the currently available benchtop model scanners and intraoral scanners. It is likely that this technology will become increasingly common-place within the orthodontic profession over the next decade.