Prognostic factors, outcomes, and complications for dental autotransplantation: an umbrella review.

BACKGROUND: Dental autotransplantation (DAT) is a biological way of replacing missing or compromised teeth for patients. The techniques often necessitate a multi-disciplinary approach. The prognosis and success of the procedure may be impacted by variable factors in varying degrees. OBJECTIVE: Evaluating outcomes and complications of DAT, including prognostic factors using an umbrella review. SEARCH METHODS: Six databases were searched for all relevant systematic reviews published up to 30 June 2022. No restrictions were applied to language or publication date. SELECTION CRITERIA: Systematic reviews and meta-analyses of DAT studies. DATA COLLECTION AND ANALYSIS: Identification, screening, eligibility, and quality assessment using the AMSTAR 2 tool were performed independently by two authors (M.C. and S.A.). Two studies (20%) scored moderate, six studies (60%) scored low, and two studies (20%) scored critically low. Data were analysed using a random effects meta-analysis, and meta-regression was performed to investigate the effect of open and closed apices on the dependent variables. The results were summarised as relative risk ratios. RESULTS: A total of 310 studies were eligible for inclusion, of which 20 studies were selected for full-text evaluation. Ten systematic reviews were included, 9 of which had a meta-analysis. Overall findings suggest that DAT offers favourable success and survival rates. Meta-regression results indicate that a closed apex increased the proportion of ankylosis and resorption, reduced survival but had no effect on success during the observational period. LIMITATIONS: A varying degree of heterogeneity and bias was present in all systematic reviews. The samples of donor teeth included in the systematic reviews also varied morphologically. CONCLUSIONS: DAT is a technique-sensitive procedure requiring a multidisciplinary team, vigilant case assessment and thorough consideration of the respective prognostic factors involved. Despite methodological limitations reported across studies, DAT shows favourable success and survival rates, with a distinctive advantage of bone induction and soft tissue thickness preservation, and should, therefore, be considered as a viable treatment modality. Standardisation of clinical guidelines and practice are highly recommended. REGISTRATION: CRD42020202484.

Aligning orthodontic education: Investigating the use of a digital app to improve the performance in managing orthodontic problems.

INTRODUCTION: General dentists are qualified to manage orthodontic emergencies within their scope of practice. This may involve advice, hands-on intervention or referral to a specialist orthodontist. This study aimed to assess the effect of an orthodontic app on dental undergraduates' ability to manage common orthodontic issues. In addition, this study aimed to determine the confidence of dental students in finding information related to orthodontic emergencies (CFI) as well as their confidence in managing orthodontic emergencies (CMOE). MATERIALS AND METHODS: Students were randomised into one-of-three groups, an app group, an internet group and a closed-book, exam-style group. All participants self-reported their CFI and CMOE. Following this, all participants were asked to complete a multiple-choice question (MCQ) paper based on clinical orthodontic scenarios. In addition, the app group were instructed to complete an app usability questionnaire (MAUQ). RESULTS: Approximately, 91.40% of students (n = 84) had not received clinical training in managing orthodontic emergencies, and 97.85% (n = 91) had not managed an orthodontic emergency clinically within the last 6 months of their training. The mean score for CFI was 0.10 out of 1.0 (SD 0.11) and CMOE was 0.28 out of 1.0 (SD 0.23). Statistically significant better MCQ scores were found in the app group, and no statistically significant difference was found between the internet and exam-style group. CONCLUSIONS: This study is the first to consider the use of an orthodontic app to aid in the management of orthodontic issues. It has practical implications for how mobile apps can aid in learning and can be incorporated into the wider dental field.

Cost-effectiveness of orthodontics: a systematic review.

BACKGROUND: Health economic evaluation is a methodology to maximize health benefits and minimize opportunity costs and is of increasing importance in informing resource allocation decisions in healthcare. OBJECTIVE: This systematic review aims to assess the availability and quality of economic evaluations of any orthodontic interventions and summarize the conclusions of these studies. SEARCH METHODS: A thorough search of the literature was carried out including terms related to orthodontic interventions and economic evaluation between January 2000 and February 2022. MEDLINE, EMBASE, SCOPUS, Web of Science, NHS Economic Evaluation Database, and Cochrane were searched. Grey literature was searched and further hand-searching was performed on the reference lists of relevant systematic reviews. SELECTION CRITERIA: Studies on cleft lip and palate surgery and sleep apnoea were excluded due to the multi-disciplinary nature of these conditions which might alter the applicability of the result to orthodontic interventions. Two independent reviewers selected studies for inclusion. DATA COLLECTION AND ANALYSIS: Data extraction was carried out through full text analysis of included studies by two authors. The quality of each study was assessed according to the Drummond 10-point Checklist and the National Institute for Health and Care Excellence (NICE) Quality Appraisal Checklist for Economic Evaluations. Characteristics and conclusions of included articles were descriptively summarized. RESULTS: Sixteen articles met inclusion criteria. Most of the included articles were trial-based studies, with only one model-based study. Orthodontic interventions assessed included crossbite correction, functional appliance treatment and orthognathic surgery. Most studies were carried out in Europe and specifically in Sweden. The quality of included studies was generally low with 69% of studies reported as having serious limitations according to the NICE Checklist. CONCLUSION: This review highlighted a lack of economic evaluations for orthodontic interventions, and limitations of existing economic evaluations. Recommendations on future research are provided. REGISTRATION: The protocol for the systematic review was registered on the NIHR Database (www.crd.york.ac.uk/prospero, CRD42021220419).

Quality-of-life improvement, psychosocial benefits, and patient satisfaction of patients undergoing orthognathic surgery: a summary of systematic reviews.

BACKGROUND: Function, aesthetics, and social and psychological well-being are all important aspects for patients undergoing orthognathic surgery. OBJECTIVE: To evaluate the impact of orthognathic surgery on patient perception and quality of life before, during and after treatment. SEARCH METHODS: All relevant systematic reviews published up to 31st July 2020 have been searched via MEDLINE via OVID, Scopus, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, PsycINFO, AMED (Allied and Complementary Medicine Database), and PubMed.Ongoing systematic reviews and grey literature were eliminated. A manual search was also undertaken, and no restrictions were applied to language or publication date. SELECTION CRITERIA: Systematic reviews involving dentofacial deformities related to systemic disorders, cleft lip and palate, facial trauma, and syndromes affecting cranial and dentofacial structures were excluded. DATA COLLECTION AND ANALYSIS: Identification, screening, eligibility, and quality assessment [using the AMSTAR 2 tool (A Measurement Tool to Assess Systematic Reviews)] were performed by two authors independently. Data were synthesized qualitatively using thematic analysis. RESULTS: A total of 662 eligible studies were obtained of which 24 studies were selected for full-text evaluation, resulting in 12 eligible systematic reviews. LIMITATIONS: Due to heterogeneity of data, quantitative analysis was not possible. CONCLUSIONS AND IMPLICATIONS: Aesthetics and function are the main motives for seeking orthognathic surgery. Patient assessment before, during, and after orthognathic surgery is necessary for a thorough evaluation of self-perception and satisfaction throughout treatment. While psychological and social domains improved after orthognathic surgery treatment, the quality of life can deteriorate transiently during the pre-surgical orthodontic phase of treatment. A standardized assessment tool needs to be developed to assess quality-of-life changes consistently and provide comparable results. REGISTRATION: CRD42020199091.

Comparison of automated digital Peer Assessment Rating compared with measurements performed by orthodontists, dental students, and assistants using plaster, additive manufactured, and digital models.

BACKGROUND: There are little scientific data on fully automated Peer Assessment Rating (PAR); this study compares a number of PAR scoring methods to assess their reliability. OBJECTIVES: This investigation evaluated PAR scores of plaster, 3D printed, and virtual digital models scored by specialist orthodontists, dental auxiliaries, undergraduate dental students,and using a fully automated method. MATERIALS AND METHODS: Twelve calibrated assessors determined the PAR score of a typodont and this score was used as the gold standard. Measurements derived from a plaster model, a 3D printed model, and a digital model, were compared. A total of 120 practitioners (specialist orthodontists, dental auxiliaries, and undergraduate dental students, n = 40 each) scored the models (n = 10) per group. The digital models were scored twice, using OnyxCeph (OnyxCeph) and OrthoAnalyzer (3Shape). The fully automated PAR scoring was performed with Model+ (Carestream Dental). RESULTS: Neither type of model (P = 0.077), practitioner category (P = 0.332), nor interaction between the two (P = 0.728) showed a statistically significant effect on PAR scoring. The mean PAR score and standard deviation were comparable for all models and groups except the automated group, where the standard deviation was the smallest (SD = 0). Overall, the greatest variation was observed for weighted overjet and contact point displacements. CONCLUSIONS: PAR scoring using plaster, 3D printed, and digital study models by orthodontists, dental auxiliaries, dental students, and a fully automated method produced very similar results and can hence be considered equivalent. Automated measurements improve repeatability compared with all groups of practitioners, but this did not reach the significance level.

Clinical communication in orthodontics: Any questions?

OBJECTIVE: To measure patient-perceived standards of clinician communication and identify elements of deficient performance. Good communication can improve the quality of care, patient satisfaction and compliance with treatment. DESIGN: Cross-sectional questionnaire service evaluation. SETTING: Two university dental hospital orthodontic departments. PARTICIPANTS: Any patients aged 10 years and over attending the orthodontic department for treatment or consultation were eligible for inclusion. Patients who required third-party translation services were excluded. METHODS: Clinicians provided the modified 15-item Communication Assessment Tool (CAT) to up to five patients in a clinical session. A front sheet for clinician characteristics was used and anonymised with a unique identifier. Univariable logistic GEE models examined associations among responses and clinician characteristics. RESULTS: There were 55 clinicians with 204 patient responses. The overall percentage of '5=excellent' ratings was 88% (SD 0.16). The lowest scoring item was 'encouraged me to ask questions' (55.8%). Based on clinician characteristics, there were lower odds of an excellent response for certain CAT items. There were higher odds of an excellent response if English was not the clinician's first language (1.05; 95% confidence interval = 1.00-1.09; P=0.03). CONCLUSION: There is a high standard of patient-clinician communication in the hospital orthodontic setting. Key areas of communication that require attention include encouraging patients to ask questions, talking in terms they can understand, recognising their main concerns and involving them in the decision-making process. The results of this study can be used to inform communication skills training and be replicated in similar dental settings (primary and secondary care) as part of quality improvement.

Adherence to RCS recommendations for extraction of first permanent molars in a teaching hospital: To compensate or not to compensate?

OBJECTIVE: To observe whether paediatric dentists and orthodontists balance and compensate the extraction of first permanent molars (FPMs) in children aged 7-11 years. DESIGN: Service evaluation. SETTING: UK dental teaching hospital. METHODS: Retrospective analysis of FPM extraction patterns in patients aged 7-11 years that attended for extraction of FPMs from 1 January 2019 to 31 January 2020 (13-month period). RESULTS: A total of 194 patients were included and they collectively had 435 FPMs extracted. No balancing extractions to prevent dental centreline shifts and no lower FPM compensatory extractions were performed. Compensatory extraction of good prognosis upper FPMs were performed in 64% (94/146) of cases to avoid overeruption. Orthodontic input was sought for poor prognosis lower FPMs in 76% of cases compared to 51% for poor prognosis upper FPMs. CONCLUSION: Compensatory extraction of good prognosis upper FPMs to avoid overeruption appears to be a common practice at Guy's and St Thomas' Hospitals. There was also higher demand for orthodontic advice for cases presenting with poor prognosis lower FPMs compared to poor prognosis upper FPMs, which suggests that paediatric dentists may prefer for the final decision on upper FPM compensatory extractions to be made by an orthodontist, even with national guidelines available. More high-quality research on the topic is required to determine the necessity of this practice for achieving optimal long-term oral health in children.

Survival probability of dental autotransplantation of 366 teeth over 34 years within a hospital setting in the United Kingdom.

INTRODUCTION: The purpose of this retrospective study was to evaluate 34 years' experience of autotransplantation of teeth during orthodontic treatment. METHODOLOGY: Treatment was completed at Queen Mary's Hospital, Sidcup, Kent, UK, during the period 1969-2003. A total of 366 teeth were transplanted in 314 patients. RESULTS: Canines totalled 78 per cent of all autotransplanted teeth; mean age of patient was 19.4 years. Survival probability for the first 5 years post-autotransplantation was 95 per cent, 94 per cent for the subsequent 5 years, and 88 per cent after 15 years. The maximum observation period was 34 years, the median was 2.0 years, and the mean was 3.51 (standard deviation = 3.68) years. Of the observed teeth, 10 failed and these were lost due to unsuccessful periodontal ligament regeneration and persistent mobility grade III (or greater). Apical pathology was observed in 16 per cent of all autotransplanted teeth. In 79 per cent of this subgroup, apical pathology was evident in the first 3 years post-operatively. Seventy per cent of all external resorption also occurred within the first 3 years. Internal resorption was rare but its occurrence was mostly observed between the second and sixth year post-transplantation. A minority of autotransplanted teeth [14 per cent (n = 51)] needed root canal therapy, and this was completed within the first 6 months post-transplantation. CONCLUSIONS: Autotransplantation can be a justified procedure with good survival probability. It can be considered an alternative to other treatments, such as prosthodontic replacement of teeth.

Association between severity of hypodontia and cephalometric skeletal patterns: a retrospective study.

Objective: To assess if severity of hypodontia is related to a specific skeletal pattern. Study design: Lateral cephalometric radiographs and dental panoramic tomographs of 182 hypodontia patients were analysed. The severity of hypodontia was recorded and the sample was divided into groups with mild (n = 71), moderate (n = 56) and severe (n = 55) hypodontia. According to ethnicity, the sample was further subdivided into White Caucasians, African-British, and Arabian/Indian subgroups. Cephalometric measurements were used to quantify the skeletal discrepancy and vertical facial dimensions. Mean and standard deviation for each group were obtained for comparison and an analysis of variance (ANOVA) was carried out to assess the level of significance between the means of the readings in different severity groups. Results: In the white Caucasian group, increased severity of hypodontia, was related to a retrusive maxilla with concomitant reduction of A point, Nasion, B point (ANB), reduced mandibular plane angle and anterior lower facial height (P value: 0.0935-0.9371). For the Black-British and Arabian/Indian groups' findings were inconsistent, with no specific pattern as the number of missing teeth increased. Conclusion: The white Caucasian group followed a pattern that has previously been reported in other studies. For Black-British and Arabian/Indian groups' findings were inconsistent and no specific pattern emerged for different degrees of hypodontia.

Anatomic landmarks and availability of bone for placement of orthodontic mini-implants for normal and short maxillary body lengths.

INTRODUCTION: Increasing numbers of orthodontic mini-implants are placed in the anterior maxilla. To our knowledge, bone levels and root proximity of patients with cephalometrically short maxillae have not been investigated before. The first, second, and third rugae were used as clinical reference lines, and the aim of this study was to measure bone availability in that area by comparing patients with short and normal maxillary body lengths. METHODS: The sample consisted of 21 patients in each group: short maxillary body length and normal maxillary body length. The patients' study models were bisected, and the outline of the palatal contour was marked on the surface. The models were scanned, and the palatal contours were superimposed on the palatal structures of their respective initial cephalometric headfilms, and the vertical and oblique bone levels of the sagittal plane were compared using the Student t test. The level of significance was set at P <0.05. RESULTS: Compared with maxillae of normal maxillary body length, less bone was available in maxillae of short maxillary body length. However, the differences did not reach clinical or statistical significance (P >0.05) at the third rugae. CONCLUSIONS: Almost equivalent average bone depth at the third rugae in patients with normal and short maxillary body lengths suggests that this site can be used for 8-mm long obliquely inserted orthodontic mini-implants.

Alignment efficiency and esthetic performance of 4 coated nickel-titanium archwires in orthodontic patients over 8 weeks: A multicenter randomized clinical trial.

INTRODUCTION: The objective of this 4-arm parallel study was to evaluate the alignment efficiency and esthetic performance of 4 coated nickel-titanium archwires over an 8-week period. METHODS: Patients in the permanent dentition requiring maxillary and mandibular fixed orthodontic treatment with a preadjusted edgewise appliance were eligible for inclusion. Patients attending 4 hospital departments (United Kingdom and Italy) were randomly allocated to 1 of 4 treatment interventions: (1) BioCosmetic (Forestadent, Pforzheim, Germany), 0.017 in; (2) Titanol (Forestadent), 0.016 in; (3) TP Aesthetic (TP Orthodontics, La Porte, Ind), 0.014 in; and (4) Tooth Tone (Ortho Organizers, Calsbad, Calif) 0.016 in. Block randomization with block sizes of 4 and 8 was used to ensure an allocation ratio of 1:1:1:1. The primary outcome was alignment efficiency determined by the reduction in Little's irregularity index (mm). Secondary outcomes were color change using the Commission Internationale de L'Eclairage L*a*b* system and percentage of coating loss. Blinding was only applicable to outcome assessment of alignment efficiency. Regression models with Sidak's multiple comparison of means were used to analyze the data. RESULTS: One hundred fifty patients (300 dental arches) were allocated to the treatment interventions, including 61 male and 89 female subjects with a mean age of 16.60 years. The average duration of follow-up was 63.65 days. Baseline characteristics for the archwire groups were similar. One patient was lost to follow-up. Five percent (n = 15) of the archwires fractured: BioCosmetic, 5.3% (n = 4); Titanol, 6.8% (n = 5); TP Aesthetic, 5.3% (n = 4); and Tooth Tone, 2.7% (n = 2). We analyzed 283 dental arches for alignment efficiency. There was no statistically significant difference for mean reduction in irregularity between the archwire groups (P = 0.627): BioCosmetic (n = 71), 3.86 mm (95% CI, 3.31-4.41); Titanol (n = 69), 4.51 mm (95% CI, 4.00-5.02); TP Aesthetic (n = 71), 4.13 mm (95% CI, 3.49-4.78); and Tooth Tone (n = 72), 4.21 mm (95% CI, 3.89-4.46). There was a statistically significant difference between archwire groups for color change (P = 0.001) and percentage of coating loss (P = 0.001), with BioCosmetic performing best in both parameters. CONCLUSIONS: There was no difference between the archwires for alignment efficiency. BioCosmetic performed statistically significantly better than did the other groups for both color change and coating loss. REGISTRATION: This trial was registered with the East Midlands NHS Research Ethics Committee (12/EM/0190). PROTOCOL: The protocol was not published before trial commencement.

Precision of Le Fort I osteotomy: planning versus outcome. A multi-centre retrospective study.

INTRODUCTION: The purpose of this study was to evaluate the accuracy of Le Fort I surgery by comparing planned surgical movements with actual outcomes. MATERIALS AND METHODS: A minimum number of seven consecutive cases that had undergone a Le Fort I osteotomy procedure alone or in combination with a mandibular osteotomy from six different hospital units in the East of England between 2009 and 2010 were identified. A total of 56 cases met the inclusion criteria where surgical splints were used and model surgery had been performed. Pre- and post-operative lateral cephalograms were digitised using Dolphin© imaging software (Version 10.0) and three cephalometric points were assessed to measure precision of surgical movements: A point (A-pt); Upper incisor tip (U1 tip); and Upper first molar occlusal point (U6 occ). The final position of the maxilla was compared to the planned position. RESULTS: In 71% of cases surgical movements were within 2 mm and 20% of this group were within 1 mm of the predicted position. The mean accuracy was 1.39 mm (SD 0.92 mm) for the former and 0.78 mm (SD 0.58 mm) for the latter. Accuracy correlated negatively with increased surgical complexity, particularly posterior differential impactions of the maxilla. There was no statistically significant difference between centres. CONCLUSIONS: Pre-operative surgical planning of Le Fort I osteotomies was generally accurate. This study demonstrates that different operators across six centres produced consistent surgical outcomes and this confirms previously reported data.

Bond strength of stainless steel orthodontic brackets bonded to prefabricated acrylic teeth.

OBJECTIVES: The purpose of this in-vitro study was to evaluate the force to debond stainless steel orthodontic brackets bonded to acrylic teeth using different combinations of adhesive and surface treatments. MATERIALS AND METHODS: One hundred prefabricated upper lateral incisor acrylic teeth were divided into 4 equal groups: Transbond XT® adhesive only (Group 1, control), Transbond XT® adhesive with sandblasting (Group 2), Transbond XT® adhesive with abrasion / + methyl methacrylate (MMA) (Group 3) and Triad® Gel only (Group 4). The force in Newtons (N) to debond the brackets was measured. One-way analysis of variance (ANOVA) and pairwise multi-comparison of means (Sidak's adjustment) were undertaken. RESULTS: The highest force to debond was recorded for Group 2 (275.7 N; SD 89.0) followed by Group 3 (241.9 N; SD 76.0), Group 1 (142.7 N; SD 36.7) and Group 4 (67.9 N; SD 21.1). Significant differences in bond strength measurements between the experimental groups were detected. Mean force values for the groups revealed no significant differences between Group 2 and Group 3 (p>0.05). CONCLUSIONS: Both sandblasting and surface abrasion/+ application of methyl methacrylate (MMA) in combination with Transbond XT® adhesive are recommended for bonding stainless orthodontic brackets to acrylic teeth.

Assessing lower incisor inclination change: a comparison of four cephalometric methods.

OBJECTIVE: Cephalometric inclination change of the lower incisors during orthodontics is used to assess treatment outcome. The lower border of the mandible is commonly used for measuring inclination change, despite it being subject to remodelling in growing patients. Superimposition of radiographs using Björk's 'stable structures' is intended to exclude these growth changes. We tested whether there is a significant difference for three commonly used methods to assess inclination change induced by orthodontic treatment (Me-Go, Go-Gn, the tangent to the lower border of the mandible) when comparing it to Björk's 'stable structures'. METHODS: Björk's superimposition does not allow measuring incisor inclination changes directly; hence, one pre- and mid-treatment cephalogram of 39 growing orthodontic patients were superimposed in this retrospective study. The radiographs were taken at least 1 year apart (120 weeks; SD = 34.4). Patients undergoing growth modification treatment were excluded. Standardized cephalograms were hand traced and changes in lower incisor inclination, using the three mandibular planes, were compared to the changes obtained by anatomical superimposition of Björk's 'stable structures'. RESULTS: Linear regression showed good intra-class correlation (ICC) between all methods. ICC was 0.96 for Me-Go, 0.94 for Go-Gn, and 0.92 for the lower border tangent. ICC for operator reliability was 0.99. LIMITATIONS: Measurement errors affect all investigations of both analogue and digital radiographs, but movement artefacts particularly apply to the latter. Cephalometry uses two-dimensional measurements of a three-dimensional subject, which can lead to further inaccuracies. These limitations have to be taken into account when interpreting the results of our investigation. CONCLUSION: Data obtained from Björk's superimposition did not vary significantly from the other more commonly used techniques (Me-Go, Go-Gn, and the tangent to the lower border of the mandible). Remodelling of the lower border of the mandible was insignificant for the time period investigated.

In vitro comparison of contemporary radiographic imaging techniques for the measurement of inter-radicular width.

OBJECTIVE: To assess the reliability of inter-radicular measurements taken using dental pantomograms (DPT), long cone periapical radiographs (LCPA) and cone bean computed tomography (CBCT). MATERIALS/METHODS: A typodont simulating a hypodontia patient undergoing fixed appliance treatment was used. LCPAs, DPT, I-CAT and Accuitomo CBCT images were taken and the distances between the edentulous spans were measured at the midpoint of the roots and the cemento-enamel junctions (CEJ) of adjacent teeth. The results of each modality were compared to each other to the actual inter-radicular space. RESULTS: The DPT overestimated inter-radicular widths by 2 mm or more [mean: 2.48; 95% confidence interval (CI): -1.09 to 6.05 mm]. The LCPA overestimated the inter-radicular widths by 1.5 mm with a 95% CI of -0.095 to 4.03 mm. The mean differences between gold standard (model) and Accuitomo was 0.57 mm (95% CI: -0.37 to 1.51 mm) for the root mean and 0.22 mm (95% CI: -0.52 to 0.96 mm) for the CEJ. This was similar to the differences between the model and I-CAT where the inter-radicular root mean difference was 0.38 mm (95% CI: -0.38 to 1.14 mm) and the CEJ mean difference was 0.21 mm (95% CI: -0.50 to 0.92 mm). CONCLUSION: The CBCT overestimated the root distance by 0.48 mm and the CEJ width by 0.22 mm, which is clinically irrelevant for implant placement. The DPT overestimated inter-radicular width by 2 mm and the LCPA by 1.5 mm and this difference may put roots of adjacent teeth at risk during implant placement.

Comparison of validity, repeatability and reproducibility of the Peer Assessment Rating (PAR) between digital and conventional study models.

INTRODUCTION: The validity, reliability and inter-method agreement of Peer Assessment Scores (PAR) from acrylic models and their digital analogues were assessed. METHOD: Ten models of different occlusions were digitised, using a 3 Shape R700 laser scanner (Copenhagen, Denmark). Each set of models was conventionally and digitally PAR-scored twice in random order by 10 examiners. The minimum time between repeat measurements was two weeks. The repeatability was assessed by applying Carstensen's analysis. Inter-method agreement (IEMA) was assessed by Carstensen's limit of agreement (LOA). RESULTS: Intra-examiner repeatability (IER) for the unweighted and weighted data was slightly better for the conventional rather than the digital models. There was a slightly higher negative bias of -1 .62 for the weighted PAR data for the digital models. IEMA for the overall weighted data ranged from -8.70 - 5.45 (95% Confidence Interval, CI). Intra-class Correlation Coefficients lICC) for the weighted data for conventional, individual and average scenarios were 0.955 0.906 - 0.986 CI), 0.998 (0.995 - 0.999 CII. ICC for the weighted digital data, individual and average scenarios were 0.99 (0.97 - 1.00) and 1.00. The percentage reduction required to achieve an optimal occlusion increased by 0.4% for the digital scoring of the weighted data. CONCLUSION: Digital PAR scores obtained from scanned plastic models were valid and reliable and, in this context, the digital semi-automated method can be used interchangeably with the conventional method of PAR scoring.

A comparison of roughness parameters and friction coefficients of aesthetic archwires.

AIM: Compare surface roughness of 'aesthetic' nickel-titanium (NiTi) archwires with their dynamic frictional properties. METHODS: Archwires investigated were: four fully coated tooth coloured [Forestadent: Biocosmetic (FB) and Titanol Cosmetic (FT); TOC Tooth Tone (TT); and Hawley Russell Coated Superelastic NiTi (HRC)]; two partially coated tooth coloured [DB Euroline Microcoated (DB) and TP Aesthetic NiTi (TP)]; two rhodium coated [TOC Sentalloy (TS) and Hawley Russell Rhodium Coated Superelastic NiTi (HRR)]; and two controls: stainless steel [Forestadent Steel (FS)] and NiTi archwire [Forestadent Titanol Superelastic (FN)]. Surface roughness [profilometry (Rugosurf)] was compared with frictional coefficients for archwire/bracket/ligature combinations (n = 10). Analysis of variance, Sidak's multiple comparison of means, and Spearman's correlation coefficient were used for analysis. RESULTS: Roughness coefficients were from low to high: FB; FN; TT; FS; TS; HRR; FT; DB; TP; HRC. Friction coefficients were from low to high: TP; FS; FN; HRR; FT; DB; FB; HRC; TS; TT. Coated archwires generally exhibited higher friction than uncoated controls. TP had the lowest friction but this was not statistically significant (P < 0.05). Friction of tooth coloured coated archwires were significantly different for some wires. Spearman's correlation did not demonstrate consistency between surface roughness (R a) and dynamic friction. CONCLUSIONS: Aesthetic archwires investigated had either low surface roughness or low frictional resistance but not both properties simultaneously. Causes for friction are likely to be multifactorial and do not appear to be solely determined by surface roughness (measured by profilometry). For selecting the most appropriate aligning archwire, both surface roughness and frictional resistance need to be considered.

The most distal palatal ruga for placement of orthodontic mini-implants.

OBJECTIVE: To evaluate the stability and bone availability of the most distal (third) palatal ruga, as an anatomical region for safe insertion of orthodontic mini-implants (OMIs) in the anterior palate. STUDY DESIGN: Orthodontic records of 35 patients were analysed. Initial (T1) and final (T2) study models were bisected and the outline of the palatal contour was marked on the surface. Models were scanned and the palatal contours were superimposed on the palatal structures on the respective initial and final cephalometric images. Cephalometric measurements were used to assess vertical (3rdRug-PP, 2ndRug-PP, and 1stRug-PP), and oblique bone levels (3rdRug-U1, 2ndRug-U1, 1stRug-U1, and 3rdRug-U1(o)). Paired Student's t-test was used to compare measurements between T1 and T2. RESULTS: The position of the third palatal ruga remained stable during orthodontic treatment (Δ2ndRug-3rdRug P = 0.1mm; P = 0.61 and Δ1stRug-3rdRug P = 0.2mm; P = 0.39). Bone availability also remained adequate (3rdRug-U1T2 (o) = 9.9mm). CONCLUSION: The third palatal ruga is a reliable clinical landmark to evaluate bone availability for the placement of OMIs in the anterior palate.

Three dimensional anatomical exploration of the anterior hard palate at the level of the third ruga for the placement of mini-implants--a cone-beam CT study.

AIM: The aim of this retrospective investigation was to measure vertical bone thickness on the hard palate, determine areas with adequate bone for the insertion of orthodontic mini-implants (MIs), and provide clinical guidelines for identification of those areas. MATERIALS AND METHODS: Pre-treatment records of 1007 patients were reviewed by a single examiner. A total of 125 records fulfilled the inclusion criteria and were further investigated. Bone measurements were performed on cone-beam computed tomography scans, at a 90° angle to the bone surface, on 28 predetermined and standardized points on the hard palate. Bone thickness at various areas was associated to clinically identifiable areas on the hard palate by means of pre-treatment plaster models. RESULTS: Bone thickness ranged between 1.51 and 13.86 mm (total thickness) and 0.33 and 1.65 mm (cortical bone thickness), respectively. Bone thickness was highest in the anterior palate and decreased significantly towards more posterior areas. Plaster model analysis revealed that bone thickness was highest at the level of the third palatal ruga. CONCLUSIONS: The areas on the anterior palate with adequate bone thickness for successful insertion of orthodontic MI correspond to the region of the third palatal ruga. These results provide stable and clinically identifiable landmarks for the insertion of palatal MIs.