Is the Royal London Space Analysis reliable and does it influence orthodontic treatment decisions?

Reliability of mixed dentition space analysis using a digital model obtained from an optical impression: a preliminary study

OBJECTIVE

While mixed dentition space analysis is a common practice in pediatric dentistry, digital models created using an intraoral scanner are not as widely used in clinical settings. This preliminary study used a very small sample size with one reference model and aimed to (1) compare the accuracy of mixed dentition space analysis using a digital model obtained from an optical impression with that of conventional plaster model-based analysis and (2) assess inter-examiner differences.

RESULTS

The space required for the mandibular permanent canine and premolars and arch length discrepancy were calculated using each model. The largest significant difference between plaster- and digital model-based analyses was identified when the right arch length discrepancy was considered (-0.49 mm; 95% confidence interval: -0.95-0.03); however, the value was considered clinically insignificant. Significant inter-examiner differences were observed for six items of the plaster model; however, no such differences were observed when using the digital model. In conclusion, digital model space analysis may have the same level of accuracy as conventional plaster model analysis and likely results in smaller inter-examiner differences than plaster model analysis.

A qualitative evaluation of attitudes toward extractions among primary care orthodontists in Great Britain

INTRODUCTION

The need to extract permanent teeth as part of orthodontic treatment has been keenly debated over many decades. Changes in the frequency of extraction have been well documented; however, we continue to lack an understanding of what influences clinicians' decisions regarding extracting permanent teeth.

METHODS

Purposive sampling was undertaken to obtain representative views from primary care practitioners across Great Britain with a range of experience representing genders and wide geographic distribution. Twenty participants (9 female, 11 male) took part in in-depth, qualitative, 1-to-1 interviews based on a piloted topic guide. Interviews were conducted via video conferencing software with audio recording and verbatim transcription. Thematic analysis was performed with discussion and agreement to identify the main themes.

RESULTS

Five main themes were identified: (1) patient-related factors, such as age and features of the malocclusion, (2) operator factors, including the level of experience, (3) setting, with regard to geographic location and method of remuneration, (4) mechanical approaches, including variations in appliance systems; and (5) self-directed ongoing education, including both formal continuing professional development and informal learning from peers. These factors acted as barriers, enablers, or both in relation to nonextraction treatment.

CONCLUSIONS

Five key influences on extraction decisions among orthodontists in Great Britain were identified. Extraction choices appear to be influenced by various interrelated factors, evolving over time and with increased experience.

A prospective evaluation of the effectiveness of the Royal London Space Planning as a learning tool for space analysis and treatment planning for postgraduate orthodontic students: A quantitative and qualitative study

OBJECTIVE

To assess the effectiveness of the Royal London Space Planning (RLSP) as a learning tool among postgraduate orthodontic students as well as investigate students' attitudes to its use. The RLSP tool is a structured method of orthodontic case assessment and treatment planning.

DESIGN

A prospective cohort study of first year postgraduate orthodontic students who attended teaching of the RLSP.

SETTING

Postgraduate teaching institute.

PARTICIPANTS

First year postgraduate orthodontic students.

METHODS

The outcome measured was the accuracy in assessment and planning of a standardised orthodontic simulated case before and after teaching. Qualitative assessment was conducted through focus group and a semi-structured format after the teaching.

RESULTS

Nineteen students were included in the study. There was an overall improvement in assessment and planning of 20% after the teaching intervention (P < 0.05). Assessment improved by 34% in comparison to treatment planning, which improved by 17% (P < 0.05). The impact of the RLSP was most noticeable on the assessment of crowding in the lower arch which improved by 37% after teaching (P < 0.05). Students felt using the RLSP tool made them more confident and was advantageous to use in training; most felt they would not use the tool after qualification.

CONCLUSION

The RLSP tool is an effective method of teaching assessment and treatment planning to postgraduate orthodontic students. The effect of the RLSP is greater at assessments and less significant for treatment planning. The participant students felt the RLSP improved their confidence in assessment and treatment planning.

Equation for Tooth Size Prediction from Mixed Dentition Analysis for Taiwanese Population: A Pilot Study

Background: In mixed dentition analysis, estimation of the mesiodistal width of unerupted permanent canines and premolars is essential for successful diagnosis and treatment planning. The present study aimed to develop a simple linear equation to predict permanent tooth sizes from mixed dentition analysis for Taiwanese people. Methods: The sample comprised 200 dental casts, derived from Taiwanese patients (100 males and 100 females; age, 12–35 years). Mesial distal tooth widths were measured in dental casts with a digital caliper. A student’s t-test was conducted to detect tooth size correlations with gender-specific differences, as well as intra-arch counterparts. Standard linear regression was conducted to develop a simple equation representing predictions of canine-premolar relationships. Results: All teeth were not significantly different between the left and right sides, regardless of gender and upper or lower arches. In terms of types of teeth, males had larger tooth dimensions in both arches than females. New regression equations for estimating the dimensions of the unerupted canines and premolars in the Taiwanese population were developed. Conclusions: Using a sample of Taiwanese people, new models derived for females and males separately were developed, which should provide highly accurate predictions for unerupted canines and premolars in the Taiwanese population.

Correlation between tooth size-arch length discrepancy and interradicular distances measured on CBCT and panoramic radiograph: an evaluation for miniscrew insertion

INTRODUCTION

The selection of appropriate sites for miniscrew insertion is critical for clinical success.

OBJECTIVES

The aim of the present study was to evaluate how interradicular spaces measured on panoramic radiograph compare with Cone-Beam Computed Tomography (CBCT), and how crowding can influence the presence of available space for miniscrew insertion, in order to define a new "safe zones" map.

METHODS

A total of 80 pre-treatment panoramic radiographs and 80 CBCT scans with corresponding digital models were selected from the archives of the department of Dentistry, Aarhus University. Crowding was measured on digital models, while interradicular spaces mesial to the second molars were measured on panoramic radiographs and CBCTs. For panoramic radiographs, a magnification factor was calculated using tooth widths measured on digital models. Statistical analyses were performed to investigate the correlation between the amount of crowding and the available interradicular space. Visual maps showing the amount of interradicular spaces measured were drawn.

RESULTS

The most convenient interradicular spaces are those between the second molar and the first premolar in the mandible, and between the central incisors in the maxilla. However, some spaces were revealed to be influenced by crowding.

CONCLUSIONS

Calibration of panoramic radiographs is of utmost importance. Generally, panoramic radiographs underestimate the available space. Preliminary assessment of miniscrew insertion feasibility and the related selection of required radiographs can be facilitated using the new "safe zone" maps presented in this article.

Royal London space analysis: plaster versus digital model assessment

Aim

With the advent of digital study models, the importance of being able to evaluate space requirements becomes valuable to treatment planning and the justification for any required extraction pattern. This study was undertaken to compare the validity and reliability of the Royal London space analysis (RLSA) undertaken on plaster as compared with digital models.

Materials and methods

A pilot study (n = 5) was undertaken on plaster and digital models to evaluate the feasibility of digital space planning. This also helped to determine the sample size calculation and as a result, 30 sets of study models with specified inclusion criteria were selected. All five components of the RLSA, namely: crowding; depth of occlusal curve; arch expansion/contraction; incisor antero-posterior advancement and inclination (assessed from the pre-treatment lateral cephalogram) were accounted for in relation to both model types. The plaster models served as the gold standard. Intra-operator measurement error (reliability) was evaluated along with a direct comparison of the measured digital values (validity) with the plaster models.

Results

The measurement error or coefficient of repeatability was comparable for plaster and digital space analyses and ranged from 0.66 to 0.95mm. No difference was found between the space analysis performed in either the upper or lower dental arch. Hence, the null hypothesis was accepted. The digital model measurements were consistently larger, albeit by a relatively small amount, than the plaster models (0.35mm upper arch and 0.32mm lower arch).

Conclusion

No difference was detected in the RLSA when performed using either plaster or digital models. Thus, digital space analysis provides a valid and reproducible alternative method in the new era of digital records.