The use of dental magnification loupes and effect on tooth tissue removal during endodontic access procedure

M.AL Agha, PW Smith, EM FD Jarad.

Aim: To investigate the effect of using dental magnification loupes on the amount of tooth structure removed during endodontic access cavity procedure.

Methodology: Cross over randomized study was conducted at School of Dentistry, University of Liverpool. Ethical approval was sought and granted. Twenty undergraduate dental students, who had not previously used any magnification were recruited. The 20 students were split into two groups. Both groups had an introduction and brief training using presentation including a video showing how to carry out access cavity preparation and the use of magnification loupes prior to conducting the study. The students performed the study under simulated clinical conditions in the operative skills suite. All the teeth were set up in the right quadrant of the phantom head. The first group prepared an endodontic accesses cavities on three 3D printed teeth (1 mandibular 1st molar, 1 maxillary 1st premolars, and 1 maxillary central incisors) utilizing dental loupes at x3.5 magnification. The second group performed an endodontic access on three 3D printed teeth (1 mandibular 1st molar, 1 maxillary 1st premolars, and 1 maxillary central incisors), without using dental loupes. Cone beam Computed tomography (CBCT) was used for scanning the prepared teeth and Mimic software package was used for image analysis.

Results: Mean volume change for maxillary central incisor with loupes was 31.736mm3 (10%) compared with 21.658mm3 (7%) without loupes. The mean volume change for upper maxillary first premolar was 62.214mm3 (21%) with loupes compared with 65.852mm3 (22%) for without loupes. The mean volume change in the lower mandibular molar was 110.155mm3 (23%) with loupes compared with 117.634mm3 (24%) without loupes.

Conclusion: Initial results showed that no major difference in the amount of tooth tissue removed when using dental loups compared with no magnification during endodontic access cavity procedure.

 

Clinicians’ perceptions of class 3 profiles 

Vesey J., Flannigan N., Burnside G., Cooper L., Leung Y.Y. 

Objective: To investigate the impact of patients’ race on clinician’s perception of the need for orthognathic surgery in patients with class 3 profiles.

Design and Setting: Prospective-cross sectional questionnaire distributed to specialist and consultant orthodontists and oral and maxillofacial surgeons in the United Kingdom and Hong Kong.

Materials and Methods: The questionnaire contained composite profile images of Caucasian and Chinese adult male and female individuals manipulated to produce increasingly severe class 3 profiles in both the maxilla and mandible. Respondents were asked whether they felt that ‘a patient presenting with this skeletal pattern would benefit from orthognathic surgery. Multi-level logistic regression analysis was undertaken to investigate the factors influencing decision making.

Results:  The overall response rate was 62% (N=306). All manipulated class 3 profiles had a significant benefit from surgery compared with baseline (p=<0.006, p<0.001).  For equal manipulations, maxillary discrepancies were rated as more likely to benefit from surgery than mandibular. The image’s race and gender, years since becoming a specialist, specialty and the number of orthognathic patients treated per year were highly statistically significant factors for predicting perceived benefit from surgery (p<0.001).  

Conclusions: Oral and maxillofacial surgeons are more likely to perceive benefit from surgery in patients with class 3 profiles than orthodontists. Ethnicity impacts decision making with Chinese profiles more likely to be perceived as having benefit from surgery than Caucasian profiles with the same degree of class 3 discrepancy.

 

Effects of QScan on Plaque and Demineralisation in Orthodontic Patients

Sarkhouh. S. S., Flannigan. N., Burnside. G.Higham. S. M. 

Objective: To test the efficacy of the QScan oral hygiene device used by patients with fixed orthodontics appliances and its effect on plaque accumulation and demineralisation.

Design and Setting: A prospective randomised control trial was undertaken at Liverpool University Dental Hospital.

Materials and methods: Sixty patients with upper and lower fixed orthodontic appliances were recruited and randomly divided into two groups. The intervention group was provided with the QScan device to use as an at home oral hygiene adjunct. The control group were asked to continue with thier oral hygiene care at home without the use of QScan. Both groups were assessed over a period of three orthodontic appointments. At each visit Quantitative Light Fluorescence Induced - Digital (QLF-D) photographs were taken of the dentition in an aim to quantify the amount of plaque and demineralisation.

Results: Fifty-six (93.3%) participants completed the study. There was a total reduction in plaque accumulation in the QScan group, which was statistically significant (p<0.001) when compared to the control group (t-test analysis). Though there was an evident reduction in plaque accumulation, this did not reflect on the levels of demineralisation. Data analysis revealed that the changes in demineralisation between the QScan and control group were insignificant (p>0.05).

Conclusions: The Qscan device has shown to be an effective adjunct for plaque control in orthodontic patients following a longitudinal assessment. However, this reduction did not translate to a significant reduction in demineralisation following an average 15 week assessment.

  

The ‘Culture Button Well’ for 3D cell migration in regenerative endodontics.

N N Longridge, S Albadri, K Hamill, J A Hunt, F Jarad

Introduction

Regenerative Endodontic Procedures (REPs) are endodontic treatment strategies for managing teeth with immature root apices. Despite well reported clinical outcomes for these procedures, the role and influence of tissue scaffolds within this discipline requires greater investigation. Biological hydrogels are frequently used due to their high water content and analogous chemical composition to dental pulp. Variation in the chemical composition of hydrogels, along with tuneable mechanical characteristics and functionalisation can influence the phenotypic differentiation of local progenitor cells. Greater understanding of the interaction between progenitor cells and tissue scaffold is required.

Objectives

Design, develop and validate an in vitro model to enable comparative assessment of biological hydrogels for regenerative endodontic applications.

Methodology

Root canal analogues of varying diameters were designed using Materialise©3matic software and additively manufactured within a surrounding model - the ‘Culture Button Well’ (CBW) - by stereolithography using a Kulzer© caraprint4.0. Medical grade, type-1 bovine collagen was used to produce three-dimensional cylindrical hydrogels within the CBW. pH and UV-crosslinking strategies were utilised to enhance the mechanical properties of the hydrogels. L929 mouse fibroblasts were transfected with green fluorescent protein (GFP) before being seeded onto the upper compartment of the CBW with Dulbecco’s modified eagle media (DMEM). DMEM with 10% FBS was used as chemoattractant within the lower compartment. Hydrogels were imaged by spinning disc confocal scanning laser microscopy (Zeiss spinning disc axio-observer Z1).

Results

GFP-Fibroblasts were imaged on and within the hydrogels following seven days in culture. Hydrogels could be imaged within the CBW without removal or extended processing procedures.

Conclusions

The CBW presents a novel, additively manufactured in vitro model to enable investigation of cell migration in 3D. The CBW can be produced quickly via multiple additive manufacturing techniques. The CBW can be modified to enable hydrogels with different dimensions and characteristics to be comparatively assessed.