Correlation Between Colour and Hypersensitivity of First Permanent Molars With Molar Incisor Hypomineralisation (MIH)

Overview

Cheese molars (MIH: molar incisor hypomineralisation) can be recognized not only by their colour abnormalities but also by their hypersensitivity. Clinical management of these teeth may become challenging by the chronic hypersensitivity, which makes various steps of a treatment, such as pain control or light curing of any type of composite restorations, difficult or even impossible, despite profound local anesthesia. Hypersensitivity can be detected by the clinician based on the patient's statements or reaction. On the other hand, colours and structural abnormalities can be easily assessed by visual inspection. The aim of this study is to determine the relationship between hypersensitivity and the colour of the enamel defect on young first permanent molars. A correlation between colour of the defect and hypersensitivity could enable early prognosis leading to preventive measures in order to delay, amplify or even avoid the onset of the symptoms. Children diagnosed with MIH on their first permanent molars of different severity are matched to children with sound molars. They are identified by the annual school dental check-up and are invited to take part in the study. The children will be invited to the university dental clinic via letter for the first appointment. Upon parental consent, the teeth will be photographed and scanned as well as investigated for hypersensitivity through a gentle air blast.

Aim of the study is the correlation between the colour of the enamel defect and hypersensitivity in young first permanent molars. Children diagnosed with MIH from the onset of eruption of the first permanent molar, matched by age with children with sound first permanent molars are investigated. Children screened by the school dental services of Basel-Stadt as well children attending the department of children and adolescents (KJZM) of the University Centre for Dental Medicine in Basel (UZB), diagnosed with MIH on one or more first permanent molars receive a letter of information- invitation to be seen in the department of children and adolescents (KJZM). The control group consists of fit and healthy children 5-8 years old, who attend the department of children and adolescents (KJZM-UZB) for their regular dental check-ups. A written informed consent will be obtained from the parents/legal guardians. Colour definition The exact colour determination of the teeth will be carried out as follows: The teeth are photographed with a canon SLR camera. (Canon EOS 80D; Canon inc. Japan), a ringflash (Macro Ring Lite MR-14EXII; Canon) and a macro lens (EF-S 60mm 1:2:8 USM; Canon) will be used. All camera settings (1/250, aperture F20, iso-sensitivity 100 and a fixed white balance AWBW (white priority), flash intensity +/-0) and the tooth-lens distances (25 cm) are standardized by one operator (VM, SR). A colour reference card (grey card) is photographed together with the tooth of interest in order to identify and equalize the colour deviations. The resulting photo will be uploaded to the Photoshop Adobe 6 and the values of the RGB code (0-255 for each of the three colours) will be determined. The tolerance range is set to +/- 10. If the 3 colours are within the tolerance, the photo can be used to determine the colour of the tooth to be examined. The darkest part of the tooth is then determined. The degree of darkness is indicated by a number between zero and one hundred, where L=100 is white and L=0 is black (Wiedrichs et al. 2023). The sensitivity of the teeth will be assessed by using the Schiff Cold air Sensitivity Scale (Schiff et al 1994). Teeth will be dried by an air blast defined at 5 bar. Prior to the examination patient will be introduced to the procedure by "tell-show-do" method. Based on the patient's reaction, the sensitivity to the air shock is divided into: 0 no reaction to the stimulus 1. reaction, but continuing with the stimulus possible 2. reaction, moving, demanding termination 3. painful, immediate abandonment of procedure In addition to the sensitivity, assessed by the main investigator (VM or SR), the Wong-Baker Faces Pain Rating Scale (Wong-Baker FACES Foundation 2022) will be applied. The scale consists of six faces representing different expressions of pain, ranging from a laughing face with no pain (score 0) to a crying face with severe pain (score 10). Each face has a numerical score from 0 to 10 indicating pain intensity. Children will be asked to select the face that best describes their current pain experience. Each appointment lasts a maximum of 30 minutes. In addition to the Schiff-Cold-Air-Scale-Test, hypersensitivity is also determined using the Face-Pain-Scale.