Horatio M. Pollock,Ph.D.

Psychiatric Quarterly -     

Outcomes of oral squamous cell carcinoma arising from oral epithelial dysplasia: rationale for monitoring premalignant oral lesions in a multidisciplinary clinic

Surveillance of oral epithelial dysplasia results in a number of newly diagnosed cases of oral squamous cell carcinoma (SCC). The clinical stage of oral SCC at diagnosis influences the magnitude of treatment required and the prognosis. We aimed to document the stage, treatment, and outcome of oral SCC that arose in patients who were being monitored for oral epithelial dysplasia in a dedicated multidisciplinary clinic. Those with histologically diagnosed lesions were enrolled on an ethically approved protocol and molecular biomarker study. Details of clinical and pathological TNM, operation, radiotherapy, recurrence, second primary tumour, and prognosis, were recorded in patients whose lesions underwent malignant transformation. Of the 91 patients reviewed (median follow-up 48 months, IQR 18-96), 23 (25%) had malignant transformation. All were presented to the multidisciplinary team with stage 1 disease (cT1N0M0). Of these, 21 were initially treated by wide local excision, 2 required resection of tumour and reconstruction, and 2 required adjuvant radiotherapy. At follow-up 3 had local recurrence, one had regional recurrence, one had metachronous lung cancer, and 5 had second primary oral SCC. There were further diagnoses of oral dysplasia in 5 during follow-up, and it is estimated that 76% of patients will have one or other event in 5 years. Disease-specific survival was 100% and overall survival was 96% (22/23). Median follow-up after diagnosis of oral SCC was 24 months (IQR 11-58). Specialist monitoring of oral epithelial dysplasia by a multidisciplinary team allows oral SCC to be detected at an early stage, and enables largely curative treatment with simple and usually minor surgical intervention. The high incidence of second primary oral SCC in high-risk patients with oral epithelial dysplasia further supports intensive targeted surveillance in this group.     

Using bearing area parameters to quantify early erosive tooth surface changes in enamel: A pilot study

Objectives

Most in vitro studies investigate the erosive process using relatively simple roughness parameters such as roughness average (R_a). In isolation, R_a may misrepresent the surface features. Further, few studies report baseline surface characteristics after sample preparation. This study aimed to test the hypothesis that measuring the bearing area parameters in addition to R_a may be useful when qualifying the surface of enamel at baseline and after an erosive challenge. The null hypothesis for this study was that the bearing area parameters provide no more useful information than R_a alone, when qualifying the surface of enamel at baseline and after an erosive challenge.

Methods

Enamel slabs (n = 20) were prepared from human (n = 2) and bovine (n = 4) incisor teeth and polished with 0.05 μm paste. Roughness average (R_a) and bearing parameters (MR1, MR2, R_pk, R_k, R_vk) were used to record baseline characteristics. Specimens were subjected to erosion with 1% citric acid solution for 1 min. Profilometric characteristics were recorded post-erosion, along with the maximum height changes within the profile. T-tests were carried out in order to compare baseline surface characteristics between tissue types. Post-erosion, analysis of variance (ANOVA) was used to test the effects of tissue type (bovine or human).

Results

There was no significant difference in R_a between human and bovine incisor enamel at baseline (human 0.11 μm, bovine 0.12 μm P > 0.05), and no significant difference was observed post-erosion (human 0.23 μm, bovine 0.20 μm P > 0.05). There were significant differences in bearing parameters at baseline and post-erosion that were not identified by the R_a measurement alone.

Conclusions

The results suggest that if R_a alone is measured, important differences in surface characteristics may be missed. The null hypothesis is rejected, and the recommendation is made that bearing parameters are included within profile measurements in order to further triangulate the results of surface analysis studies.

Clinical relevance

In isolation, R_a may misrepresent the surface features of a profile. These results have shown that the bearing parameters are an important and informative set of measurements. The recommendation is made that bearing parameters are included within profile measurements at baseline and post-erosion, in order to further triangulate the results of surface analysis studies.