Erosive tooth wear: a multifactorial condition of growing concern and increasing knowledge.

Dental erosion is often described solely as a surface phenomenon, unlike caries where it has been established that the destructive effects involve both the surface and the subsurface region. However, besides removal of the surface, erosion shows dissolution of mineral within the softened layer - beneath the surface. In order to distinguish this process from the carious process it is now called 'near surface demineralization'. Erosion occurs in low pH, but there is no fixed critical pH value concerning dental erosion. The critical pH value for enamel concerning caries (pH 5.5-5.7) has to be calculated from calcium and phosphate concentrations of plaque fluid. In the context of dental erosion, the critical pH value is calculated from the calcium and phosphate concentrations in the erosive solution itself. Thus, critical pH for enamel with regard to erosion will vary according to the erosive solution. Erosive tooth wear is becoming increasingly significant in the management of the long-term health of the dentition. What is considered as an acceptable amount of wear is dependent on the anticipated lifespan of the dentition and is, therefore, different for deciduous compared to permanent teeth. However, erosive damage to the teeth may compromise the patient's dentition for their entire lifetime and may require repeated and increasingly complex and expensive restorations. Therefore, it is important that diagnosis of the tooth wear process in children and adults is made early and that adequate preventive measures are undertaken. These measures can only be initiated when the risk factors are known and interactions between them are present.

Restorative therapy of erosive lesions.

When substance loss caused by erosive tooth wear reaches a certain degree, oral rehabilitation becomes necessary. Until some 20 years ago, the severely eroded dentition could only be rehabilitated by the provision of extensive crown and bridge work or removable overdentures. As a result of the improvements in resin composite restorative materials, and in adhesive techniques, it has become possible to rehabilitate eroded dentitions in a less invasive manner. However, even today advanced erosive destruction requires the placement of more extensive restorations such as overlays and crowns. It has to be kept in mind that the etiology of the erosive lesions needs to be determined in order to halt the disease, otherwise the erosive process will continue to destroy tooth substance. This overview presents aspects concerning the restorative materials as well as the treatment options available to rehabilitate patients with erosive tooth wear, from minimally invasive direct composite reconstructions to adhesively retained all-ceramic restorations. Restorative treatment is dependent on individual circumstances and the perceived needs and concerns of the patient. Long-term success is only possible when the cause is eliminated. In all situations, the restorative preparations have to follow the principles of minimally invasive treatment.

Systematic literature review of digital three-dimensional superimposition techniques to create virtual dental patients

PURPOSE Digital developments have led to the opportunity to compose simulated patient models based on three-dimensional (3D) skeletal, facial, and dental imaging. The aim of this systematic review is to provide an update on the current knowledge, to report on the technical progress in the field of 3D virtual patient science, and to identify further research needs to accomplish clinical translation. MATERIALS AND METHODS Searches were performed electronically (MEDLINE and OVID) and manually up to March 2014 for studies of 3D fusion imaging to create a virtual dental patient. Inclusion criteria were limited to human studies reporting on the technical protocol for superimposition of at least two different 3D data sets and medical field of interest. RESULTS Of the 403 titles originally retrieved, 51 abstracts and, subsequently, 21 full texts were selected for review. Of the 21 full texts, 18 studies were included in the systematic review. Most of the investigations were designed as feasibility studies. Three different types of 3D data were identified for simulation: facial skeleton, extraoral soft tissue, and dentition. A total of 112 patients were investigated in the development of 3D virtual models. CONCLUSION Superimposition of data on the facial skeleton, soft tissue, and/or dentition is a feasible technique to create a virtual patient under static conditions. Three-dimensional image fusion is of interest and importance in all fields of dental medicine. Future research should focus on the real-time replication of a human head, including dynamic movements, capturing data in a single step.