Rehabilitation of Oncology Patients with Hard Palate Defects Part 2: Principles of Obturator Design.

The first part of this series on the conventional rehabilitation of oncology patients with hard palate defects discussed the dental challenges posed by oncology patients and the surgical/restorative planning interface for conventional dental rehabilitation. This article will describe Aramany's classification of hard palate defects, Brown's classification of palatal defects and focus on the basic principles of obturator design which need to be appreciated when prosthetically rehabilitating a patient with a hard palate defect. CPD/CLINICAL RELEVANCE: A good understanding of basic removable prosthodontic theory relating to denture design, dental materials science and head and neck anatomy is a prerequisite when designing an obturator for a patient.

Rehabilitation of oncology patients with hard palate defects. Part 1: The surgical planning phase.

This article is the first in a series of three papers that will discuss the conventional non-implant retained prosthodontic rehabilitation of oncology patients with surgically acquired hard palate defects. In this first paper, the dental challenges posed by the oncology patients will briefly be discussed. The interface between the specialist restorative dentist and the maxillofacial surgeon when planning the conventional dental rehabilitation of an oncology patient with a hard palate defect will be discussed in detail. Clinical Relevance: To highlight the importance of the restorative dentistry/surgical interface when planning a treatment for a patient requiring a maxillectomy and conventional obturation.

Prosthetic rehabilitation of the gagging patient using acrylic training plates.

Patients with a hyper-responsive gag reflex pose dentists with a challenging problem. The gag reflex of some patients may be so severe that patients (and operating clinician) may favour extraction of any painful, infected teeth as opposed to more lengthy and complicated procedures such as root canal therapy. However, consistently adopting this approach may render the gagging patient completely edentulous. Such patients may then present to the dental surgeon requesting tooth replacement with some form of denture. This in itself can be a challenging task given the difficulties one may experience whilst taking impressions in this cohort of patients. This article will discuss the prosthetic management of the maxillary arch in edentulous patients with a severe gag reflex. There will be particular emphasis on the aetiology and physiology of the gag reflex, impression-taking techniques to allow the construction of an acrylic training plate (as an interim measure), principles of training plate design and construction of the definitive removable denture. Clinical Relevance: Removable training plates can be used as an interim measure to desensitize edentulous gagging patients before providing them with a definitive removable denture.

Rehabilitation of Oncology Patients with Hard Palate Defects Part 3: Construction of an Acrylic Hollow Box Obturator.

This article will discuss the clinical stages in the fabrication of a definitive acrylic hollow box obturator to restore a hard palate defect. The first two papers described the restorative/surgical planning phase and the principles of obturator design. CPD/CLINICAL RELEVANCE: Each of the clinical stages required to make a hollow box obturator must be performed to the highest possible standard to ensure than an optimal prosthesis.is fabricated.

Dental Management of a Patient with Multiple Idiopathic Cervical Root Resorption.

Multiple Idiopathic Cervical Root Resorption (MICRR) is a rare condition. It initiates at the cemento-enamel junction of multiple teeth. The lesions continue to grow until they unite, thereby undermining the entire coronal structure of affected teeth. Its distribution can vary from a single region to the entire dentition and the number of teeth affected by resorption tends to increase as the condition is followed over time. The teeth themselves appear clinically normal. The aetiology of MICRR is unknown and it is considered to be a diagnosis of exclusion. The condition tends to be progressive. Consequently, root treatments/surgical curettage and restoration of the lesions have been unsuccessful at arresting the condition. Affected teeth are often extracted in anticipation of catastrophic fracture and have been replaced with partial or complete dentures. In this case report, we describe how a young female patient was dentally managed over 10 years and ultimately rehabilitated with dental implants. CPD/CLINICAL RELEVANCE: Patients suspected of having multiple idiopathic cervical root resorption may require specialist, multidisciplinary care and require referral to an appropriate secondary care unit for treatment planning and potential oral rehabilitation.

Quantifying composite restoration removal and cavity re-preparation using novel region-specific volumetric analysis.

OBJECTIVES: This in-vitro study investigated the effect of 400-405 nm light used during removal of a composite restorations on volume of tooth tissue removed iatrogenically (IATR) and the volume of residual composite. METHODS: Thirty unrestored premolar teeth obtained via a university tissue bank were evenly allocated to test and control groups; material removal with and without violet light. Three clinicians (blinded to the protocol) prepared class V buccal cavities in the teeth. The teeth were scanned using CEREC Omnicam and reallocated to another clinician prior to restoration and rescanning. The teeth were reallocated, and the restorations were removed prior to rescanning. Volumetric scan data was obtained on: changes in cavity volume; the volume of IATR; the volume of residual composite. Data were analysed using Shapiro-Wilk and Kruskal-Wallis tests to a significance of p<0.05. RESULTS: Data showed that there is more IATR when the light was used with mean volume CAV2-over cut of (3.4 mm3, SD 4.22) whereas less IATR was seen when the light was not used (1.2 mm3, SD 1.00), (p<0.05). Data also showed that there is no significant difference in the overall volume of resin composite left when the light was used or not (p> 0.05). However when the light was used, less resin composite material was left around the margins of the cavities when compared to the no light group. SIGNIFICANCE: This novel region-specific cavity analysis method reveals patterns of iatrogenic damage and retained composite which may hold clinical relevance. The use of violet light may result in more complete removal of composite at margins, but also increase IATR. Further research using the novel method is required to ascertain the repeatability and clinical significance of findings.

Reduced-step composite polishing systems - a new gold standard?

OBJECTIVES: To compare the surface gloss and surface roughness of three contemporary composites when polished with reduced-step polishing systems or a conventional multiple-step technique. METHODS: Fifty Discs (8 mm ø x 2 mm) were each fabricated from three composites; Essentia (ES), BRILLIANT EverGlow (EG), and Filtek Universal, (FU). 5 different polishing systems were randomly assigned 10 specimens from each composite group. The 'gold standard' multiple-step system consisted of Sof-Lex XT discs followed by DiaPolisher diamond paste (GC) (P1). The two-step systems were Polishettes (P2) and DIATECH ShapeGuard (P3) and the one-step systems used were; Opti1Step (P4) and OneGloss (P5). Surface gloss was measured using a glossmeter and surface roughness was measured by a profilometer. Statistical analysis was conducted using one-way ANOVA and Pearson correlation tests. Samples were also imaged across different length scales using scanning electron microscopy and macro-lens photography. RESULTS: The highest gloss was obtained when P2 and P3 were used in all composite groups (p < 0.05). EG composite showed the lowest Sa (0.08 µm) when polished with P3 and highest gloss when polished with P2 (96.7 GU). Polishing with P5 resulted in highest Sa and lowest surface gloss in all composite groups (p < 0.05). A high correlation was found between Sa and gloss, r = 0.73 (p < 0.05). Both SEM and macro-lens photography supported quantitative data. CONCLUSION: Both two-step composite polishing systems produced superior gloss compared to the traditional multiple-step polishing system. Mean surface roughness (Sa) and surface gloss are highly correlated with each other. CLINICAL SIGNIFICANCE: Some reduced step composite polishing systems tested in this study produced superior gloss outcomes compared to the traditional gold-standard multi-step polishing system. This may enable significant clinical chair-time reduction and faster polishing protocols.

Development and characterisation of dental composites containing anisotropic fluorapatite bundles and rods.

OBJECTIVES: To develop dental composites incorporating fluorapatite (FA) crystals as a secondary filler and to characterise degree of conversion, key mechanical properties and fluoride release. METHODS: FA rod-like crystals and bundles were hydrothermally synthesised and characterised by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) and 19F MAS-NMR. Composites were formulated containing BisGMA/TEGDMA/BisEMA and barium-aluminium-silicate glass (0FA). FA crystals were incorporated at 10 (10FA), 20 (20FA), 30 (30FA) and 40wt% (40FA) maintaining a filler content of 80wt% (63-67vol%). Degree of conversion (DC), flexural strength (FS), flexural modulus (FM), fracture toughness (K1C), Vickers hardness (HV) and 2-body wear were measured. Fluoride release was measured in neutral and acidic buffers. RESULTS: XRD and 19F MAS-NMR confirmed that only FA was formed, whilst SEM revealed the presence of single rods and bundles of nano-rods. DC ranged between 56-60% (p>0.05). FA composites showed lower FM and lower FS (p<0.05), but comparable wear resistance and HV (p>0.05) to 0FA. 30FA and 40FA showed similar K1C to 0FA (p>0.05), with SEM showing evidence of toughening mechanisms, whereas 10FA and 20FA showed lower K1C (p<0.05). FA containing composites released fluoride that was proportional to the amount of FA incorporated (p<0.05) but only under acidic conditions. SIGNIFICANCE: The addition of FA to the experimental composites reduced strength and stiffness but not the DC, hardness or wear rate. 30FA and 40FA had a higher K1C compared to other FA groups. Fluoride release occurred under an accelerated acidic regime, suggesting potential as a bioactive 'smart' composite.

An approach to understanding tribological behaviour of dental composites through volumetric wear loss and wear mechanism determination; beyond material ranking.

OBJECTIVE: To investigate the fundamental wear mechanisms of six resin-based composite (RBC) formulations during short-term in vitro wear testing. MATERIALS: RBC materials were condensed into rectangular bar-shaped specimens and light irradiated using the ISO 4049 specimen manufacture and irradiation protocol. Wear testing (n=10 specimens for each RBC) was performed on a modified pin-on-plate wear test apparatus and wear facets were analysed for wear volume loss using a white light profilometer. The wear tested RBC specimens and their corresponding antagonists were analysed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively to determine the wear mechanism. RESULTS: Data generated using the profilometer showed variations in the mean total wear volume (mm3) between the RBCs tested (p<0.05). Abrasive wear was evident in all RBCs investigated with varying degrees of damage. Material transfer/deposition of the filler particles on the corresponding antagonists was evident in two RBC materials (Filtek Supreme and Kalore) indicative of a further adhesive wear mechanism. CONCLUSION: It is proposed that the approach employed to use a combination of measurement and analytical techniques to quantify the wear facet volume (profilometry), wear trough (SEM) and material transfer (EDS) provides more useful information on the wear mechanism and the tribology of the system rather than relying on a simple wear ranking for the RBC materials as is routinely the case in dental research studies.