Occlusal overload during sleep is a significant clinical issue that has negative impacts on the maintenance of teeth and the longevity of dental prostheses. Sleep is usually viewed as an 'out-of-functional' mode for masticatory muscles. However, orodental structures and prostheses are not free from occlusal loads during sleep since masticatory muscles can be activated at a low level within normal sleep continuity. Thus, an increase in masticatory muscle contractions, by whatever the cause, can be associated with a risk of increased occlusal loads during sleep. Among such conditions, sleep bruxism (SB) is a type of sleep-related movement disorders with potential load challenge to the tooth and orofacial structures. Patients with SB usually report frequent tooth grinding noises during sleep and there is a consecutive increase in number and strength of rhythmic masticatory muscle activity (RMMA). Other types of masticatory muscle contractions can be non-specifically activated during sleep, such as brief contractions with tooth tapping, sleep talking, non-rhythmic contractions related to non-specific bodymovements, etc.; these occur more frequently in sleep disorders. Studies have shown that clinical signs and symptoms of SB can be found in patients with sleep disorders. In addition, sleep becomes compromisedwith aging process, and a prevalence of most sleep disorders is high in the elderly populations, in which prosthodontic rehabilitations are more required. Therefore, the recognition and understanding of the role of sleep disorders can provide a comprehensive vision for prosthodontic rehabilitations when prosthodontistsmanage complex orodental cases needing interdisciplinary collaborations between dentistry and sleep medicine.

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Purpose: A Vickers hardness indenter was pressed into yttria-stabilized zirconia (Y-TZP) by the indentation fracture method (IF method).
Methods: The effect on the calculated Vickers hardness, fracture toughness values, and indentation fracture load (9.8, 49, 98, 196, and 294 N) was examined to deduce the optimum conditions of the IF method. Calculated Vickers hardness and fracture toughness values were analyzed with one-way analysis of variance and then multiple comparisons (Scheffe). The appearance of on indentation and cracks was also evaluated using a scanning electron microscopy (SEM).
Results: Indentation of Y-TZP was generated by 9.8 and 49 N of indentation fracture load, however cracks could not be confirmed with the microscope attached to the Vickers hardness tester. Both indentation and cracks were observed at 98, 196 and 294 N of indentation fracture load obtained values of 7.1 and 6.8 MPam^1/2. Cracks noted at the 98 N were not clear, whereas the 196 and 294 N showed especially clear cracks. Due to the hardness of zirconia and the light loads, fracture toughness values for 9.8, 49, and 98 N could not be calculated. There was no significant difference between 196 and 294 N, when calculated fracture toughness values were analyzed with multiple comparisons. SEM revealed clear indentation and cracks, that extended linearly, but no chips or fractures were observed. Surface changes were observed at 196 and 294 N that are presumed to be accompanied by phase transition around the cracks.
Conclusions: Optimum experimental conditions of the indentation fracture load in the IF method were determined as 196 and 294 N.

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Purpose: The purpose of the present study was to compare the effectiveness of an isocyanate monomer and four different silane monomers as primer components for bonding a leucite-reinforced glass ceramic (GN-Ceram Block).
Methods: Four different methyl-methacrylate based primers, each with three different concentrations (1, 4, or 16wt%) of 2-methacryloxyethylisocyanate (MOI), 3-methacryloxypropylmethyldimethoxysilane (MDS), 3-methacryloxypropyltrimethoxysilane (MTS), and 3-acryloxypropyltrimethoxysilane (ATS) were prepared. A commercially available silane primer (ESPE™Sil) was also used as a control. The GN-Ceram Block specimen was ground with silicon carbide paper, rinsed, primed, and then bonded to a resin composite disk using a tri-n-butylborane-initiated self-curing luting agent. After 24-h immersion in water, the shear bond strengths were determined.
Results: The highest level of bond strength was obtained with 4wt% MTS (45.2 MPa) and 4wt% ATS (38.7 MPa), followed by 4wt% MOI (29.8 MPa), ESPE™Sil (28.1 MPa), and 4wt% MDS (27.9 MPa). For each MTS, ATS, MOI, and MDS, the bond strengths for concentrations of 4wt% and 16wt% were not significantly different. No significant differences were found between 4wt% ATS, 4wt% MOI, ESPE™Sil, and 4wt% MDS. The use of any of these primers led to a significant increase in bond strength compared to an unprimed control (13.8 MPa).
Conclusions: The type and concentration of monomers dissolved in the primer influence the bond strength between a tri-n-butylborane resin and a leucite-reinforced glass ceramic GN-Ceram Block. The effectiveness of MOI was found to be comparable to that of MDS, ATS, and ESPE™Sil, but inferior to that of MTS.

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Purpose: Low-intensity pulsed ultrasound (LIPUS) has been used in fracture treatment to shorten the time needed for biological wound healing. However, the influence of LIPUS exposure on oral wound healing has not been sufficiently investigated. This study was conducted to evaluate low-intensity pulsed ultrasound on wound healing in palatal excisional wounds of rats.
Methods: Excisional wounds, 5 mm in diameter, were made in the center of the palate of rats. Animals were divided into four experimental and control groups (1-week after LIPUS exposure, 1-week control, 2-week after LIPUS exposure, and 2-week control). The affected area in the experimental group was exposed to LIPUS, daily frequency: 3 MHz, intensity: 160 mW, exposure time: 15 min. Specimens were fixed in 10% neutral formalin solution immediately after sacrifice. The wound was measured histologically.
Results: Wound width in the LIPUS group tended to be smaller than that of the control group. The experimental group in both 1-week and 2-week groups showed that unhealed areas were significantly smaller by LIPUS than those in the control groups (P < 0.05).
Conclusion: Our results suggest that the use of LIPUS on palatal excisional wounds was effective in promoting epithelial and connective tissue closure.

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Purpose: Peri-implant epithelium associated with the structure of the internal basal lamina is in contact with a transmucosal portion of the endosseous implant surface. This contact is important to protect the many complex factors required for the long-term stability and maintenance of the implant. This study investigated the effect of initial adhesion of gingival epithelial cells to anodized-hydrothermally treated commercially pure titanium with nanotopographic structure (SA-treated c.p.Ti). Changes in cell morphology and gene expression of integrin-α6β4 and laminin-5 were assessed.
Methods: Murine immortalized gingival epithelial (GE1) cells were cultured for 1–3 days on c.p.Ti, anodic oxide (AO) c.p.Ti, and SA-treated c.p.Ti disks. Cell morphology was analyzed using scanning electron microscopy (SEM). Cell proliferation was analyzed using the WST-1 assay. Integrin-α6β4 and laminin-5 (α3, β3, γ2) mRNA levels were measured using real-time quantitative RT-PCR.
Results: The GE1 cells appeared flattened with extensions on all disks by SEM analysis. Filopodium-like extensions were bound closely to the nanotopographic structure surface of SA-treated c.p.Ti especially at day 3 of culture. GE1 cell proliferation as well as the expression of integrin-α6β4 and laminin-5 (α3, β3, γ2) mRNAs was significantly higher on SA-treated c.p.Ti than on c.p.Ti and AO c.p.Ti disks after 3 days (P < 0.05).
Conclusions: Gingival epithelial cells initially attach to a transmucosal portion of SA-treated c.p.Ti implant material and subsequently express the integrin-α6β4 adhesion molecule and the laminin-5 extracellular matrix molecule. This cell behavior may play a key role in maintaining the peri-implant oral mucosal tissue barrier.

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Purpose: This study explored the relationship between implant support and the denture-supporting area by comparing the stability of an implant-supported distal extension removable partial denture and a conventional distal extension removable partial denture.
Methods: A model simulating a mandibular bilateral distal extension missing (#34–37 and #44–47) was fabricated using silicone impression material as soft tissue (2 mm thick) on an epoxy resin bone model. The denture base was reduced by 5 mm cutting part of both the retromolar pad and the lingual border. Loads of up to 5 kg were applied, and the pressure and displacement of the RPDs were simultaneously measured and analyzed using the Wilcoxon test (α < 0.05).
Results: The pressure on the bilateral first molar and the middle areas of the implant-supported distal extension removable partial denture (ISRPD) was significantly less than on the conventional RPD (CRPD). As the supporting area of the denture base decreased, the pressure and the denture displacement of the CRPD were greater than for the ISRPD.
Conclusion: This study indicated that implant placement at the distal edentulous ridge can prevent denture displacement of the distal extension bases, regardless of the supporting area of the denture base.

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Purpose: This study aimed to examine changes in the lip form, oral fissure form and vermilion height of complete denture wearers resulting from altered occlusal vertical dimension (OVD) and/or lip support.
Methods: Three-dimensional facial images of 10 edentulous patients (four males and six females) when wearing six experimental record blocks (ExpRBs) with varying OVD and/or lip support were analyzed. Analysis was performed using three landmarks on the mid-line (labrale superius (ls), stomion (sto), and labrale inferius (li)) and two landmarks on the oral fissure (at points 20 mm right and left of the midline (r-OFP and l-OFP, respectively)). Curvature of the oral fissure (COF) in the frontal view was evaluated by calculating the difference between sto and the average of r-OFP and l-OFP (avrl-OFP). The vermilion height in the frontal view was calculated as the distance from sto to ls and li. In 10 subjects, comparison between standard ExpRB and test ExpRBs with altered OVD and/or lip support was performed by calculating differences between these data.
Results: The ls, sto, and li landmarks changed with alteration of OVD and/or lip support, whereas avrl-OFP changed vertically with alteration of lip support and anteroposteriorly with alteration of OVD and/or lip support. COF and vermilion height were affected by alterations in OVD and/or lip support.
Conclusion: Deficient OVD with extensive lip support can curve the oral fissure form upward, and deficient OVD with deficient lip support can reduce the vermilion height.

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Introduction: The conventional 2D-analysis methods for occlusal contacts provided limited information on tooth morphology. This present study aims to detect 3D positional information of occlusal contacts from 2D-photos via photogrammetry. We propose an image processing solution for analysis of occlusal contacts and facets via the black silicone method and a photogrammetric technique.
Materials and methods: The occlusal facets were reconstructed from a 2D-photograph data-set of inter-occlusal records into a 3D image via photogrammetry. The configuration of the occlusal surface was reproduced with polygons. In addition, the textures of the occlusal contacts were mapped to each polygon.
Difference from conventional methods: Constructing occlusal facets with 3D polygons from 2D-photos with photogrammetry was a defining characteristic of this image processing technique. It allowed us to better observe findings of the black silicone method. Compared with conventional 3D analysis using a 3D scanner, our 3D models did not reproduce the detail of the anatomical configuration. However, by merging the findings of the inter-occlusal record, the deformation of mandible and the displacement of periodontal ligaments under occlusal force were reflected in our model.
Effect or performance: Through the use of polygons in the conversion of 2D images to 3D images, we were able to define the relation between the location and direction of the occlusal contacts and facets, which was difficult to detect via conventional methods.
Conclusion: Through our method of making a 3D polygon model, the findings of inter-occlusal records which reflected the jaw/teeth behavior under occlusal force could be observed 3-dimensionally.

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Background: Loss of tissue, whether congenital or traumatic or resulting from malignancy or radical surgery, is accompanied by esthetic and psychological effects. Fabrication of an ocular prosthesis is a challenging and time-consuming procedure.
Patients and techniques: This article describes two different techniques of iris customization on two different patients. First technique describes the iris customization with the use of conventional paint on technique while second describes the photographic method of fabricating the eye prosthesis.
Discussion: A sequence of steps of construction of ocular prostheses is outlined, and the critical areas of fabrication and artistic techniques employed in the successful prosthetic treatment are described in this article. Conventional iris paint on technique and digital photographic technique to customize the iris are explained along with their advantages, disadvantages and indications.
Conclusion: In addition to decrease treatment time and increased simplicity, digital photography technique is particularly advantageous in cases requiring thin acrylic shell type of prosthesis.

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Patient: This article describes a case report of a patient with history of bilateral orbital exenteration due to squamous cell carcinoma. Spectacle retained acrylic prosthesis was considered to be the best possible option in this case due to total lack of vision and related manual dexterity.
Discussion: Main challenge in fabrication of spectacle retained prosthesis is to maintain its adaptation with the tissues during attachment of the screws. So, method of attachment of prostheses with the frame has been discussed in detail. The other concern was the increased weight of the prosthesis and associated discomfort to the patient, as both artificial eyes had to be attached to one frame. Therefore, procedure to reduce the weight of the prosthesis is also discussed.
Conclusion: Successful prosthodontic rehabilitation is based on the selection of most suitable maxillofacial prosthetic material and appropriate retentive aid for each patient. Though spectacle retained acrylic prosthesis is a conventional method, it was a user friendly and economical option for this patient.

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Patient: The patient was a 62-year-old partially edentulous woman with missing bilateral premolars and molars in the mandibular jaw. The patient selected implant supported-removable partial denture rehabilitation. Implants were placed bilaterally at the distal extension of the denture base in order to minimize denture displacement. The stress-breaking ball (SBB) attachment consists of a flat-top ball head male and O-ring rubber female. The female was covered by a silicone housing with three amounts of space to allow three kinds of settlement (0.3 mm, 0.5 mm, and 0.7 mm); they were selected by thickness or pressure displacement of the mucosa and occlusal force. After the healing period, the SBB attachments (0.3 mm) were placed on the implants, and the implant-supported removable partial denture was then conventionally fabricated. The delivered denture had sufficient retention and appropriate stress breaking.
Discussion: The advantages of SBB attachments over conventional attachments are as follows: (1) they prevent the implant from excessive occlusal force, (2) they are ready-made, (3) they show appropriate retention, and (4) they can be easily mounted on the denture base. The disadvantages of these attachments are as follows: (1) they are approximately 1 mm higher than conventional ball attachments and (2) the retentive force cannot be adjusted.
Conclusion: The use of a stress-breaking attachment for implant overdenture rehabilitation should be considered so that the occlusal force is equally distributed between the alveolar ridge and the implants.

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