Panagiotis Zoidis

The Use of a Modified Poly-Ether-Ether-Ketone (PEEK) as an Alternative Framework Material for Removable Dental Prostheses. A Clinical Report.

This clinical report presents a modified poly-ether-ether-ketone (PEEK) as an alternative material for the fabrication of distal extension removable dental prosthesis (RDP) frameworks. This material can be used for patients allergic to metals, or who dislike the metallic taste, the weight, and the unpleasant metal display of the denture framework and retentive clasps. This modified PEEK material, known as BioHPP, is a biocompatible, nonallergic, rigid material, with flexibility comparable to bone, high polishing and low absorption properties, low plaque affinity, and good wear resistance. It has been used for years in orthopedics and medical technology. BioHPP frameworks can be constructed either via CAD/CAM manufacturing or via the conventional lost wax technique. The clinical use of a BioHPP RDP framework is presented as an alternative for the treatment of a distal extension case.

The Effect Of Soldering, Electrowelding, And Cast-to Procedures On The Accuracy Of Fit Of Cast Implant Bars

The effect of three different connecting procedures on the accuracy of fit of cast implant bars over their supporting abutments was investigated. Thirty Hader implant bars were waxed on a master cast over two abutment analogs and cast in a type IV gold alloy. The bars were sectioned and divided into three groups of ten implant bars according to the connecting procedure that was to be followed. Group 1 bars were connected by soldering, Group 2 bars were connected by electrowelding, and Group 3 bars were connected with the cast-to procedure. The accuracy of fit of each group of bars was measured at the gold cylinder-abutment interface in microns using a stereomicroscope. The use of the cast-to procedure resulted in a more accurate fit as compared with the soldering and the electrowelding techniques.

Modified PEEK Resin Bonded Fixed Dental Prosthesis for a Young Cleft Lip and Palate Patient

OBJECTIVE This clinical report presents the use of a modified poly ether-ether ketone material as an alternative material for the fabrication of resin-bonded fixed dental prosthesis (RBFDP) framework. This new material can be used for patients allergic to metals, maintaining the same high esthetic demand of ceramics, presenting light weightness and a flexibility similar to bone as a distinct advantage over ceramic materials. CONCLUSIONS The use of a BioHPP RBFDP framework could be considered as an alternative restoration for the replacement of missing lateral incisors in young patients with cleft palate defects. CLINICAL SIGNIFICANCE This modified PEEK material known as BioHPP, is a biocompatible, non allergic, rigid material with good mechanical properties, wear resistance, chemical stability, high polishing and low absorption properties. BioHPP frameworks can be manufactured either via CAD/CAM or via the conventional lost wax technique. The low modulus of elasticity, combined with the use of indirect composite resin as a veneering material, provide a distinct advantage over ceramics or metal ceramics on dampening the occlusal forces, reducing the risk of debonding. (J Esthet Restor Dent 28:201-207, 2016).

Modified PEEK resin-bonded fixed dental prosthesis as an interim restoration after implant placement

A polyetheretherketone (PEEK) (BioHPP) framework veneered with composite resin was used as an alternative material for the fabrication of an interim 3-pontic resin-bonded fixed dental prosthesis (RBFDP) after implant placement. The low modulus of elasticity (4 GPa) of PEEK combined with the use of indirect light-polymerized resin as a veneering material used for a RBFDP provided an advantage over metal ceramics or ceramics in dampening the occlusal forces and reducing debonding rates. Further long-term clinical evidence is required before recommending the application as a substitute material.

A simplified method for measuring photomicrographs.

An accurate technique that simplifies measurements of two- and three-dimensional specimens is presented. Photomicrographs of a microruler and of the specimens of a research project were made at the same magnification. A ruler with the exact dimensions of the photographic prints of the microruler was generated through computer graphics and printed as a transparency. After verification, the ruler was used to measure specimens directly on the photomicrographs.

Short-Term Assessment of the OHIP-14 Scale on Denture Wearers Using Adhesives

PURPOSE The purpose of this study was to assess differences of the Oral Health Implant Profile-14 (OHIP-14) scale over a month and determine association with gender, supporting tissues (KIS), and denture base (KID) among patients wearing complete dentures using denture adhesives. MATERIALS AND METHODS Sixteen denture wearers, candidates for a new set of complete dentures, were selected. OHIP-14 scores were recorded at the beginning of the study, 6 weeks after fitting of the new set (T0 ), 15 days (T1 ), and finally 30 days (T2 ) after daily use of a denture adhesive as instructed. The KIS and KID were clinically examined and rated according to the Kapur Index. Statistical analyses were based on repeated-measures ANOVA, Mann-Whitney test, regression analysis, and Friedman test at a = 0.05. RESULTS The OHIP-14 scale was found to have a high reliability (alpha = 0.847) and a high test-retest consistency (ICC = 0.889); however, domain 1 had the lowest item-total correlation (rho = 0.144) and item 7 a negative one (rho = -0.414). Trend analysis indicated a significant negative linear trend over time (slope = -3.156, p = 0.002), while repeated-measures ANOVA showed differences in OHIP-14 between T2 and T1 (p = 0.003) or T0 (p = 0.005) intervals. OHIP-14 groups were found to be positively associated with KIS (p = 0.010) and negatively with KID (p = 0.047) groups, but not with gender (p = 0.272). CONCLUSIONS The study shows that OHIP-14 has a high internal reliability and consistency when applied to new denture wearers, and its score decreases if denture adhesives are used for at least 15 days. Low KIS and high KID contributes to this trend. Some OHIP-14 items are more associated than others with the total score trend over time.

Removable Dental Prosthesis Splint. An Occlusal Device for Nocturnal Bruxing Partial Denture Users

Nocturnal bruxing is a parafunctional activity of the masticatory system that may create problems for removable dental prosthesis (RDP) users. Such problems may include root fractures, increased mobility of abutment teeth, excessive wear of resin denture teeth, minor connector bending, or denture base cracking. This clinical report presents an occlusal device fabricated for an RDP patient. The device used existing ERA attachments for added retention designed with the intended purpose of protecting the definitive fixed and RDP from damage due to nocturnal bruxing activity and providing for even distribution of parafunctional forces.

Evaluation of a Realistic Cleansing Protocol for Preventing Discoloration of Denture Resins: Protocol for Preventing Discoloration of Denture Resins

PURPOSE To evaluate the efficacy of a realistic staining/cleansing protocol for long-term prevention of discoloration of denture base resins. MATERIALS AND METHODS Sixty discs (20 × 2.5 mm) of auto- and heat-polymerizing denture acrylic resins were fabricated following manufacturers instructions, polished on one side and stored in water (37°C) for 24 hours before they were assigned randomly into 6 groups (3 for each material, n = 10) to receive 220 cycles of three immersion protocols. Group A was immersed in the following baths: (1) filtered coffee at 45°C for 2 minutes, (2) tap water at 24°C for 20 seconds, (3) as bath 1, (4) as bath 2, (5) Corega Extradent cleansing solution at 45°C for 3 minutes, and (6) water at 24°C for 20 seconds. Group B was immersed in the four first baths of group A (without cleansing action) and group C in bath 1 for the cumulative action of 20 cycles (80 minutes in 45°C coffee) and bath 2 for 40 seconds. A noncontact optical interferometric profilometer was used for qualitative evaluation of the specimens and a contact colorimeter to estimate color change values (ΔΕ*ab) at baseline and every 20 cycles in the baths for a total of 220 cycles. Data were statistically analyzed using a 2-way-repeated measures ANOVA with Bonferoni multiple comparisons and trend analysis at α = 0.05 level of significance. RESULTS Data indicated changes in color from 1.7 to 14.2 ΔΕ*ab units. The highest values were related to the number of cycles and group B immersion protocol. Significant differences were found among immersion protocols (p < 0.001) and immersion cycles (p < 0.001) with a significant interaction between protocols and cycles (p < 0.001) but not between denture resins (p = 0.991). CONCLUSION The evaluated protocol A was found effective in preventing color changes in both denture resins even after a long period of action. Protocol C had a much lower staining effect on both resins than protocol B and behaved similarly to protocol A until 140 to 160 cycles. Therefore, it is probably not appropriate for use in short-term color stability experiments.

Polyetheretherketone Overlay Prosthesis over High Noble Ball Attachments to Overcome Base Metal Sensitivity: A Clinical Report: PEEK Overdenture Framework

A modified polyetheretherketone (PEEK) framework material in combination with heat-polymerized denture base acrylic resin was used for the fabrication of an overlay prosthesis for a patient sensitive to base metals. High noble metal was used for the fabrication of the post/coping/ball attachment assemblies to promote retention and stability. These protruding attachments into the acrylic resin could result in stress concentration; therefore, a framework is often used to strengthen the prosthesis. PEEK frameworks could be a treatment alternative to high noble or Ti frameworks since they combine good mechanical properties with biocompatibility, reduced cost, and common laboratory procedures.

A Fixed Telescopic Prosthesis Designed to Retrieve and Convert to Fixed-Removable Combination Case: A Clinical Report

This clinical report describes a fixed maxillary telescopic dental prosthesis (FTDP) employing milled base metal copings and a metal superstructure veneered with composite resin, for the restoration in a periodontally compromised patient with uncontrolled diabetes. The telescopic prosthesis framework design incorporated occlusal rest seats in key positions along the arch in case of future posterior tooth loss, in order to be converted to fixed - removable combination prosthesis. The mandible was restored with a conventional fixed ceramo-metal dental prosthesis.