Prosthet Dent Research Articles

Contrast ratios and masking ability of three types of ceramic veneers

Although ceramic veneers have been proven to be clinically successful in longevity studies, there is little information on the contrast ratios and masking ability of the available ceramic systems because dental laboratory technology and expensive experimental equipment are required for the investigation. Moreover, the complexity in understanding how to evaluate translucent ceramic materials may also explain why information in this area is limited. The purpose of this study was to determine the contrast ratios and masking abilities of 3 types of all-ceramic veneers by measuring their luminance and color difference over white and black backgrounds. Disk-shaped specimens (8-mm diameter x 0.7-mm thickness) of Shade A2 (Vita Lumin) of 3 types of all-ceramic systems: Procera (n=8), Empress 2 (n=8), and Vitadur Alpha (n=10) were fabricated. The luminance (as Y) and color (as CIE L*a*b*) of the specimens were measured with a colorimeter. The contrast ratio (CR=Yb/Yw), defined as the ratio of illuminance (Y) of the test material when it is placed on the black background (Yb) to the illuminance of the same material when it is placed over a white background (Yw), was determined. The masking ability of a specimen was evaluated by calculating the color difference (DeltaE) of the veneers over white and black backgrounds. Both CR and DeltaE* data were analyzed with 1-way ANOVA and the Tukey HSD test (alpha=.05). The mean contrast ratios (SD) of Procera, Empress 2, and Vitadur Alpha specimens were 0.50 (0.02), 0.46 (0.05), and 0.39 (0.02), respectively. CR values were significantly different among the 3 materials (P<.001). Procera veneers had a significantly higher CR compared to Empress 2 (P=.01) or Vitadur Alpha (P=.01), whereas the CR of Empress 2 was significantly higher than that of Vitadur Alpha (P=.046). Color difference (DeltaE*) (SD) of Procera, Empress 2, and Vitadur Alpha specimens over black and white backgrounds were 24.46 (1.03), 25.80 (1.03), and 31.08 (1.19), respectively. DeltaE* values were statistically different among the 3 materials (P<.001). Vitadur Alpha specimens had significantly higher DeltaE* when compared with Procera (P<.001) or Empress 2 (P<.001), whereas DeltaE* values between Procera and Empress 2 were not significantly different (P=.331). Vitadur Alpha had significantly lower contrast ratio and poorer masking ability compared to Procera or Empress 2. The clinical application of Vitadur Alpha as a veneer material over discolored teeth is cautioned. Although the contrast ratio of Procera was significantly higher than that of Empress 2, the masking abilities of these materials were not significantly different. The clinical application of these 2 ceramics as a veneer material may still be limited when applied over intense tooth discoloration because neither can fully mask the color of a black background.

Immediate dentin sealing supports delayed restoration placement

Immediate dentin sealing (IDS) is a new approach in indirect restorations. Dentin is sealed immediately following tooth preparation, prior to impression making. It is not known whether it is still possible to obtain an efficient bond between the resin-coated dentin and the restoration after 2 to 4 months of placement of provisional restorations. The purpose of this study was to determine if there were differences in microtensile bond strength to human dentin using the IDS technique when comparing 2, 7, and 12 weeks of delay until restoration placement, using 2 different dentin bonding agents (DBAs). Previously published preliminary IDS data were included for comparison. Fifty freshly extracted human molars were obtained and divided into 10 groups. A 3-step etch-and-rinse DBA (Optibond FL) and a 2-step self-etching DBA (SE Bond) were used. For each DBA, the control (C) specimens were prepared using a direct immediate bonding technique and composite restoration (Z100). Preparation of the other specimens used an indirect approach without dentin prebonding (delayed dentin sealing, DDS) or with immediate dentin sealing (IDS), immediately following preparation. IDS teeth had provisional restorations (Tempfil inlay) placed for 2 weeks (IDS-2W), 7 weeks (IDS-7W), or 12 weeks (IDS-12W) before restoration placement. All teeth were prepared for a nontrimming microtensile bond strength test (MTBS) 24 hours after definitive restoration with composite overlays (Z100). Ten to 11 beams (0.9 x 0.9 x 11 mm) from each tooth were selected for testing. MTBS data obtained from the 10 experimental groups were analyzed with a 2-way analysis of variance (ANOVA, dentin bonding system, and sequence of application) with each tooth (mean MTBS from the 10-11 beams) used as a single measurement. The Tukey HSD post hoc test was used to detect pairwise differences among experimental groups (alpha=.05). Fractured beams were also analyzed under stereoscopic microscope (x 30) and SEM. For both adhesives, the mean microtensile bond strengths of C and all IDS groups were not significantly different and exceeded 45 MPa. DDS groups exhibited lower bond strength than all others sequences (P<.001) with SE Bond at 1.81 MPa significantly lower (P=.026) than Optibond FL at 11.58 MPa. The highest mean microtensile bond strength values were found with Optibond FL at 7 weeks (66.59 MPa) and 12 weeks (59.11 MPa). These were significantly higher than SE Bond in the same conditions with values of 51.96 MPa and 45.76 MPa (P=.001 and P=.003), respectively. Failures in DDS groups were all interfacial and purely adhesive. Both C and IDS-2W groups demonstrated interfacial failure that was typically mixed with both areas of failed adhesive resin and areas of cohesively failed dentin while IDS-7W and IDS-12W failed consistently between the existing resin coating (used during IDS) and the overlaying composite resin. When preparing teeth for indirect bonded restorations, IDS with a 3-step etch-rinse or a 2-step self-etching DBA (prior to impression making) results in microtensile bond strength similar to that obtained with a freshly placed adhesive. The bond strength is not affected by up to 12 weeks of elapsed time prior to placement of the definitive restoration.

Coverage error of three conceptually different shade guide systems to vital unrestored dentition

It remains unclear which shade guide system is most representative of the shades found in the human dentition. The purpose of this study was to determine and to compare the coverage errors (CEs) of 3 different shades in a selected population. The coverage errors of the following shade guide systems were evaluated to determine which shade guide system is most effective in producing the best visual shade match: (1) Vita Lumin, (2) Chromascop, (3) Vitapan 3D Master, and (4) a combination of the 3 shade guide systems. The spectral reflectance values of the central one ninth (1-mm diameter) of each shade tab (without a backing) were measured with a spectroradiometer and an external light source at wavelengths from 380 nm to 780 nm at 2-nm intervals. All spectral reflectance measurements were made using 0-degree observer and 45-degree illumination and then converted to CIE values. The color values of 359 anterior teeth were measured with the same protocol. The CEs for each of the 359 anterior teeth for each shade guide system, and with all 3 shade guide systems, were determined and averaged. Repeated measure ANOVA was used to evaluate the mean minimum CEs within-subject (shade guide system) and between-subject (age) difference as well as the interaction between these variables (alpha=.05). Then, a post hoc multiple comparison was performed using the Tukey-Kramer test. A significant difference (P<.001) was found among the mean minimum CEs of the 3 shade guide systems and their combination, but not between age groups (P=.384). An interaction was found between shade guide systems and age (P<.001). The Tukey-Kramer test revealed that the mean minimum CEs for Vita Lumin (5.39 DeltaE) and Chromoscop (5.28 DeltaE) shade guide systems were not significantly different from each other. However, the combination of all 3 shade guide systems (3.69 DeltaE) and Vitapan 3D Master (3.93 DeltaE) were significantly different from the Vita Lumin and Chromoscop shade guide system. The rankings of the shade guide systems within each age group were similar between the age groups. The Vitapan 3D Master shade guide system resulted in the lowest coverage errors compared to the Vita Lumin or Chromascop shade guide systems. Coverage errors for the Vitapan 3D Master shade guide system did not differ significantly from the coverage errors when all 3 shade guide systems were combined.

Effect of metal type and surface treatment on in vitro tensile strength of copings cemented to minimally retentive preparations

Due to the potential lack of ideal preparation form, the type of alloy and its surface pretreatment may have clinically relevant correlations with the retentive strength of castings to minimally retentive preparations. The purpose of this study was to evaluate the effect of alloy type and surface pretreatments of base and noble metal copings on their tensile strength to minimally retentive preparations. Minimally retentive, standardized crown preparations were made on recently extracted human third molars (n=68). Noble (IPS d.SIGN 53) and base metal (Rexillium NBF) copings were fabricated. All copings received heat treatment for oxide formation. Three experimental groups were then developed for each metal type (groups ranging from 10 to 12 specimens each): oxide only, airborne-particle abraded, or metal-primed. Copings were cemented using a self-adhesive universal resin cement (RelyX Unicem) and were thermal cycled (500 cycles between 5 and 55 degrees C) and stored (24 hours, 37 degrees C) before debonding using a universal testing machine. Frequency of debond location was compared among specimen groups. A 2-way ANOVA was used to test for interaction between the metal type and surface treatment, and, if no significant interaction was found, to test the main effects for metal type and surface treatment (alpha=.05). A multinomial logit model using the likelihood ratio test was used to describe the effect of metal type and surface treatment on failure site location (alpha=.05). The 2-way ANOVA indicated no significant influence of any factor on debond load: metal type (P=.885), surface treatment (P=.555), or their interaction (P=.644). The multinomial logit statistical model showed that noble metals and metal primers significantly (P<.05) shifted debond failures to occur more frequently at the resin/tooth interface or within the tooth itself. Neither metal type nor surface pretreatment affected bond strength. However, alloy type and surface treatment affected site of debond location. (J Prosthet Dent 2007;98:199-207).

Influence of microwave disinfection on the dimensional stability of intact and relined acrylic resin denture bases

Microwave irradiation has been suggested as a method to disinfect denture bases. However, the effect of microwave heating on the dimensional stability of the relined denture bases is unknown. The purpose of this study was to evaluate the dimensional stability of intact and relined acrylic resin denture bases after microwave disinfection. A standard brass cast simulating an edentulous maxillary arch was machined and used to fabricate 2- and 4-mm-thick denture bases (n=200), which were processed with heat-polymerized acrylic resin (Lucitone 550). The 2-mm thick-specimens (n=160) were relined with 2 mm of autopolymerizing resin (Tokuso Rebase Fast, Ufi Gel Hard, Kooliner, or New Truliner). Distances between 5 removable pins on the standard brass cast were measured with a Nikon optical comparator, and the area (mm) formed by the distance between 5 pins was calculated and served as baseline. During fabrication, the pins were transferred to the intaglio surface of the specimens. Differences between the baseline area and those subsequently determined for the specimens were used to calculate the percent dimensional changes. The intact and relined denture bases were divided into 4 groups (n=10) and evaluated after: polymerization (control group P); 1 cycle of microwave disinfection (MW); daily microwave disinfection for 7 days (control group MW7); water storage for 7 days (WS7). Microwave irradiation was performed for 6 minutes at 650 W. Data were analyzed using 2-way ANOVA followed by Tukey's test (alpha=.05). Intact specimens and those relined with Kooliner and New Truliner showed increased shrinkage after 1 (P=.05, .018, and .001, respectively) and 7 (P <.001, .003, and <.001, respectively) cycles of microwave disinfection. With the exception of specimens relined with Kooliner, intact specimens showed greater shrinkage than the relined specimens after 7 cycles of microwave disinfection. Microwave disinfection produced increased shrinkage of intact specimens and those relined with New Truliner and Kooliner.

A modified one-step putty-wash impression technique

aClinical Instructor, Chang Gung Memorial Hospital, Chang Gung University College of Medicine. bProfessor, School of Dentistry, University of North Carolina. (J Prosthet Dent 2007;98:245-246) Although the literature demonstrates that optimum accuracy can be achieved with custom trays and stock trays,1-4 the putty-wash impression technique using an elastomeric impression material is a popular method. Two variations of the putty-wash impression technique are commonly used, the 2-step and 1-step.5 With the 2-step technique, a preliminary preoperative putty impression is made and, subsequently, “washed” with low viscosity material after tooth preparation. In terms of the 2-step puttywash impression technique, several methods are described for control of the bulk of the wash material,6-8 which is essential for fabricating accurate stone dies. With the 1-step procedure, low viscosity impression material is injected around the prepared tooth or teeth, and then the putty impression material is immediately placed intraorally and the materials polymerize simultaneously. Accuracy of impressions resulting from the 1-step putty-wash technique is controversial. Some authors found that there was no difference in accuracy between techniques,5,9-11 while others criticized several potential disadvantages with this approach. These disadvantages include lack of control of the bulk of wash material and the high risk of capturing portions of the prepared margin in putty material rather than lower viscosity material.12 Most putty viscosity materials have inadequate fine detail reproduction for this purpose. This article describes a modified 1-step putty-wash technique using vacuum-formed resin sheets as spacers to control the wash bulk and minimize the chance of unfavorable impression results. Using this technique, the limitations of using 1-step putty-wash impression can be eliminated.

Transferring the existing occlusal vertical dimension using a duplicate denture

aClinical Lecturer, Biologic and Materials Sciences, Division of Prosthodontics. bProfessor, Biologic and Materials Sciences, Division of Prosthodontics. (J Prosthet Dent 2007;98:68-69) 1 A, Three-mm-high healing abutments in place. B, Close tray impression copings. In patients for whom a fixed complete denture is required, different techniques are described to determine the occlusal vertical dimension such as rigid, stable, and accurate record bases1, gold cylinders,2,3 healing abutments, and others.4 This article describes a procedure using a duplicated complete denture to replicate the occlusal vertical dimension in a patient with implants. Several techniques were used to determine the accuracy of this procedure, including determining the occlusal vertical dimension after the fabrication of new record bases and occlusal rims and measurements using extraoral landmarks. After using these techniques, it was determined that the procedure presented produced an accurate occlusal vertical dimension for the patient presented.

Alternate functional impression technique for implant-retained overdentures

An overdenture impression must record the soft tissue supporting areas simultaneously with accurate positioning of the implant components. 1 Hussaini S. Wong T. One clinical visit for a multiple implant restoration master cast fabrication. J Prosthet Dent. 1997; 78: 550-553 Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar Three types of impression techniques have been described in the literature. A single-stage impression procedure is commonly used with either an open or closed tray technique. 2 De La Cruz J.E. Funkenbusch P.D. Ercoli C. Moss M.E. Graser G.N. Tallents R.H. Verification jig for implant-supported prostheses: a comparison of standard impressions with verification jigs made of different materials. J Prosthet Dent. 2002; 88: 329-336 Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar , 3 Ganddini M.R. Schejtman N. Ercoli C. Graser G.N. Prosthodontic application for implant carriers. J Prosthet Dent. 2004; 92: 399-402 Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar A double-impression technique for overdentures retained by only 2 implants has been suggested, using a zinc oxide eugenol (ZOE) impression paste and polyether impression material. 4 Mericske-Stern R.D. Taylor T.D. Belser U. Management of the edentulous patient. Clin Oral Implants Res. 2000; 11: 108-125 Crossref PubMed Google Scholar The third type of impression technique is a functional impression technique for implant-retained overdentures. 5 Uludag B. Sahin V. A functional impression technique for an implant-supported overdenture: a clinical report. J Oral Implantol. 2006; 32: 41-43 Crossref PubMed Scopus (3) Google Scholar Double and functional impression techniques are not considered for overdentures retained by more than 2 implants. 4 Mericske-Stern R.D. Taylor T.D. Belser U. Management of the edentulous patient. Clin Oral Implants Res. 2000; 11: 108-125 Crossref PubMed Google Scholar , 5 Uludag B. Sahin V. A functional impression technique for an implant-supported overdenture: a clinical report. J Oral Implantol. 2006; 32: 41-43 Crossref PubMed Scopus (3) Google Scholar , 6 Uludag B. Celik G. An alternative impression technique for implant-retained overdentures. J Prosthet Dent. 2006; 96: 377-378 Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar An implant-retained overdenture has characteristics resembling those of a complete denture, with a combination of tissue support and implant retention. 4 Mericske-Stern R.D. Taylor T.D. Belser U. Management of the edentulous patient. Clin Oral Implants Res. 2000; 11: 108-125 Crossref PubMed Google Scholar Thus, resilience difference between implant and mucosa should be considered for the impression of implant-tissue-retained overdentures. 6 Uludag B. Celik G. An alternative impression technique for implant-retained overdentures. J Prosthet Dent. 2006; 96: 377-378 Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar The functional impression technique records the mucosa in a functional state and simultaneously records the implant components in relation to the alveolar tissues. The primary advantage of this technique is to provide the accurate relation of the implant components and the supporting tissues. After insertion of the prosthesis, chair time decreases for postinsertion adjustments. 5 Uludag B. Sahin V. A functional impression technique for an implant-supported overdenture: a clinical report. J Oral Implantol. 2006; 32: 41-43 Crossref PubMed Scopus (3) Google Scholar However, the procedure is technique sensitive in recording the border relation with different impression materials, and it is more time consuming compared with the single-stage impression. This article describes an alternative functional impression technique to fabricate implant-retained maxillary overdenture with a bar design.

A digital video photographic technique for esthetic evaluation of anterior mandibular teeth

Improvement of dental and facial esthetics is an important indication for dental treatment. Photographic records aid in identifying esthetic disharmony, planning for esthetic correction, and establishing mutually compatible expectations of the dentist and patient. The conventional photograph of a smile is used ubiquitously for this purpose and effectively shows primarily the maxillary anterior teeth with surrounding facial structures. However, in the older patient, and especially in men, 1 Vig R.G. Brundo G.C. The kinetics of anterior tooth display. J Prosthet Dent. 1978; 39: 502-504 Abstract Full Text PDF PubMed Scopus (221) Google Scholar , 2 Tjan A.H. Miller G.D. Some esthetic factors in a smile. J Prosthet Dent. 1984; 51: 24-28 Abstract Full Text PDF PubMed Scopus (417) Google Scholar the mandibular anterior teeth receive greater exposure than those of the maxilla and are a zone of primary esthetic significance for these patients. Exposure of mandibular anterior teeth is generally evaluated with the lips in rest position 1 Vig R.G. Brundo G.C. The kinetics of anterior tooth display. J Prosthet Dent. 1978; 39: 502-504 Abstract Full Text PDF PubMed Scopus (221) Google Scholar ; however, their primary esthetic significance is more obvious during speech. Neither rest nor speech positions are shown by the standard smile photograph, which is therefore unsuitable for esthetic analysis of mandibular incisors. This article shows how the video function of a digital camera with readily available software can be used for effective esthetic analysis of the mandibular anterior teeth. The procedure is described for a specific digital camera but can be applied to other models with appropriate modifications.

Dental CAD/CAM systems: A 20-year success story

Dental CAD/CAM systems: A 20-year success story

Ball-springs require more repair than bar-clip implant-supported mandibular dentures

Article Title and Bibliographic Information A clinical trial of patient satisfaction and prosthodontic needs with ball and bar attachments for implant-retained complete overdentures: three-year results. MacEntee MI, Walton JN, Glick N. J Prosthet Dent 2005;93(1):28-37. Level of Evidence 1b Purpose/Question Which type of implant-supported mandibular denture was more satisfactory to patients, the bar-spring or the bar-clip attachment? In addition, which attachment required more maintenance? Source of Funding Government Type of Study/Design Stratified randomized controlled trial

Evaluating closest speaking space with Spanish terms

The closest speaking space (CSS) is the separation that exists between the incisal edges of the anterior teeth when a patient is unconsciously repeating the letter “s”. 1 The glossary of prosthodontic terms. J Prosthet Dent. 2005; 94: 24 Google Scholar , 2 Pound E. Let /S/ be your guide. J Prosthet Dent. 1977; 38: 482-489 Abstract Full Text PDF PubMed Scopus (71) Google Scholar The CSS method remains one of several used in the assessment of the proper occlusal vertical dimension (OVD) for prosthodontic patients. 3 Zarb G.A. Bolender C.L. Eckert S.E. Fenton A.H. Jacob R.F. Mericske-Stein R. Prosthodontic treatment for edentulous patients: complete dentures and implant-supported prostheses. 12th ed. Mosby, St. Louis2003: 379-387 Google Scholar , 4 Turner K.A. Missirlian D.M. Restoration of the extremely worn dentition. J Prosthet Dent. 1984; 52: 467-474 Abstract Full Text PDF PubMed Scopus (148) Google Scholar A time-efficient alternative is presented to overcome challenges that may be encountered when evaluating the CSS for patients whose primary language is Spanish (Table I).

Occlusion recording device for dental implant-supported restorations

The accurate transfer of the interocclusal relationship is essential for providing ideal occlusion. In unilateral distal extension situations, it may be difficult to hand-articulate the casts accurately. In these instances, record bases and occlusion rims are generally fabricated. For implant-supported restorations, the record base can be screwed directly on the implant during the interocclusal recording procedure at a separate appointment. 1 Hobo S. Ichida E. Garcia L.T. Osseointegration and occlusal rehabilitation. Quintessence, Chicago1989 Google Scholar Generally, the record base is attached to the gold cylinders, 1 Hobo S. Ichida E. Garcia L.T. Osseointegration and occlusal rehabilitation. Quintessence, Chicago1989 Google Scholar the healing abutments, 2 Rungcharassaeng K. Kan J.Y.K. Fabricating a stable record base for completely edentulous patients treated with osseointegrated implants using healing abutments. J Prosthet Dent. 1999; 81: 224-227 Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar or secured with the use of impression copings. 3 Savabi O. Nejatidanesh F. Interocclusal record for fixed implant-supported prosthesis. J Prosthet Dent. 2004; 92: 602-603 Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar The advantage of these methods is that there is no displacement of the implant during the interocclusal recording procedure, so an accurate record can be made. However, this procedure can be time consuming and requires additional visits to the dental office; furthermore, patients may experience discomfort from procedures such as the repeated removal of the healing abutments.

A method to minimize adjustment and enhance passivity of cast post-and-core restorations

The fitting of cast post-and-core restorations is critical to ensure good adaptation and passivity of fit. 1 Morgano S.M. Brackett S.E. Foundation restorations in fixed prosthodontics: current knowledge and future needs. J Prosthet Dent. 1999; 82: 643-657 Abstract Full Text Full Text PDF PubMed Scopus (144) Google Scholar , 2 Goerig A.C. Mueninghoff L.A. Management of the endodontically treated tooth. Part II: technique. J Prosthet Dent. 1983; 49: 491-497 Abstract Full Text PDF PubMed Scopus (30) Google Scholar , 3 Sorensen J.A. Engelman M.J. Effect of post adaptation on fracture resistance of endodontically treated teeth. J Prosthet Dent. 1990; 64: 419-424 Abstract Full Text PDF PubMed Scopus (135) Google Scholar If a passive fit is not achieved, wedging stresses may result in root fracture. 4 Morgano S.M. Milot P. Clinical success of cast metal posts and cores. J Prosthet Dent. 1993; 70: 11-16 Abstract Full Text PDF PubMed Scopus (115) Google Scholar However, in some situations, cast posts and cores do not fit precisely and, consequently, require adjustment, which may result in looseness of fit. 5 Holmes D.C. Diaz-Arnold A.M. Leary J.M. Influence of post dimension on stress distribution in dentin. J Prosthet Dent. 1996; 75: 140-147 Abstract Full Text PDF PubMed Scopus (184) Google Scholar , 6 Tjan A.H. Whang S.B. Resistance to root fracture of dowel channels with various thicknesses of buccal dentin walls. J Prosthet Dent. 1985; 53: 496-500 Abstract Full Text PDF PubMed Scopus (139) Google Scholar Indicating materials can be used to evaluate the fit of cast posts and cores. However, adjustment using carbide burs is not always exclusive to the binding areas and may result in overadjustment, thus influencing retention. 2 Goerig A.C. Mueninghoff L.A. Management of the endodontically treated tooth. Part II: technique. J Prosthet Dent. 1983; 49: 491-497 Abstract Full Text PDF PubMed Scopus (30) Google Scholar , 4 Morgano S.M. Milot P. Clinical success of cast metal posts and cores. J Prosthet Dent. 1993; 70: 11-16 Abstract Full Text PDF PubMed Scopus (115) Google Scholar

Patients with epilepsy may have an increased risk of tooth loss

Original Article Karolyhazy K, Kivovics P, Rajavaara P, Vainionpaa L, Rattya J, Knip M, et al. Prosthodontic status and recommended care of patients with epilepsy. J Prosthet Dent 2005;93(2):177-82. Level of Evidence 3b Purpose/Question The purpose of this study was to examine whether epilepsy is related to increased tooth loss. Source of Funding Information not available Type of Study/Design Case-control study

A technique for the manipulation of prosthetic screws intraorally

The insertion of an implant-supported prosthesis is easier when the prosthesis is cement-retained. 1 Misch C.E. Contemporary implant dentistry. 2nd ed. Mosby, St Louis1998 Google Scholar , 2 Hebel K.S. Gajjar R.C. Cement-retained versus screw-retained implant restorations: achieving optimal occlusion and esthetics in implant dentistry. J Prosthet Dent. 1997; 77: 28-35 Abstract Full Text Full Text PDF PubMed Scopus (374) Google Scholar This is due to the larger size and, consequently, easier manipulation of the prosthetic implant components needed to complete a cement-retained restoration (abutment and abutment screw), compared to the size of the prosthetic screws used in screw-retained restorations. Hand manipulation of the prosthetic screws in screw-retained restorations can be difficult intraorally, especially in posterior areas, because of their small head size. Screws are not easily held by the screwdriver tip. A simple technique to manage prosthetic screws intraorally during the insertion of screw-retained prostheses is described. The sticky consistency of the gel/petroleum jelly allows easier clinical manipulation of the prosthetic screw with the screwdriver.

A method to reduce tooth movement of complete dentures during microwave irradiation processing

Harmony of the stomathognatic system is an aim of oral rehabilitation. Variations in occlusion caused by processing changes may result in traumatic occlusion, nonuniform distribution of occlusal stresses to underlying tissues, and changes in oral function, comfort and masticatory efficiency. 1 Ruffino A.R. Improved occlusal equilibration of complete dentures by augmenting occlusal anatomy of acrylic resin denture teeth. J Prosthet Dent. 1984; 52: 300-302 Abstract Full Text PDF PubMed Scopus (7) Google Scholar Occlusal harmony is important in complete denture control and accuracy of fit of the prosthesis to the underlying tissues and peripheral extensions. 2 Dubojska A.M. White G.E. Pasiek S. The importance of occlusal balance in the control of complete dentures. Quintessence Int. 1998; 29: 389-394 PubMed Google Scholar Occlusal interferences can occur due to errors introduced in the clinical or laboratory procedures during the fabrication of the prothesis. 3 Zakhari K.N. Relation of investing medium to occlusal changes and vertical opening during denture construction. J Prosthet Dent. 1976; 36: 501-509 Abstract Full Text PDF PubMed Scopus (11) Google Scholar Dimensional changes and distortion are inherent to acrylic resin and dental stone and can cause tooth movement and, consequently, alterations in the vertical dimension of occlusion and occlusal contacts. 4 Anusavice K.J. Philips' science of dental materials. 11th ed. Elsevier, St. Louis2004 Google Scholar

A simple technique for marking the ala-tragal line

During complete denture fabrication, it is often necessary to use facial landmarks to assist in the proper contouring of the occlusion rims. One of the parameters in determining the maxillomandibular relationship is identification of the occlusal plane. This may be achieved by using an occlusal plane guide, which, after adequate and proper contouring of the maxillary occlusion rim, is made parallel to the Camper's plane 1 The glossary of prosthodontic terms. J Prosthet Dent. 1999; 81: 56-57 Google Scholar (ala-tragal line). Rough visualization of the ala-tragal line is a method of determining parallelism of the wax occlusion rim with the Camper's plane, but this may be difficult to determine when holding a ruler with one hand and attempting to keep it stationary. A simple, quick, and predictable method of visualizing the Camper's plane is proposed in this article.

Fabrication of removable partial denture remount casts prior to delivery

Occlusal equilibration is an important step in the insertion of a removable prosthesis. 1 Kratochvil F.J. Partial removable prosthodontics. WB Saunders, Philadelphia1988 Google Scholar Both intraoral and extraoral equilibration techniques may be used, depending on the type of support for the removable partial denture (RPD) and the type of occlusion. Although intraoral refinement in some situations can be accomplished to an acceptable degree of accuracy, extraoral equilibration on an articulator is recommended and desirable in many instances. 1 Kratochvil F.J. Partial removable prosthodontics. WB Saunders, Philadelphia1988 Google Scholar , 2 Johnson D.L. Stratton R.J. Fundamentals of removable prosthodontics. Quintessence, Chicago1980 Google Scholar , 3 Lauciello F.R. Technique for remounting removable partial dentures opposing maxillary complete dentures. J Prosthet Dent. 1981; 45: 336-340 Abstract Full Text PDF PubMed Scopus (11) Google Scholar Unfortunately, extraoral equilibration may be time-consuming or omitted if remount cast fabrication is done at the insertion appointment. To incorporate the advantages of extraoral equilibration with reasonable chair time during insertion, a method for fabricating an RPD remount cast during the wax trial insertion appointment is described.

A method of direct transfer printing for personal identifications on sports mouth guards

Mouth guards were developed to prevent sport-related oral injuries. In organized team sports, many players use similar mouth guards; therefore, a method to identify personal mouth guards is needed. Several techniques for identifying mouth guards have been described. 1 Yonehata Y. Maeda Y. Method of placing personal identification on acetate mouth guards. J Prosthet Dent. 1999; 82: 494 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar , 2 Reeson M.G. Jepson N.J. Simple procedure for mouth guard identification for school-aged children. J Prosthet Dent. 2000; 83: 688-689 PubMed Scopus (2) Google Scholar One method is to carve the individual's name or number on the mouth guard. 1 Yonehata Y. Maeda Y. Method of placing personal identification on acetate mouth guards. J Prosthet Dent. 1999; 82: 494 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar Another is to put a label with an individual's name between layers of mouth guard sheets. 2 Reeson M.G. Jepson N.J. Simple procedure for mouth guard identification for school-aged children. J Prosthet Dent. 2000; 83: 688-689 PubMed Scopus (2) Google Scholar However, the second method can only be used for mouth guards made from laminated materials and requires additional laboratory time and expense. This article describes a method of direct transfer printing for the personal identification of mouth guards. This method is simple and may be used for all types of custom-made mouth guards. The authors have observed that the transfer lasts at least 1 month.