Daniel Galindo

Long-term reinforced fixed provisional restorations

Extensive prosthodontic treatment often requires fabrication of long-term provisional restorations. Numerous materials and techniques have been described for prolonged insertion of interim restorations. This article describes a procedure for fabrication of long-term reinforced heat-processed provisional restorations based on a diagnostic wax-up. Reinforced heat-processed provisional restorations reduced flexure, which minimizes progressive loss of cement and diminished the possibility of recurrent decay. Occlusal stability and vertical dimension were maintained because of greater wear resistance. Occlusion, tooth contours, and pontic design developed in the provisional restoration were duplicated in the definitive restoration. The use of a matrix from a diagnostic wax-up facilitated fabrication of the prosthesis, and made the procedure less time-consuming and more predictable.

Tooth Preparation: A Study on the Effect of Different Variables and a Comparison Between Conventional and Channeled Diamond Burs

PURPOSE The purpose of this study was to evaluate the different variables involved in tooth cutting to characterize intrapulpal temperature generation, cutting efficiency, and bur durability when using conventional and channeled diamond burs. MATERIALS AND METHODS Forty premolars and 60 molars were selected for the study. Four diamond burs were paired according to grit size: 125-microm grit: Brasseler Coarse (Control 1) and TDA System (Test 1) burs; and 180-microm grit: Brasseler CRF (Control 2) and NTI Turbo Diamond (Test 2) burs. Each bur was used twice when cutting the premolar teeth, whereas it was used for 60 cuts when cutting the molar teeth. The data were analyzed to compare the correlation of bur design, grit and wear, amount of pressure, advancement rate, revolutions per minute, cutting time and rate, and proximity to the pulp chamber with intrapulpal temperature generation, cutting efficiency, and bur longevity. The mean values of test and control burs in each group were compared using an ANOVA (p < 0.05 for significant differences) for temperature generation and an ANOVA and the Tukey multiple range test (p< or = 0.05) for cutting efficiency and bur longevity. RESULTS No significant difference was found in intrapulpal temperature generation while cutting premolar and molar teeth with conventional and channeled diamond burs. In both groups, the mean temperature recorded during and after the cutting procedure was lower than the baseline temperature. For premolar teeth, no significant difference was established for control and test burs for the load required to cut into the tooth and the cutting rate. However, both test burs showed significantly fewer revolutions per minute when compared to their control counterparts. For the molar teeth, the Brasseler CRF bur required a significantly lower cutting load when compared to the NTI bur, whereas no difference was noted between the other pair of burs. The cutting rate was significantly higher for both control burs, whereas revolutions per minute (rpm) were greater for control coarser burs only. Overall, channeled burs showed a significantly lower cutting efficiency when compared to conventionally designed burs. CONCLUSION Within the limitations of this study, channeled burs showed no significant advantage over conventional diamond burs when evaluating temperature generation and bur durability. Moreover, the cutting efficiency of conventional burs was greater than that of channeled burs.

Implant position record and implant position cast: minimizing errors, procedures and patient visits in the fabrication of the milled-bar prosthesis.

This article describes a new rationale and method involved in the fabrication of a patient detachable prosthesis supported by a milled bar. This simple procedure improves prosthesis retention. The overdenture is processed directly over a milled bar, which provides an intimate relation between the bar and the acrylic resin denture base to create resistance against rotational and lateral forces acting on the prosthesis. Incorporating simple and predictable attachments, with low maintenance needs, controls resistance to dislodgment along the path of insertion of the prosthesis. The concepts used in the fabrication of the milled bar include an implant position record (IPR) and an implant position cast (IPC) to reduce the need for time-consuming procedures, such as sectioning the cast bar and soldering it to make it fit the abutments. This procedure also reduces the number of patient visits required of the completion of the prosthesis.

Face-bow record without a third point of reference: Theoretical considerations and an alternative technique

Accurate mounting of dental casts is achieved by transferring the tridimensional spatial relationship of the maxillary arch to an articulator. A face-bow is used to transfer this relationship to the articulator, usually by relating the face-bow to a plane of reference. The most common reference plane is the Frankfort plane, which has been assumed to be horizontal when the patient is in the natural head position. The axis-orbitale plane has also been considered horizontal and used as reference. However, it has been shown that both planes are not horizontal, and mounting a maxillary cast according to these planes can result in an inaccurate mounting. This article describes an alternative procedure for face-bow transfer without a plane of reference, and uses the angular relationship between the occlusal plane and the condylar path to mount the maxillary cast on the articulator. The elimination of a reference plane, to which relate the functional determinants of occlusion, avoids an additional source of error during the mounting procedure.

Comparison of the load at failure of soldered and nonsoldered porcelain-fused-to-metal crowns.

STATEMENT OF PROBLEM The application of solder material to metal frameworks could affect the porcelain-to-metal failure load and possibly compromise the longevity of porcelain-fused-to-metal crowns. PURPOSE This in vitro study assessed the influence of solder on the porcelain failure load between metal and porcelain, using crown-shaped specimens. MATERIAL AND METHODS Forty standardized crown patterns were fabricated on a metal die and cast with noble alloy (Protocol). The specimens were divided into test (soldered, n=20) and control (nonsoldered, n=20) groups. A 2-mm-diameter perforation was produced on the buccal surface of the test specimens, 1.5 mm apical to the junction between occlusal and buccal surfaces. The perforation was repaired with high-fusing white ceramic solder material. All castings were finished with aluminum oxide stones and airborne-particle abraded with 50-microm aluminum oxide at 75 psi of pressure. Two layers each of opaque and dentin porcelain were applied on all specimens. All crowns were subjected to a vertical compressive load with a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. The loading apparatus of the device contacted the buccal cusp only. In both control and test groups, 10 crowns were loaded with a stainless steel pin (phase I) whereas the remaining 10 in each group were loaded with a carbon steel pin (phase II). Means of loads at failure were recorded in each group for each pin type and compared (soldered vs nonsoldered) by use of a t test (alpha=.05). RESULTS Mean failure load for nonsoldered crowns was 349 +/- 63 kgf in phase I and 228 +/- 49 kgf in phase II. Soldered crowns showed a significantly lower failure load (265 +/- 82 kgf [phase I; P<.02] and 154 +/- 108 kgf [phase II; P<.04]) and a greater standard deviation. CONCLUSION Soldered metal-porcelain crown specimens demonstrated a significantly lower load at failure. Within the limits of this study, it was concluded that solder material might negatively affect porcelain-metal crowns.

Immediate Loading of Dental Implants in the Esthetic Region Using Computer‐Guided Implant Treatment Software and Stereolithographic Models for a Patient with Eating Disorders

This manuscript describes the reconstruction of a maxillary anterior segment using immediate implant placement and immediate implant loading techniques, aided by computer-guided implant treatment software and stereolithographic models and surgical templates, in a patient with a history of eating disorder. Her medical and dental histories did not make her a candidate for the use of conventional 2-stage implant surgery and restorative procedures along with an interim removable prosthesis.

Procedure to prevent cast breakage during separation from elastomeric impressions

This article describes a quick and simple procedure for removing dental stone casts from elastomeric impressions. Frequently, dental stone casts break at the time of separation because of the rigidity of the impression material. The materials used in this technique are inexpensive and easy to use. When this method is properly used, it simplifies the removal of the cast from the impression, decreasing the chance of fracture of the cast.