The accuracy of clinician evaluation of interproximal contacts using different methods.

STATEMENT OF PROBLEM: Complete seating of a single crown may not be possible if the interproximal contacts are excessively tight. Incomplete seating can lead to open margins, inflammation of the gingival tissue, and recurrent dental caries. PURPOSE: The purpose of this in vitro study was to determine the accuracy of 3 different methods of evaluating interproximal contacts when seating a single crown. MATERIAL AND METHODS: Thirty-five restorative dentists practicing in the Lincoln, Nebraska, area were polled to determine the methods they used most commonly to evaluate the interproximal contacts of crowns. These dentists then evaluated the interproximal contacts of 9 anatomic contour zirconia crowns on a dentoform using 3 different methods: floss and explorer, occlusal articulating film (AccuFilm), and shim stock. Crown fit was evaluated using 1 method at a time. Each crown was recorded as either "accept" or "reject" according to the individual clinician. All data were analyzed with the McNemar test (α=.05). RESULTS: Of the 35 restorative dentists polled, 34 identified floss and explorer, 9 identified occlusal articulating film, 3 identified shim stock, and 3 identified an occlusal spray as their method of evaluating interproximal contacts. These methods were used either alone or in conjunction with other methods. Evaluation of the in vitro data revealed that shim stock and occlusal articulating film were significantly more accurate than floss and explorer for assessing interproximal contacts in poorly fitting crowns (P<.001). For well-fitting crowns, shim stock and occlusal articulating film were significantly more accurate than floss and explorer (P<.001). CONCLUSIONS: This study showed that the floss and explorer method was the least accurate means of evaluating the interproximal fit of crowns. Shim stock provided the most accurate method of evaluating interproximal contact, and occlusal articulating film provided both high accuracy and a visible mark to facilitate adjustment.

Management of a Damaged Implant for Retention of an Overdenture Prosthesis and Fixed Single Crown: Clinical Reports.

This article demonstrates a method to salvage an implant that has been damaged or is no longer usable because of a fractured screw that cannot be removed. In the first situation the patient had a Locator abutment that fractured during torqueing of the abutment. Despite the attempt to remove the fractured screw, it was not retrievable, and the internal threads of the implant were damaged in the attempt to remove the screw. Rather than removing the implant or covering it and sleeping the implant, a custom cast post was used to restore the implant to function. A second example describes a patient with a fixed implant crown. The implant was damaged during attempts to remove the fractured screw. A custom post was fabricated and cemented, and a new crown was fabricated.

Cast erosion from the cleaning of debris after the use of a cast trimmer.

STATEMENT OF PROBLEM: Whether using tap water to rinse off debris will make a clinical difference to the surface detail of a gypsum cast is unknown. In addition, how best to remove debris from the cast is unknown. PURPOSE: The purpose of this in vitro study was to evaluate the efficiency of different methods of cleaning a gypsum cast after trimming and the effect of short-term exposure to tap water on the surface quality of the cast. MATERIAL AND METHODS: A die fitting American National Standards Institute/American Dental Association specification 25 (International Standards Organization specification 6873) for dental gypsum products was embedded in a Dentoform with the machined lines positioned at the same level as the occlusal surface of the posterior teeth. A flat plate was used to ensure that the plane of occlusion for the die was at the same position as the posterior teeth. Forty polyvinyl siloxane impressions of the Dentoform were made and poured with vacuum-mixed improved Type IV dental stone. Each cast was inspected for the accurate reproduction of the lines. The base of the 2-stage pour was trimmed with a cast trimmer with water, and surface debris was removed by rinsing by hand under tap water for 10 seconds, by brushing the cast with a soft toothbrush for 10 seconds, or by resoaking the cast and using a soft camel hair brush in slurry water for 10 seconds. The amount of debris was evaluated on a scale of 1 to 4, and the quality of the 20-µm line was evaluated on a scale of 1 to 4 under ×15 magnification. The nonparametric Kruskal-Wallis ranks test was used to identify significant differences among the different cleaning methods (α=.05). RESULTS: Results of the Kruskal-Wallis and Kruskal-Wallis Z-value tests demonstrated that all cleaning methods produced cleaner casts than were observed for uncleansed controls (P<.001), but no differences in debris removal were found among the different cleaning methods (.065≤P≤.901). The ability to see the quality of a 20-µm line (P=.974) was not statistically different among the groups. CONCLUSIONS: Rinsing the cast under flowing tap water and brushing, or hand washing under flowing tap water, or using a soft camel hair brush in slurry water for 10 seconds had no noticeable effects on the quality of a 20-µm line, and all 3 methods resulted in a clean cast.

Fabrication of a Feeding Obturator for Infants.

Large clefts in the lip and palate are common congenital anomalies. If the cleft palate is large enough, conventional feeding techniques may not provide proper nutrition for the infant. Feeding obturators will aid in the ability of the infant to attain suction and help the infant to feed adequately. It is necessary for the infant to have sustained weight gain prior to surgery to correct the cleft lip and/or palate. Fabrication of an infant feeding obturator is a simple technique using materials found in every dental office. An impression is made using modeling plastic impression compound. This impression is relined using irreversible hydrocolloid, and the resulting cast is used to enable a vacuum-formed obturator to be fabricated. The vacuum-formed obturator is smoothed and adjusted in the infant's mouth to ensure closure of the palate but allows pace posteriorly to allow normal breathing. The resulting obturator is well retained in the infant's mouth, allowing feeding.

A quick esthetic remount cast for all-ceramic restorations.

A technique is presented for the expedited fabrication of a remount cast for the alteration of all-ceramic crowns and fixed partial dentures. The remount cast allows the laboratory technician to know the precise location of the gingival tissues and allows modification of all-ceramic restorations.

A provisional fixed partial denture for an implant prosthesis.

This article presents a technique for fabricating an esthetic provisional restoration on multiple implants. Fabricating a provisional restoration allows the dentist to make a replica of the desired restoration. The incisal edge can be placed for esthetics and function in the new provisional restoration, allowing patients to evaluate comfort and test their ability to speak with the contour of the provisional restoration. Patients can evaluate both the ease of cleaning the restoration and how tissue esthetics can be duplicated to their satisfaction. By adding acrylic resin to or removing it from the provisional, the dentist can easily change the restoration until the patient is satisfied with the esthetic and functional result. This technique will allow the dentist to fabricate the provisional prosthesis quickly, while the patient is in the chair.

The quality of post and cores made using a reduce-time casting technique.

OBJECTIVES: This study investigated the castability or casting completeness, surface roughness and dimensional accuracy of castings produced using a technique that requires as little as 24 minutes from the time of investment. METHODS AND MATERIALS: A total of 225 gold castings (45 per group) were fabricated using two standard and three accelerated casting protocols. For each casting protocol, 15 castings were made from a rectangular, diamond-shaped mesh Duralay pattern to be used for castability evaluation; 15 castings were made from a flat, square pattern for measurement of surface roughness, and 15 castings were made from a tapered Duralay dowel to evaluate dimensional accuracy. Castings made with Fast Fire 15 and Ceramigold investment with shortened burnout times were compared to those made using Beauty Cast and Fast Fire 15 investment following the manufacturer's recommendations. Castability was evaluated by counting the number of diamonds cast in a rectangular mesh. A profilometer was used to measure surface roughness. To check dimensional accuracy, the casting was replaced in the original mold and a traveling microscope was used to measure the size difference at 32x magnification. RESULTS: There were no statistically significant differences in castability and dimensional accuracy throughout all groups (p > .05). There was a statistically significant difference in the surface roughness of casts formed by Ceramigold compared to the other groups (p < .001). CONCLUSION: The short casting time using Fast Fire 15 can produce post and core castings that are of a quality acceptable for clinical use.

Making multiple predictable single-unit provisional restorations using an indirect technique.

This article describes a method to fabricate single provisional restorations for multiple preparations using an indirect technique. Provisional restorations need to mimic the definitive restoration as closely as clinically possible. When multiple adjacent provisional restorations are fabricated, the ability to make each separately, with its own path of insertion and contour, aids in providing a predictable final result for the patient. Individual provisional restorations will also allow the patient to maintain better hygiene.

A descriptive 18-year retrospective review of subperiosteal implants for patients with severely atrophied edentulous mandibles.

STATEMENT OF PROBLEM: Fabricating dentures for the patient with severe mandibular atrophy can be a challenge for both the dentist and patient. Subperiosteal implants with a mandibular overdenture may be a solution for the atrophic mandible. PURPOSE: The purpose of this retrospective study was to review the survival of mandibular subperiosteal implants placed at the University of Missouri Kansas City (UMKC) School of Dentistry Graduate Prosthodontics program between 1982 and 2000. MATERIAL AND METHODS: Forty subperiosteal implants were placed in atrophic mandibles of 40 patients (33 women, 7 men) between 1982 and 2000. The age range of the patients was 47 to 80 years of age at time of placement (mean=62 years). Each patient was reviewed clinically by an author (DJM). Manual depression and lifting of the framework were used to evaluate the stability of the implant. Additionally, the implants were observed for any movement. Each patient was questioned for pain or discomfort. Each patient was examined for observable inflammation and intraoral exposure of the framework and questioned as to whether the implant had satisfied the patient and met the patient's expectations. RESULTS: Thirty-nine of the 40 original patients were recalled in 2000. One patient had died. Fourteen patients had implants for over 10 years, 12 patients had implants between 5 and 10 years, and 12 patients had implants for less than 5 years (mean time of implant service=8 years). Thirty-eight patients had the implant in place with no sign of inflammation or mobility, 1 patient with diabetes had inflammation around one of the struts. All patients were wearing their prostheses, and there was no sign of exposed implant framework for any patient. All patients reported a high level of satisfaction with the implant. CONCLUSIONS: Within the limitations of this study, the mandibular implants placed at UMKC were still functioning, and all patients denied any discomfort or pain from the prostheses. Patients reported they were comfortable and able to function with the implant-supported prosthesis.