F. Michael Gardner

A survey of crown and fixed partial denture failures: Length of service and reasons for replacement

The mean length of service of all restorations observed in this study was 8.3 years. Caries was the most common cause of failure, affecting 22.0% of the units failed and leading to the necessity for replacement of 24.3% of the units observed. Mechanical problems accounted for 69.5% of the failed units as opposed to 28.5% for oral disease. Resin veneer metal crowns provided the longest service of all crown types observed (13.9 years) and failed most frequently because of worn or lost veneers. The complete veneer metal crown had a life span of 6.1 years and was most likely to fail because of caries or defective margins. Ceramic-metal crowns also showed a relatively short period of service at 6.5 years, needing replacement primarily because of porcelain failure or poor esthetics. The resin-veneer metal crown also provided the longest service as a retainer, with a mean length of service of 14.7 years. This was closely followed by the partial veneer retainer (14.3 years), while the ceramic-metal retainer had the shortest life span (6.3 years). No apparent relationship was found between the span of prosthesis and its length of service. The six-unit canine-to-canine fixed partial denture exhibited the greatest longevity of the prostheses studied (10.4 years), while the two-unit cantilever fixed partial denture provided a mean of only 3.7 years of service before replacement was required.

Margins of complete crowns--literature review.

Abstract The margin is one of the components of the cast restoration most susceptible to failure, both biologically and mechanically. Most of the investigative proof shows that supragingival margins are kinder to the gingiva than are subgingival margins. However, practicality dictates that supragingival margins are not always usable. There is some indication that quality of the margin may be of as much importance to gingival health as location. Research on the configuration of margins seems to agree with the majority of authors writing technical articles. Most agree that feather edge or knife edge margins are not always the most acceptable. Apparently bulky margins with subtle internal line angles are best. Bevels are recommended where esthetics allows due to their slip-joint effect affording closer adaptation. Most cemented castings do not fit nearly as well as theoretical tests of cement film thicknesses would lead us to believe. Venting or providing space for cement through electromilling, aqua regia etching, or die spacing markedly improves the seating and, therefore, the marginal fit of castings. This seems to be a more useful approach to close fitting margins than burnishing and finishing margins, particularly for subgingival margins. Most of the commonly used fixed partial denture alloys, both precious and non-precious, are too hard to be burnished effectively. As long as fixed prosthodontics must rely on the cemented casting, the search for more knowledge about an innocuous, esthetic, indestructible margin must continue.

Using removable gingival facades with fixed partial dentures.

Abstract A technique for restoring an anterior edentulous space with accompanying severe alveolar bone loss has been presented. This technique, which combines fixed and removable restorations to achieve an acceptable esthetic result, is relatively simple, inexpensive, and hygienic. The facade is also applicable to restore esthetics to severely lengthened anterior clinical crowns, which through periodontal surgery have a great deal of gingival tissue missing.

A comparison of healing and pain following excision of inflammatory papillary hyperplasia with electrosurgery and blade-loop knives in human patients

Twenty human patients participated in a study designed to compare electrosurgery with blade-loop knives for the excision of inflammatory papillary hyperplasia in a split-mouth study. Questionnaires were used to assess pain and patient preference during a 2-week postoperative period, and photographs were made to chronicle the healing process. Healing occurred at approximately the same rate following each procedure. The majority of subjects did not perceive a difference in discomfort with either technique on the day of surgery or at any time during follow-up. Of those who did have a preference, a significant majority favored electrosurgery on the day of treatment. This preference became statistically insignificant on the second postoperative day and beyond.

Composite dowels and cores: Effect of moisture on the fit of cast restorations

A study was undertaken to evaluate the effect of interim restorations on the dimensional stability of composite post and core buildups subjected to moisture during the fabrication of cast restorations. Dimensional change associated with composite dowel and core buildups did not significantly alter the fit of cast restorations compared with natural teeth under the same conditions. The use of composite dowels and cores for the restoration of endodontically treated teeth is not contraindicated because of potential dimensional instability of the resin when exposed to moisture. Well-fitting interim restorations for either natural teeth or composite dowel and core buildups improved the fit of cast restorations 23% to 36%.

Artifacts in recording immediate mandibular translation: A laboratory investigation ☆ ☆☆ ★ ★★ ♢ ♢♢ ♦

STATEMENT OF PROBLEM Even though immediate mandibular translation has been extensively studied and analyzed, and its clinical significance emphasized, there is controversy as to whether it actually exists or whether it is just an artifact of the pantograph. PURPOSE The aim of this study was to determine whether what appears to be pantographic evidence of immediate mandibular translation can actually be an artifact and, if so, to find a method to avoid it. MATERIAL AND METHODS The first part of this article explains geometrically with computer vector graphics how pure rotation can produce a pantographic tracing on the horizontal plate that is identical to what would be seen for immediate mandibular translation. The second part of the article presents a technique that uses a modified pantograph that eliminates the rotational artifact and thus permits proper interpretation of true immediate mandibular translation. RESULTS This study shows that pure rotation about the sagittal axis mimics immediate mandibular translation on a pantographic tracing when the plates are inferior to the transverse horizontal axis, produces scribings in an opposite direction for plates in a superior position, and produces no scribing when the plates are level with it. By modifying the pantograph so the tip of the scribing pin of the horizontal plate is level with the transverse horizontal axis, true immediate mandibular translation can most easily be differentiated from rotational artifact. CONCLUSIONS AND CLINICAL SIGNIFICANCE Rotation can cause artifacts that mimic immediate mandibular translation. A technique to avoid this problem is presented. This technique provides the foundation for a valid evaluation of patients to determine whether true immediate mandibular translation exists and whether it is clinically important.

Adjustment of cast clasps for direct retention

A technique for the adjustment of half-round cast clasp arms for direct retention will be described. This technique permits a bend in the clasp that is in harmony with the metallic grain structure; however, the technique requires that the retentive tooth structure be recontoured or “dimpled.” Therefore, the anatomy of the tooth must first be evaluated. The surface to be recontoured should approach parallelism to the path of insertion. If this requirement is not met, the adjustment will be ineffective. If the surface for retention can be recontoured, the following procedure should be followed.

Contouring and staining ceramic-metal restorations in the mouth

Summary An office technique has been described whereby the dentist, using minimal time and money, may produce an individualized and esthetic result with ceramic-metal restorations. This result can only be obtained by the dentist working with the patient; it cannot be obtained by the laboratory technician working with only models and casts.

The effectiveness of 5-iodo-2′-deoxyuridine (IDU) on herpes simplex labialis

Abstract IDU does not shorten the natural course of recurrent HSL. It appears that recurrent herpes virus infections of the lip, as well as the eye, are at least partially resistant to IDU therapy.