Crown Coverage Research Articles

Management of the primary dentition in vitamin D-resistant rickets

Vitamin D-resistant rickets (familial hypophosphatemia) is a systemic disease secondary to defective renal-tubular reabsorption of phosphate. The major oral manifestations are spontaneous abscesses in a caries-free dentition. Pulpotomies or extractions were frequently described in the dental literature as the therapies of choice. This article presents a new prophylactic approach utilizing zinc oxide—eugenol pulpectomies and full crown coverage in an attempt to retain the primary dentition and prevent abscess formation.

A comparative evaluation of three post and core techniques

An in vitro study was performed evaluating three post and core techniques with and without full crown coverage on extracted mandibular molar teeth. The materials evaluated were amalgam, composite resin, and stainless steel posts, and a combination of cast-gold and stainless steel posts. The results indicate that the method of post and core technique may not be as significant as the placement of full coverage cast-gold crown restorations with sound design and placement of margins beyond the buildup restoration.

Simplified copper tube impressions for full crown coverage

A simplified impression technique using copper tubes has been described. Gingival retraction is eliminated, and an accurate selection and fitting of the tube can be carried out with a minimum of time.

Community Structure and Stability in the Giant Sequoia Groves of the Sierra Nevada, California

The vegetation of the giant sequoia groves is dominated by Abies concolor, with Pinus lambertiana as a characteristic associate. Sequoiadendron giganteum is of small importance in relative density, but includes the majority of basal area of canopy species within the groves. Despite its great basal area, crown coverage of Sequoiadendron seldom exceeds 5%. Libocedrus decurrens is an important associate in lower-elevation groves, particularly following fire disturbance. Groundcover vegetation is extremely variable. Present grove boundaries appear to be remarkably stable. There is no evidence of any change in grove boundaries during the last 500 years or longer. A great majority of groves are undergoing a gradual decrease in density of giant sequoias due to low levels of regeneration. This decline in density began long before the influence of Western civilization on the groves.

Reconstruction of anterior teeth with an extreme vertical and horizontal overlap

A procedure that corrects undesirable appearance and function of malposed and unsightly upper anterior teeth has been described. The roots of the teeth rather than the crowns are prepared and used for full crown coverage. The tooth roots are not sacrificed, and they are used to support restorations with an improved appearance.

Periodontal and dental health

It seems obvious that dentists must approach the problem of full coverage with extreme caution, reserving that type of restoration for situations in which nothing else will serve the purpose. A return to the use of pinledge and three-quarter veneer crowns seems to be indicated to preserve the integrity of the periodontal tissues, to reduce the risk to pulps, and to increase averages of success in restorative dental procedures and mouth rehabilitation. Proper operative and prosthetic dental service is such an integral and inseparable part of periodontal health that dentists cannot provide one without the other. An effort has been made to present a concept of periodontal health and its relation to total oral health. There cannot be a healthy mouth with a diseased periodontium. It is basic that the periodontal tissues must be treated first to prepare a healthy foundation for the operative and prosthetic treatment to follow. Heroic attempts to retain teeth which are periodontally diseased to a stage where they should be extracted must be avoided. Such teeth should not be incorporated in splinted fixed partial dentures. Splinting a hopelessly loose tooth will not tighten it; it will jeopardize the healthy teeth to which it has been splinted. The indiscriminate use of full crown coverage should be discouraged. Experience with full coverage has taught that a return to the use of pinledge and three-quarter veneer crowns is indicated.