Maury Massler

Alveolar ridge resorption following tooth extraction

F ollowing tooth extraction, the fundic part of the bony socket fills in with connective tissue and bone, while the alveolar crest resorbs. After the wound heals and is covered with epithelium, the edentulous ridge remains.l-lo An important question is whether the center of the resulting residual ridge lies over the center of the original dentulous ridge or has shifted towards the original lingual or labial plate. This question is important to the prosthodontist who asks whether the artificial tooth should be placed over the center of the edentulous ridge or whether the artificial tooth should be placed more to the buccal or the lingual side of it in order to occupy more accurately the position of the natural tooth. On the basis of observations of dry skull specimens, Cryer’l stated that the edentulous lower jaw lies external to and is wider than the upper jaw after all teeth have been extracted. Rogers and Applebaum12 concluded from measurements made in cadavers with dentulous and edentulous jaws that in the maxillae the vertical height of the ridges had decreased, and the crest of the edentulous ridge had shifted palatally after tooth extraction. They felt that in the mandible the most extensive resorption of alveolar bone occurred on the superior surface of the ridge and on the lingual surface of at least the posterior part of the ridge. Thus they suggested that resorption of the labial plate in the maxillae results in a loss of edentulous arch length and width, while, in the mandible, resorption of the lingual plate increases the mandibular arch length and width so that the edentulous maxillary arch comes to lie within the edentulous mandibular arch. Tylman and Tylman13 wrote that, in the maxillae, the labial and buccal alveolar plates resorb much faster than the palatal plates, while, in the mandible, the amounts of bone resorbed at the lingual and labial plates are approximately the same. Swenson14 stated that after tooth extraction the alveolar process of the

Ridge Remodeling after Tooth Extraction in Rats

Several histologic and radiographic studies have been made on the healing of wounds after the extraction of teeth in man,1-5 monkeys 6-9 dogs,1019 and rats.20-23 These histologic studies have shown that extraction-wound repair in animals was basically similar in sequence but more rapid than in human beings. The sequence in the healing of an alveolar socket after tooth extraction was: ( 1 ) bloodclot formation; (2) replacement of the blood clot by granulation tissue; (3) substitution of granulation tissue by connective tissue; (4) complete epithelization; (5) appearance of osteoid tissue at the base of the socket; and (6) filling in of the apical two thirds of the socket by trabecular bone. Although the reparative process within the extraction wound has been described in some detail, the remodeling process at the alveolar crest and therefore the pattern of edentulous ridge formation has not been similarly studied. Only the macroscopic appearance of the edentulous ridge has been described in man. Cryer 24 stated that the lower jaw was external to and wider than the upper jaw after all teeth had been extracted. Rogers and Applebaum25 have concluded, from measurements made in cadavers with dentulous and edentulous jaws, that in the maxilla the vertical height of the ridges had decreased and the crest of the edentulous ridge had shifted lingually after tooth extraction. They felt that the most extensive resorption of alveolar bone in the mandible occurred in the superior surface of the ridge and on the lingual surface of at least the posterior part of the ridge. This accounted for the relative smallness of the upper edentulous arch when compared with the edentulous lower ridge. Both important studies are inconclusive because of the many variables encountered

The Appositional Life Span of the Enamel and Dentin-Forming Cells

There are in general 2 types of growth; a) multiplicative growth as a result of cell-division, and b) appositional growth or growth by addition as a result of cellular secretion (Huxley, 1932). In either case, growth is the result of cellular activity. The analysis of such cellular activity offers a fertile field for investigations in the cellular dynamics of growth. Growth Potential of a Cell. The growth potential of a cell may be defined as the amount of growth work which a given cell is capable of performing. The growth potential can be measured by the result of that cells activity (the total number of cells or amount of tissue matrix). The amount of growth work is in turn the product of the rate of cellular activity (division or secretion) and the time during which the cell was active (its functional life span).

Influence of cavity liners under amalgam restorations on penetration by radioactive isotopes

Abstract The purpose of this study was to test the influence of cavity liners, under class V silver amalgam restorations, on the penetration of radioactive tracers through the filling margins and the underlying dentine. Two hundred and thirty-four newly extracted human teeth were used in this study. Eight different liners and bases were tested in four different isotope solutions. It was found that the films formed by a copal resin varnish and a polystyreneethylcellulose liner prevented dentine penetration of the isotopes via the filling margins and also decreased marginal penetration significantly. The calcium hydroxide liners completely blocked dentine penetration by the isotopes but tended to concentrate the radioactive solutions in the liner substance. Marginal penetration was slightly increased. Zinc oxide-eugenol bases decreased dentine penetration somewhat but did not decrease the degree of marginal penetration. Zinc phosphate cement increased dentine penetration markedly as well as penetration of negative ions into the amalgam substance. Marginal penetration also may have been slightly increased. Under the conditions of this experiment, copal resin varnish, polystyrene-ethylcellulose liner, and calcium hydroxide liners were effective in preventing penetration of radioactive ions into the dentine and pulp; zinc oxide-eugenol and zinc phosphate cement bases were not.

Effects of Filling Materials on the Pulp of the Rat Incisor

THIS investigation was designed to study the effects of a variety of commonly used filling materials upon the growing dentin and the pulp of the incisor of the albino rat. One of the important requirements of a dental filling material is that it does not harm the pulp. Investigators and clinicians have, therefore, stressed the need for a rapid and simple method of testing the effects of filling materials on the living pulp before these are used in human teeth. While histologic analysis of the effects of filling materials on the pulp in human teeth is essential to accuracy and objectivity, patients are reluctant to sacrifice teeth for experimental purposes. On the other hand, animal experiments permit the accumulation of relatively large numbers of specimens within a relatively short time. Most important, the conditions of testing can be more accurately controlled. The experiments can then be replicated until the variables are determined and the effects of each material on the pulp can be assessed in an objective and quantitative manner. Until very recently, the dog was the experimental animal of choice, with occasional studies in monkey and man. In 1952, one of us (I. S.) suggested the use of the rat incisor and molar for the analysis of the effects of filling materials on the young and adult pulp. One of the objectives of this study was to establish the validity of using the rat incisor for the bio-assay of new filling materials introduced to operative dentistry.

Relation of dental caries experience and gingivitis to cigarette smoking in males 17 to 21 years old (at the Great Lakes Naval Training Center).

This study was based upon the examination of 2,577 naval enlistees at the Great Lakes Naval Training Center. They represented a fair cross section of the youth living east of the Mississippi River. All were adult white males between the ages of 17 to 21 years. The number of DMF* teeth and tooth surfaces and the number of inflamed gingival units (PMA) in each person were calculated as previously described.3 Each person was asked to state the total number of cigarettes (or other tobacco) which he consumed per day.

Therapy conducive to healing of the human pulp

Abstract Factors that are conducive to pulpal healing and those that retard healing of the injured pulp are summarized. Much of the data are derived from a combination of empirical clinical observations and from controlled human and animal studies.

Remineralization of Carious Dentin

Based on radiographic and microradiographic evidence, a 10% stannous fluoride solution produced remineralization of the carious dentin more rapidly than, and was superior to, other remineralizing solutions and calcifying solutions. Permeability to dye penetration was reduced. Electron photomicrographs showed an electron-dense material deposited in the dentinal matrix.

Periapical tissue reactions after pulp exposure in rat molars

Apical periodontal lesions were produced in the rat molar by exposing the pulp to the oral environment. The natural history of the undisturbed lesion was studied at time intervals ranging from 2 days to 1 year postoperatively. The earliest reactions were usually inflammatory infiltration at the apex. The severity of the lesions was related to the amount of vital pulp still present in the tooth rather than to the time lapse after exposure. After 1 month most pulps has undergone necrosis and the lesions about the apices which followed showed two main types of reaction. In the case of the suppurative reaction, pus drained along a root surface, destroying the periodontal ligament and interradicular bone until it emerged at the gingival sulcus. The sinus tract could become lined with oral epithelium. In the reparative type of reaction, suppuration was absent or minimal and the apices were surrounded by fibrous connective tissue. The fiber bundles occasionally formed a collagenous scar, but they were usually replaced by cementum and bone with a new periodontal ligament. The width of the periodontium was never restored to its normal dimensions. Secondary destruction of the teeth occurred by fracture of cusps followed by caries which started in the exposed pulp chamber. Despite the predominance of destructive factors, spontaneous repair indicated good healing potential of the apical periodontal tissues.

Dental Caries and Gingivitis in Males 17 to 20 Years Old (At the Great Lakes Naval Training Center)

A LARGE number of enlistees from various parts of the United States were examined at the Great Lakes Naval Training Center. It was felt that the analysis of dental disease in this group would provide a good cross sectional sampling of young adult American men. These young men came predominantly from the Central, Northeastern, and Southeastern states with a few from scattered areas west of the Mississippi River. All enlistees were males between the ages of 17 and 20 years and all were white.