Monkey Teeth Research Articles

Short-term extrusion of isolated teeth of adult monkeys ( Macaca fascicularis)

By means of a variable capacitance device, the occlusal movements of 12 fully-developed teeth were recorded in 6 adult monkeys. Sustained extrusion was seen, with rhythmic pulsations due to the heart beat and to breathing. Extrusion varied from 10 to 138 μm over periods of 40–360 min, and became progressively slower with time. Because of the protracted nature of the extrusion, it is probable that these tooth movements were caused by forces generated in the periodontal ligament resulting from biochemical changes in the periodontium rather than by vascular alterations, and occurred as a result of the removal of intrusive loads from the opposing teeth.

Mitoses and microorganisms in the periodontal membrane after storage in milk or saliva.

Milk and saliva were tested in vitro as potential storage media for avulsed teeth. Developing monkey teeth were extracted and stored in milk or saliva for periods ranging from 1 to 6 h. The osmolality, pH, conductivity and number of viable bacteria in the media were determined after predetermined intervals during the storage periods. After the storage periods the teeth were either prepared for scanning electron microscopy or cultured for 24 h in Eagle's medium supplemented with 3H-thymidine. In the scanning electron microscope numerous adherent bacteria were seen covering the periodontal membrane after storage in saliva but none were found after storage in milk. The cultured teeth were sectioned and evaluated with autoradiography. Superficial parts of the periodontal membrane were rapidly injured by storage in saliva while the epithelial root sheath and the apical pulpal cells were affected at a later stage. Cells neighboring the cementoblasts incorporated 3H-thymidine after 6 h storage in milk but not after storage in saliva for the same length of time. It was concluded that the low osmolality in combination with bacteria which adhered to the periodontal membrane made saliva less suited than milk for long time storage of avulsed teeth. Furthermore, a viable layer of cells close to the root surface seemed to be a prerequisite for a successful healing without root resorption after replantation.

Hard-tissue resorption and deposition after preparation and disinfection of the root canal

H ard-tissue resorption and deposition following endodontic instrumentation was studied histologically in monkey teeth at the root canal wall, the root surface, and the lamina dura by van Mullem and associates.’ They reported that after 7 days resorption was slight at the root canal wall and the root surface and was significantly more intense than physiologic replacement of bone by osteoclasts at the lamina dura. After 42 days the reaction had subsided at the three sites, but none of the tissues had returned to normal. In a study by the same authors2-4 on the inflammatory reaction to several root canal disinfectants containing formaldehyde, hard-tissue resorption and deposition phenomena were observed also. The aim of this investigation was to quantify: (1) the resorption-deposition reaction at several experimental periods at the root canal wall, the root surface, and the lamina dura after instrumentation followed by disinfection and (2) a possible cumulative effect of instrumentation and disinfection, using cresol and formaldehyde (Formocresol) and several alcohol and formaldehyde (Alcoformol) prescriptions as disinfectants.

Storage of experimentally avulsed teeth in milk prior to replantation.

Extracted monkey teeth were endodontically treated, stored in milk or saliva for two or six h, and then replanted. Periodontal conditions were evaluated after eight wk. Teeth that had been stored for two or six h in milk or for two h in saliva showed periodontal healing almost as good as that of immediately replanted teeth. Teeth that had been kept in saliva for six h or bench-dried for one h showed extensive replacement resorption. Milk may thus be recommended as a storage medium for ex-articulated teeth prior to replantation in cases when immediate replantation is not possible.

Strange Things, Gross Terms, Curious Customs: The Rehearsal of Cultures in the Late Renaissance

IN THE AUTUMN OF 1599, Thomas Platter of Basle visited the London apartments of Walter Cope-gentleman, adventurer, and member of Elizabeth's Society of Antiquaries-to view Cope's collection of curiosities gathered from around the world. No catalogue of the objects displayed in the room could presume to be complete. Platter himself records only a selection, but he does take an evident pleasure in compiling his list a plaisir de conter akin to that which Jean Ceard has found at work in contemporaneous accounts of nature's oddities and marvels, such as the anonymous Histoire prodigieuses published in 1598.1 It is a pleasure in the recollection, literally, of such wonders as an African charm made of teeth, a felt cloak from Arabia, and shoes from many strange lands. An Indian stone axe, a thunderbolt. A stringed instrument with but one string. The twisted horn of a bull seal. An embalmed child, or Mumia. The bauble and bells of Henry VIII's fool. A unicorn's tail. Inscribed paper made of bark, and an artful Chinese box. A flying rhinoceros (unremarked), a remora (explicated at some length), and flies of a kind that glow at night in Virginia instead of lights, since there is often no day there for over a month. There are the Queen of England's seal, a number of crowns made of claws, a Madonna made of Indian feathers, an Indian charm made of monkey teeth. A mirror, which both reflects and multiplies objects. A sea-halcyon's nest. A sea mouse (mus marinus), reed pipes like those played by Pan, and a long narrow Indian canoe, with oars and sliding planks, hanging from the ceiling. They are all strange things, frembden Sachen.2 The canoe lodged on the ceiling may have been a convention of sorts, judging from its promiscuity of appearance in other and better-known collections of the same variety (Fig. 1). Cope's room is a Kunst or Wunderkammer, a wonder-cabinet: a form of collection peculiar to the late Renaissance, characterized primarily by its encyclopedic appetite for the marvellous or the strange and by an exceptionally brief historical career.3 The first Wunderkammer was established in Vienna in 1550; for perhaps one hundred years such collections flourished, but by the middle of the seventeenth century they were rapidly vanishing. As early as The Advancement of Learning (1605), where Bacon calls for the substantial and severe collection of the Heteroclites or Irregulars of nature, wonder-cabinets were derided as frivolous impostures for

The pulpal effect of freezing temperatures applied to monkey teeth

When temperatures below −80° C, are applied to intact monkey teeth via a liquid nitrogen probe for 1, 2, or 3 minutes, an increasing degree of pulpal damage occurs, but all pulps remain vital. The lesion appears to be predictable and is characterized by a distinct layer of coronal secondary dentin with cellular inclusions, odontoblast destruction, and microvascular injury. The root pulp remains essentially healthy and uninflamed. Periodontal and root tissue damage was also observed.

Pulp reactions to experimental exposures in young permanent monkey teeth.

Exposures of the dental pulp complicate the treatment of fractured teeth. If the root formation is incomplete, the choice of treatment rests between pulp capping and pulpotomy; alternatively pulpectomy and conventional root therapy must be carried out. Treatment planning is dependent on the clinical assessment of the degree of pulp damage and the extent of the pulp inflam- mation. Invariably, the time lapse between pulp exposure and treatment may amount to several hours and even to days. Experi- mental studies on rats, dogs and monkeys

PH changes in calcium hydroxide-covered dentin

The pH of dentin in teeth with calcium hydroxide and zinc oxide-eugenol filled cavities was studied in freeze-sectioned young monkey's teeth by means of pH indicators. In untreated dental tissues, the range of pH was found to be 6.4 to 7.4, and the same range of pH was observed when the dentin had been covered with zinc oxide-eugenol. Dentin covered by calcium hydroxide showed a pH range of 11.4 to 12.2 one to three days after application. Seven days after application of calcium hydroxide, the dentin nearest the cavity still showed a pH range of 11.4 to 12.2, whereas the pulpal part showed a pH range of 7.4 to 8.0.

Circulating antibodies after experimental chronic infection in the root canal of teeth in monkeys

Root canals of 49 teeth with necrotic pulp tissue in five monkeys were infected with Streptococcus faecalis ss liquefaciens, Actinomyces bovis, Fusobacterium nucleatum, Peptostreptococcus anaerobius, and Bacteroides oralis in various combinations. After 6 months the root canals and the periapical tissues were subjected to radiographic, bacteriologic, and histologic examinations. Signs of periapical inflammation were radiographically registered in 41 teeth, most frequently in teeth inoculated with a mixed flora. In 11 out of 16 teeth infected separately with Strep. faecalis ss liquefaciens, apical periodontitis was observed. Sera from the monkeys prior to and after the experimental inoculation were analyzed by means of gel diffusion, hemagglutination (HA), and complement binding test for antibodies against different antigen preparations of the homologous bacterial strains used for the inoculation. Detectable antibodies were seen with antigens of B. oralis in all five monkeys. Agglutinating antibodies were demonstrated with lipopolysaccharide-antigen of B. oralis in titers between 1:40 and 1:320. A marked reduction of the antibody level against lipopolysaccharide (LPS) antigen after mercaptoethanol treatment indicated that a main part of the antibodies registered was of IgM-class. The study shows that certain antigens of bacterial origin from infected root canals, while affecting the periapical tissues, also stimulate the production of circulating antibodies.

Migration of leukocytes in dental pulp in response to plaque bacteria.

Cell material from three different dental plaque bacteria (Actinomyces viscosus, Streptococcus mitis, Actinobacillus actinomycetemcomitans) were studied for their capacity to induce leukocyte migration in the dental pulp of monkeys. Altogether five animals were used to provide 123 teeth for the study. The bacterial test materials were prepared from lyophilized sonicates of pure cultures of respective bacteria mixed with crystalline bovine serum albumin (BSA) 1:1 by weight. Immediately prior to use in the experiment saline was added to render the test material into a paste-like consistency. Buccal Class V cavities were prepared in the monkey teeth leaving a thin remaining wall to the pulp. In these cavities, the test materials were enclosed for a period of 8 h. A set of control cavities received BSA alone. Placement of test and control materials were made before and after depleting the animals of serum complement by repeated injections of Cobra Venom Factor. Histologic examination of pulp tissue specimens showed that materials from two of the bacterial species (A. viscosus, Act. actinomycetemcomitans) consistently induced infiltrations of polymorphonuclear leukocytes in one to several cell layers underneath the test cavity. The material from S. mitis seemed less potent and in 11 of 22 teeth no pulpal reaction was recorded. Inactivation of complement with Cobra Venom Factor did not appear to affect the severity of the pulpal responses.

Rate of formation of regular and irregular secondary dentin in monkey teeth

An in vivo hard-tissue labeling technique was used to study the formation of regular and irregular secondary dentin in thirty-one monkey teeth. The formation of regular secondary dentin averaged 0.8 μm per day. No difference was found in the rate of formation of regular secondary dentin and irregular secondary dentin associated with attrition. The formation of irregular secondary dentin following restorative procedures averaged 2.9 μm per day. During the first 30 postoperative days less irregular secondary dentin was formed subjacent to deep cavities as compared to shallow ones. This could be the result of an initial injury to the odontoblasts caused by the operative and/or restorative procedures.

The effects of different splinting times on replantation of teeth in monkeys

The purpose of the study was to examine histologically the tissue changes affecting the teeth and surrounding structures after using both 7- and 30-day fixation periods on replanted teeth in monkeys. Eight adult male rhesus monkeys were used. The maxillary central and lateral incisors were extracted, treated endodontically, reimplanted, and temporarily immobilized with an interproximal acid-etch splint. The splints were removed at 1 week in half of the teeth and at 30 days in the other half. The monkeys were killed at 7 and 14 days, and at 1, 2, 3, 4, 5, and 6 months postoperatively. The results showed that replanted teeth that were splinted for 7 days recovered uneventfully, whereas the teeth that were splinted for 30 days demonstrated increased areas of root resorption and ankylosis. Thus, it is suggested that after tooth replantation the periodontium will repair rapidly with a shorter time of splinting (7 days). Extended splinting periods (30 days) seem to induce further root resorption and dentoalveolar ankylosis.

A study of freeze-dried (lyophilized) cortical bone used as an apical barrier in adult monkey teeth

Thirty-two fully formed vital teeth of four adult cynolmolgus monkeys were endodontically prepared to simulate conditions of an open apex. The apical 2 to 5 mm of 24 teeth were filled with freeze-dried cortical bone. The eight remaining teeth received no implant material and served as controls. All the teeth were obturated with gutta-percha. The monkeys were killed at 5, 14, 24, and 28 weeks, and specimens were prepared for histologic examination. The early specimens showed localized acute inflammation with general organizational healing apically, whereas later specimens showed osseous healing. Some experimental teeth had mineralized tissue resembling osteocementum occupying the canal. Freeze-dried cortical bone was found to be a biocompatible material that can be used effectively as a substitute barrier against which gutta-percha can be condensed in mechanically prepared open-apexed monkeys' teeth.

A procedure to achieve controlled pulp exposure: an explorative experiment.

The present paper reports the development of a method by which controlled pulp exposure can be achieved. Buccal cavities in teeth of adult monkeys were prepared by very slow intermittent cutting, using air as a coolant. During each intermission the electrical resistance of the tissues was measured by means of direct current. One electrode contacted the gingiva and the other was bur itself. The resistance values were related to observations in histological sections of the teeth. Under the conditions described, pulp exposure occurred at an electrical resistance of about 10 mega-ohm (M omega).

The effect of pulpotomy using Formocresol on blood vessel architecture in primary anterior teeth of Macaca rhesus monkeys

Pulpotomies, using Formocresol medicament, were performed on monkey primary anterior teeth. After the teeth were extracted, the pulpal blood vessels were perfused with India ink. The vascular architecture was intact throughout the pulp except immediately adjacent to the amputation where blood vessels appeared to be greatly reduced in number. This area appeared to be a zone of necrotic debris and clotted blood. Pulpotomies, using Formocresol medicament, were performed on monkey primary anterior teeth. After the teeth were extracted, the pulpal blood vessels were perfused with India ink. The vascular architecture was intact throughout the pulp except immediately adjacent to the amputation where blood vessels appeared to be greatly reduced in number. This area appeared to be a zone of necrotic debris and clotted blood.

A root canal disinfectant with reduced formaldehyde concentration. Cytotoxicity and anti-microbiol effectiveness under clinical conditions in monkey teeth.

SummaryFour formol‐alcohol compounds of different formaldehyde and ethanol concentrations (FA 3·15/20, FA 6/15, FA 8·75/30 and FA 8·75/60), were studied for anti‐microbial effectiveness and periapical tissue reaction in a clinical experiment in monkeys.Using FA 6/25, the periapical inflammatory reaction was minimal and anti‐microbial effectiveness appeared to be sufficient in infected teeth at the end of a 7 day period. Five weeks after the 1 week dressing period the periapical tissue reaction had returned to the level of the controls.

A study of freeze-dried (lyophilized) dentin used as an apical barrier in adult monkey teeth

Thirty-two fully formed vital teeth of four adult cynomolgus monkeys were endodontically prepared to simulate conditions of an open apex. The apical 2 to 5 mm. of 24 teeth were filled with freeze-dried dentin. The eight remaining teeth received no implant material and served as controls. All the teeth were obturated with gutta-percha. The monkeys were sacrificed at 6, 13, 23, and 27 week periods, and the specimens were prepared for histologic examination. The early specimens showed acute inflammation apically; later specimens showed osseous healing. Some experimental teeth had partial cementum bridging against the implant material. Freeze-dried dentin was found to be a biocompatible material which can be used effectively as a substitute barrier against which gutta-percha can be condensed in mechanically prepared open-apexed monkey teeth.

Gingivitis induced by gingival impaction in monkeys

Experimental gingival impaction with elastic bands causes gingivitis, pocket formation, and displacement of teeth in monkeys. Following the removal of the elastic bands, there is resolution of the gingivitis with long epithelial attachment rather than fibrous repair of the periodontal ligament.

The development of enamel structure in rat incisors as compared to the teeth of monkey and man.

The rat incisor is an excellent model system in which to study amelgenesis. However, the information obtained has not been extrapolated to the human because of alleged structural differences between the teeth. The obvious differences include continuous eruption in rat incisors and an enamel rod pattern in rats which seemingly differs from the keyhole pattern of human enamel. A comprehensive analysis was made of those features of enamel structure considered fundamental to the understanding of its formation. This was done by applying the knowledge of amelogenesis obtained in rat incisors to the teeth of monkey and man. The following points of basic similarity were established between these species: (1) Interrod enamel is secreted first. It forms the side walls of cavities which are initially occupied by Tomes' processes. (2) The formation of interrod cavities is followed by deposition of enamel rods within these spaces. (3) The rods conform to the shape of the cavities and are secreted from one surface of Tomes' process. (4) At the initial site of rod deposition its enamel is continuous with the interrod enamel wall. (5) Growth of the rod compresses the process to one side of the cavity resulting in an arcade-shaped "space" between the rod and the remaining interrod walls. This study demonstrates that it is no longer necessary to postulate a keyhole structure for primate enamel, and it has established that a fundamental similarity exists in the basic structure and in the mode of formation of enamel in all three species.

Periodontal healing of exarticulated monkey teeth stored in milk or saliva.

Saliva has usually been recommended as a storage medium for exarticulated teeth. Recent tissue culture studies have, however, shown that milk has a more suitable osmolality than saliva and that milk is a better storage medium for human periodontal ligament cells. In the present investigation periodontal healing of replanted monkey teeth has been studied after storage of teeth in milk or saliva before replantation. There was much less root resorption, especially inflammatory resorption, after storage in milk than in saliva. Storage of teeth in milk for 3 h before replantation resulted in the same low frequency of root resorptions as was seen after immediate replantation. There was hardly any replacement resorption (ankylosis) seen in the replanted teeth.