Confocal scanning optical microscopy of a 3-million-year-old Australopithecus afarensis femur.

Portable confocal scanning optical microscopy (PCSOM) has been specifically developed for the noncontact and nondestructive imaging of early human fossil hard tissues, which here we describe and apply to a 3-million-year-old femur from the celebrated Ethiopian skeleton, "Lucy," referred to Australopithecus afarensis. We examine two bone tissue parameters that demonstrate the potential of this technology. First, subsurface reflection images from intact bone reveal bone cell spaces, the osteocyte lacunae, whose density is demonstrated to scale negatively with body size, reflecting aspects of metabolism and organismal life history. Second, images of a naturally fractured cross section near to Lucy's femoral mid-shaft, which match in sign those of transmitted circularly polarized light, reveal relative collagen fiber orientation patterns that are an important indicator of femoral biomechanical efficacy. Preliminary results indicate that Lucy was characterized by metabolic constraints typical for a primate her body size and that in her femur she was adapted to habitual bipedalism. Limitations imposed by the transport and invasive histology of unique or rare fossils motivated development of the PCSOM so that specimens may be examined wherever and whenever nondestructive imaging is required.

The antiscorbutic action of L-ascorbic acid and D-isoascorbic acid (erythorbic acid) in the guinea pig.

Female guinea pigs were fed a scorbutigenic diet supplemented with either L-ascorbic acid or D-isoascorbic acid or combinations of these. Their responses were judged by changes in body weight, serum alkaline phosphatase levels, wound healing, and tooth structure. Large additions (100 mg daily) of D-isoascorbic acid to the scorbutigenic diet resulted in normal growth over a 7-wk period and normal serum alkaline phosphatase levels, tooth structure development, and collagen formation after wounding. The addition of 0.5 or 5.0 mg of L-ascorbic acid to this high D-isoascorbic diet improved neither growth rate nor collagen deposition during wound healing. On the basis of changes in tooth structure, D-isoascorbic acid has 1/20 the potency of L-ascorbic acid. Its effect is additive to subminimal maintenance levels of L-ascorbic acid implying that there is no competitive inhibition in the utilization of the two compounds. The relatively weak activity of D-isoascorbic acid is probably due to poor transport to the tissues and ineffective binding to functional sites. This explains why the onset of scurvy is much more rapid after withdrawal of D-isoascorbic acid from the diet when it had been the sole antiscorbutic dietary constituent. It is concluded that D-isoascorbic acid is a "weakly" antiscorbutic agent on the basis that it is both poorly absorbed and retained by the tissue; that in fact it may, to the degree that it is taken up by the tissues and retained, be equal in antiscorbutic potency to L-ascorbic acid.

Laterally repositioned "stimulated" osteoperiosteal pedicle grafts in the treatment of denuded roots. A preliminary report.

In order for successful coverage of denuded roots to be accomplished, correctly applied fundamental biological principles must be considered in the choice and utilization of the surgical modality. In this report some representative clinical cases are presented to indicate favorable results that may be achieved with stimulated osteoperiosteal pedicle flaps. These cases are part of an ongoing clinical and statistical evaluation.

Regeneration of attachment apparatus lost due to disease of endodontic origin.

Osseous defects may be due to endodontic or to periodontic involvement or a combination of the two. Careful diagnosis is required to determine the correct form of treatment.

The gingival autograft and gingivectomy.

A rationale and technique for the utilization of the combined procedures of the gingival autograft and the gingivectomy technics for the purpose of pocket elimination and creation of an adequate zone of attached gingiva has been presented. It allows for the predictable and relatively atraumatic treatment of gingival problems in which there has been no deformity of the underlying osseous structures.

A long term clinical study evaluating the effect of two dentifrices on oral tissues.

1. A long term (54 months) supervised, double-blind human clinical study has been conducted to ascertain whether the routine use of a commercially available cosmetic dentifrice, with purported stain removal and flavor impact characteristics, would cause adverse manifestations in the oral tissues, as compared to the similar use of a more conventional type of commercially available dentifrice. 2. One hundred and twenty male and female subjects (aged 12 to 70) were randomly assigned to the use of one of the two dentifrices under investigation, after which they used the assigned dentifrices twice daily (1 min each brushing) under supervised conditions for a period of 54 months. 3. Clinical examinations were conducted on all subjects initially (base line), and at 3-month intervals throughout the 54-month course of the study. This examination included a complete and thorough inspection of the oral soft and hard tissues. 4. The results after 54 months of continuous use of the dentifrices (representing a total dentifrice/oral tissues exposure time of approximately 45 hours per subject) indicated that neither of the two dentifrices caused any adverse reactions of the oral soft tissues and that both dentifrice groups had similar patterns and levels of cervical abrasion and/or erosion. 5. The results also indicate a lack of direct correlation between laboratory abrasivity values (as determined by a radioactive dentin abrasion procedure) and the clinical situation, thus suggesting that factors other than dentifrice abrasivity may play an important role with regard to tooth wear.

Sulcular exudate protein levels as an indicator of the clinical inflammatory response.

Protein concentrations in gingival fluid exudate were obtained in both the clinically minimal and severe inflammatory states. A comparison of the results indicated no significant differences in the two groups studied. Since total protein concentrations do not appear to reflect accurately the clinical inflammatory status of the gingival tissues, specific components of the protein molecule should be studied.

Stimulated osteoperiosteal pedicle grafts in dogs.

This descriptive study compared the healing of mucoperiosteal and "stimulated" osteoperiosteal flaps for the treatment of surgically created periodontal recessions in dogs. Surgically created defects on the canine teeth of 10 healthy mongrel dogs were covered by specially designed, cemented copper bands for 4 weeks (Several maxillary premolar teeth were managed in the same way). A plaque and calculus-promoting diet was fed to the animals during this period. When the bands were removed the diet was altered and an intensive oral hygiene program was instituted. The contralateral tooth, chosen randomly, was utilized for placement of the mucoperiosteal lateral sliding flap and acted as the control. The experimental side was surgically stimulated 21 days prior to elevation of a "stimulated" osteoperiosteal flap for repositioning over the denuded roots. The animals were sacrificed with an overdose of Nembutal and block sections for histologic study were taken at periods ranging from 14 to 50 days. Histologic findings indicate that healing of the stimulated flaps was accompanied by the formation of a relatively short dentogingival epithelium, cementogenesis which varied in amount and type, and new connective fiber insertion into cementum. By contrast, the mucoperiosteal flaps healed with a long dentogingival epithelial relationship and no cementogenesis or connective tissue reattachment.

Correlative light and backscattered electron microscopy of bone--Part I: Specimen preparation methods.

A method for preparing nondecalcified bone and tooth specimens for imaging by both light microscopy (LM) and backscattered electron microscopy in the scanning electron microscope (BSE-SEM) is presented. Bone blocks are embedded in a polymethylmethacrylate (PMMA) mixture and mounted on glass slides using components of a light-cured dental adhesive system. This method of slide preparation allows correlative studies to be carried out between different microscopy modes, using the same histologic section. It also represents a large time savings relative to other mounting methods whose media require long cure times.

Correlative light and backscattered electron microscopy of bone--part II: automated image analysis.

Detailed studies of biological phenomena often involve multiple microscopy and imaging modes and media. For bone biology, various forms of light and electron microscopy are used to study the microscopic structure of bone. Integrating information from the different sources is necessary to understand how different aspects of the bone structure interact. To accomplish this, methods were developed to prepare and image thin sections for correlative light microscopy (LM) and backscattered electron imaging in the scanning electron microscope (BSE-SEM). Images of the same fields of view may then be analyzed for degrees of relationships between specimen features not observed by LM or SEM alone. These methods are applied here to study possible associations between the degree of bone mineralization and pattern of collagen fiber orientation in the mid-shaft of the human femur. The "relational images" obtained allow us to examine the relationship between these two variables, both objectively and quantitatively.

An unusual cutaneous reaction secondary to allopurinol.

A 60-year-old man presented with erythematous papules and plaques on his body as well as a violaceous indurated nodule on his face. A cutaneous drug reaction secondary to allopurinol was considered. Examination of biopsy specimens revealed a dense lymphocytic infiltrate of the skin as is seen in lymphocytoma cutis. The lesions cleared promptly after use of allopurinol was discontinued. A literature review showed that an eruption of this kind, including a nodule on the face that histologically simulated a lymphocytic infiltrate of the skin, has not yet been reported secondary to allopurinol.

Photodistributed hypertrophic lichen planus in association with acquired immunodeficiency syndrome: a distinct entity.

The cutaneous manifestations of human immunodeficiency virus infection include papulosquamous diseases, viral and fungal infections, and neoplastic disorders. Eczematous photosensitivity disorders have been reported in patients infected with the human immunodeficiency virus. We describe a patient with advanced acquired immunodeficiency syndrome who developed photodistributed hypertrophic lichen planus. We believe this is a distinct cutaneous manifestation of human immunodeficiency virus infection.

The role of the dental specialist in the hospital.

As can be seen from this incomplete list of dental specialties and functions they perform in the hospital, there is an increasing participation of dental specialists in the delivery of total health care to the hospitalized patient. In order to disseminate knowledge further of the special protocols of hospital practice and of special hospital dentistry problems, the American Association of Hospital Dentists was formed and publishes a journal containing this special information.