Immunocytochemical examination of immune cells in periapical granulomata and odontogenic cysts

Monoclonal antibodies (mAbs) were used to determine the presence and distribution of immune cells including lymphocytes, macrophages and Langerhans cells, in normal periodontal ligament, periapical granulomata, periapical cysts and dental developmental cysts. Isolated T-lymphocytes, but not B-lymphocytes, were detected in specimens of non-inflamed periodontal ligament. Increased numbers of T and B lymphocytes were found in all of the lesions examined. Monocytes/macrophages were associated with most periapical granulomata, dental developmental cysts and all periapical cysts. Langerhans cells, intraepithelial lymphocytes, and monocytes/macrophages were not detected in the rests of Malassez but were found in some epithelia within periapical granulomata and in most epithelial linings of odontogenic cysts. Increased numbers of immune cells were seen around proliferative epithelia and adjacent to the epithelial linings of cysts. Epithelium, particularly that of odontogenic cysts, showed positive reactions for HLA-Dr, lysozyme and for α-1 antitrypsin. The presence of immune cells in periapical granulomata and odontogenic cysts, suggests that cell-mediated and humoral immunoreactions occur in these lesions and may be associated with the epithelial proliferation within the periapical lesions.     

Relationship between compressive strength and cervical shaping of the all-ceramic Cerestore crown

The two types of cervical shaping recommended for the preparation of Cerestore crowns are shoulder or deep chamfer. 14 specimens shaped like stylized Cerestore crowns on a shoulder preparation and 14 on a deep chamfer preparation were produced. Thereafter each crown was placed on the epoxy resin die on which it had been produced. 7 epoxy dies from each of the two series were shortened 1 mm occlusally in order to elucidate the importance of the cervical shaping. Placed on its own epoxy die each of the 28 Cerestore crowns was then subjected to occlusal stress until fracture occurred. The force needed for fracture was three times greater for the crowns produced on a shoulder preparation than for those produced on a chamfer preparation. No significant differences was obtained when crowns with the same cervical shaping were tested on intact and shortened dies respectively.     

γ2 phase in conventional dental amalgams — discrete clumps or continuous network? A review

A bstract — Six different types of sources of evidence are examined to study the controversy of whether the γ ₂ phase in conventional dental amalgams occurs in discrete clumps or as a continuous network.
Evidence obtained from corrosion studies, volume-fraction analysis studies and amalgam microstructure studies and evidence associated with the alloy type, the structure of the γ ₂ phase and manipulative techniques are investigated.
Although, under certain conditions, the γ ₂ phase may form a continuous network there is evidence to indicate that, using a conventional Ag₃Sn-based alloy and techniques providing adequate mercury removal, the γ ₂ phase occurs in discrete clumps.     

Attachment, growth and synthesis by human gingival fibroblasts on demineralized or fibronectin-treated normal and diseased tooth roots

Regeneration of a fibrous attachment to tooth roots previously exposed to periodontal pockets requires interaction between the root surface and fibroblasts. Experiments were designed to assess whether or not fibroblasts will attach, grow and synthesize normally on tooth roots and determine the efficacy of various treatments of diseased root surfaces on these activities. Extracted teeth were collected, washed and stored frozen until used. The roots were sectioned and the surface area determined. All roots were thoroughly planed to remove most of the cementum and some were then treated with fibronectin or citric acid. Each root was placed in a Linbro well and a suspension of fibroblasts in Dulbecco Vogt medium with 10% fetal calf serum added. After cell attachment, each root was transferred to a fresh well and incubated. Some roots were examined by scanning electron microscopy. Attachment and growth were assessed by harvesting and counting cells after various incubation times. The pattern of protein synthesis was determined by preparing fluorographs from cultures pulse labeled with radioactive S35-methionine. Cells attach and grow on planed root surfaces. The number that attach to normal and diseased roots is greatly enhanced by pretreatment with fibronectin or citric acid. By day three, the cells become confluent at approximately 20,000/cm2. The pattern of proteins produced is comparable to that seen in cultures maintained in petri dishes. After root planing, cells attach, grow and synthesize equally well on diseased and normal roots.     

Aberrant blastogenic response to LPS in experimental gingivitis of elderly subjects.

The blastogenic response of peripheral blood leukocytes to lipopolysaccharide (LPS), phytohemagglutinin (PHA) and LPS/PHA mixtures was followed over a short course of experimental gingivitis in elderly subjects (65-81 years) who strictly avoided oral hygiene procedures for periods up to 9 d. The leukocytes responded poorly to LPS, PHA and to LPS/PHA combinations. The concomitant heightened sensitivity of the gingiva to dental plaque among the elderly subjects may relate to the altered leukocyte response in this age group.     

Advanced glycation endproducts (AGEs) induce oxidant stress in the gingiva: a potential mechanism underlying accelerated periodontal disease associated with diabetes

We hypothesized that one mechanism underlying advanced periodontal disease in diabetes may involve oxidant stress in the gingiva, induced by the effects of Advanced Glycation Endproducts (AGEs), the irreversible products of non-enzymatic glycation and oxidation of proteins and lipids which accumulate in diabetic plasma and tissue. Infusion of AGE albumin, a prototypic ligand, into mice resulted in increased generation of thiobarbituric acid reactive substances (TBARS) compared with infusion of non-glycated albumin in the gingiva, as well as in the lung, kidney and brain. Pretreatment of the animals with the antioxidants probucol or N-acetylcysteine (NAC) prevented the generation of TBARS in the gingiva. Affinity-purified antibody to AGEs demonstrated increased immunoreactivity for AGEs in the vasculature and connective tissues of the gingiva in streptozotocin-induced diabetic mice compared to non-diabetic controls. Increased immunoreactivity for AGEs was also demonstrated in the gingiva of diabetic humans compared with non-diabetic individuals via immuno-histochemistry and ELISA. Consistent with these data, immunohistochemistry for heme oxygenase-1, a marker of enhanced oxidant stress, was increased in the gingival vasculature of diabetic mice and humans compared with non-diabetic controls. These data suggest that AGEs present in diabetic gingiva may be associated with a state of enhanced oxidant stress, a potential mechanism for accelerated tissue injury.     

Comparative implant research in dogs: a prosthodontic model.

One-hundred twenty endosteal dental implants were inserted bilaterally in the mandibles of 30 adult mongrel dogs after bilateral extraction of all premolars. The 120 implants were evenly divided into one- and two-stage systems and included ceramic and titanium cylindrical root-form implants and titanium blade implants. The research design of this investigation divided the 30 animals into 10 groups of three dogs. This article describes an animal model that is useful in evaluating dental implant designs and compares the results with those from humans. In particular, this article delineates the prosthodontic approach appropriate for this model using one- and two-stage titanium implants. Rexillium alloy fixed prostheses were placed on 32 endosteal implants and 16 natural mandibular molar teeth. The implants and prosthetic components of the Sterio-Oss implant system were used. All prostheses are functional with minimal maintenance. To date, after 1-year of follow-up, none of the implants have been lost and none of the fixed prostheses have required recementation or maintenance other than normal hygiene. Histologic and survival data as well as results with other implant systems will be presented in other reports.     

Gingival lesions of HIV infection in 178 Greek patients.

One hundred seventy-eight HIV-infected Greek patients were examined and the gingival lesions were recorded. At the time of oral examination, 77 patients were HIV positive, 53 had ARC, and 48 had AIDS. The mean age of the patients was 36.6 years; 158 were men and 20 were women. Fifteen different gingival lesions were recorded. Necrotizing gingivitis (10.1%), gingivitis (5.0%), periodontitis (18.5%), candidiasis (5.8%), and Kaposi's sarcoma (5.0%) were the most common lesions observed. Oral lymphomas and other lesions were recorded in low numbers. Our findings show that dentists should be aware of gingival lesions of HIV disease because some of them are common and diagnostically important.