Periodontal repair in dogs: evaluation of a bioresorbable calcium phosphate cement (Ceredex) as a carrier for rhBMP-2

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to induce clinically relevant bone formation for orthopedic, craniofacial, and oral indications. It appears critical, in particular for onlay indications, that the associated carrier technology exhibits structural integrity to offset compressive forces in support of rhBMP-2-induced bone formation. The objective of this study was to evaluate a calcium phosphate (CP) cement, Ceredex, as a candidate carrier for rhBMP-2 in a defect model with limited osteogenic potential. MATERIALS: Bilateral, critical size, 6-mm, supra-alveolar, periodontal defects were created in six, adult, male, Hound Labrador mongrels. Three animals received rhBMP-2/Ceredex (rhBMP-2 at 0.20 and 0.40 mg/ml) in contralateral defect sites (implant volume/defect approximately 1 ml). One defect site in each of the three remaining animals received Ceredex without rhBMP-2 (control). The animals were euthanized at 12 weeks postsurgery for histologic and histometric analysis. RESULTS: Mean induced bone height exceeded 80% of the defect height for supra-alveolar periodontal defects receiving rhBMP-2/Ceredex without major differences between rhBMP-2 concentrations compared with approximately 40% for the control. The newly formed bone, a mixture of lamellar and woven bone in fibrovascular tissue, circumscribed relatively large portions of the residual Ceredex biomaterial. Inflammatory lesions were associated with limited bone formation in some sites. From a periodontal perspective, sites receiving rhBMP-2/Ceredex exhibited increased cementum formation compared with control, but without a functionally oriented periodontal ligament, and increased ankylosis and root resorption. Control sites exhibited early wound failure and exposure, loss of the Ceredex biomaterial, and limited bone formation. CONCLUSIONS: The Ceredex CP cement appears a potentially promising carrier technology for rhBMP-2 onlay indications. However, a slow resorption rate may prevent its wider use. This study does not support use of the rhBMP-2/Ceredex combination for periodontal indications.     

Relationship of subgingival plaque flora to lysosomal and cytoplasmic enzyme activity in gingival crevicular fluid

Examining the relationships among indicators of the acute inflammatory response in gingival crevicular fluid (GCF) and specific bacterial species in subgingival plaque may provide indications of which bacterial species or groups of species may be associated with potentially destructive host-derived processes. Here we report on the relationship of the subgingival plaque flora to the activity of mammalian forms of the enzymes beta-glucuronidase (beta G), lactate dehydrogenase (LDH), and arylsulfatase (AS) in GCF from a total of 54 4-6 mm periodontal sites from 13 periodontitis patients. Sites were scored for probing depth (PD) and bleeding on probing, and GCF was collected using filter paper strips inserted into the sulcus for 30 s, eluted in buffer and assayed for enzyme activity. 1 week later, the patients were again evaluated for PD and bleeding, and subgingival plaque was removed with a curette oriented toward the pocket epithelium. Plaque samples were examined by darkfield microscopy and cultured anaerobically on selective and non-selective media. Various groups of bacteria, including species of black pigmenting Bacteroides (BPB), Fusobacterium sp., Capnocytophaga sp, Streptococcus sanguis, and total facultative organisms were enumerated. Relationships among the enzymes and bacterial groups expressed as colony-forming unit (CFU) counts or as a % of the total cultivable flora were assessed by Spearman correlation analysis. beta G levels were significantly correlated with populations of spirochetes, B. intermedius, B. gingivalis, and total lactose negative BPB's. Correlation between beta G and F. nucleatum sp. or Capnocytophaga sp. approached but did not reach statistically significant levels. In contrast, LDH activity showed a significant positive correlation with levels of B. gingivalis and total lactose negative BPB's. AS levels were significantly correlated only with B. gingivalis. beta G and LDH showed a significant negative correlation with levels of coccoid forms. Thus, beta G, an acid hydrolase which can serve as a marker for primary granule release from polymorphonuclear leukocytes, was most closely correlated with the micro-organisms found in other studies to be associated with chronic adult periodontitis.     

Treatment of inflammatory salivary gland diseases by using intraductal UV irradiation

A novel technique is offered for treatment of sialadenitis. Ultraviolet irradiation conductors are inserted into the gland via its major duct for subsequent intracorporeal UV therapy of the gland. The results of the treatment are analyzed in 57 cases of sialadenitis observed during 1 to 2.5 years. The technique proved effective enough to be recommended for practical application.     

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.     

Radiographic examination of ectopically erupting maxillary canines

This study analyzes the need for and possibility of obtaining further information from different radiographic procedures in 125 children with potential ectopic eruption of the maxillary canines. After clinical examination of 3,000 10 to 15-year-old children, it was found that 7% needed radiographic examinations for determination of the canine position. Eighty-four children (2.8%), with a total of 125 potential ectopically erupting maxillary canines diagnosed clinically and by means of periapical radiographs, were selected and a stepwise extended radiographic diagnostic procedure was used. Most canines in ectopic eruption were positioned palatally; the positions could be assessed with sufficient accuracy from conventional periapical films in 92% of the cases. Only in 37% of the cases, however, could the lateral incisor be projected free from the ectopic canine by the intraoral technique. The lamina dura of the lateral incisor facing the canine was often found to be interrupted. For 29% of the ectopic canines, the lateral incisors could neither be projected free nor judged free from resorptions and a supplementary polytomographic investigation was believed to be necessary. The number of resorbed teeth was doubled by polytomography and altogether 12.5% of the ectopic canines caused resorptions. A stepwise radiographic procedure including polytomography is described and recommended in cases of ectopic eruption of maxillary canines for determining the correct position and ruling out or confirming resorptions on incisors, thereby optimizing the orthodontic treatment planning.     

Successful self-replantation of avulsed tooth with 42-year follow-up

Abstract This report presents a case of a 55-year-old woman who was hit in the mouth 42 years ago. The maxillary right central incisor was avulsed. The patient's mother replanted the tooth within 10–20 minutes and “splinted” it with aluminium foil from a cigarette package and a piece of cardboard. Clinical and radiographic examination after 42 years revealed a slightly discolored asymptomatic right central incisor. The root canal space was obliterated and no signs of root resorption or periapical radiolucency were observed.     

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.     

ELISA and conventional techniques for identification of black-pigmented Bacteroides isolated from Periodontal pockets

Conventional biochemical characterization and an ELISA technique were compared for their ability to identify reference cultures and fresh isolates from suppurating and non-suppurating periodontal pockets, as well as healthy gingival sulci in the same individual. Antisera to Bacteroides gingivalis strain 381, Bacteroides intermedius strains 581 and VP1 8944, and Bacteroides melaninogenicus ss. melaninogenicus strain 287 were prepared by immunizing rabbits. The antisera were conjugated with peroxidase and appropriate dilutions were chosen to minimize cross-reactions in the ELISA technique. Conventional characterization of the isolates included cellular and colonial morphology, biochemical characterization, and gas liquid chromatography of acid end products. The antisera appeared to be specific for each black-pigmented species, since cross-reactions were not observed to reference strains of heterologous species. There was a 94% agreement between the ELISA and conventional identifications of over 300 fresh isolates from periodontal sites.
The predominant black-pigmented Bacteroides species isolated from suppurating sites was Bacteroides intermedius using either identification technique. The median value of proportions of this species was significantly increased in the suppurating periodontal pockets (16.5%) when compared to non-suppurating deep periodontal pockets (3%) and healthy gingival sulci (0%). Significant differences in proportions were not observed for the other species of black-pigmented Bacteroides .