OBJECTIVETo evaluate the bond strength of total-etch or self-etch dentin bonding agents after using two different dentin desensitizers on exposed dentin and investigate the bond interface by scanning electron microscope (SEM).

METHODSThirty intact and non-carious human third molars were used. The occlusal enamel was removed with the use of a slow-speed saw under water cooling. These teeth were divided into three groups using a table of random numbers with 10 teeth each. These three groups were treated with water (Group C), UltraEZ (Group U) and MI Paste (Group M) respectively. Then 10 teeth from each group were divided into A subgroup (n = 5) bonded with Single Bond 2 adhesive system and B subgroup (n = 5) bonded with Xeno III adhesive system according to manufacturers' instructions. A block of composite resin was build up to 4-5 mm. All the teeth were sectioned occluso-gingivally to obtain bar-shaped specimens with bonded surface area about 0.9 mm x 0.9 mm. The tension of the sample was tested by a microtensile tester at 1 mm/min. The mean values of bond strength were compared using one-way ANOVA. Three samples were chosen randomly from each of six groups for SEM investigation.

RESULTSThere were no significant differences between Group U and Group C both in A and B subgroups. While there were significant differences between Group M and Group C in two bonding-agent subgroups. For SEM, the hybrid layer was thin and dense in six groups. Both total-etch and self-etch bonding systems could get fair resin tag infiltration in Group C and Group U. In Group M, the resin tags were relatively shorter and fewer than the anterior mentioned two groups.

CONCLUSIONSUltraEZ had no effect on bond strength of both kinds of dentin bonding agents, while MI paste could diminish bond strength.

Bisphenol A-Glycidyl Methacrylate ; chemistry ; Dental Materials ; Dental Stress Analysis ; Dentin-Bonding Agents ; chemistry ; Humans ; Materials Testing ; Molar, Third ; Nitrates ; chemistry ; Potassium Compounds ; chemistry

OBJECTIVETo analyze stress distribution of two framework designs in compound galvano-ceramic bridges made with three-dimensional finite element models.

METHODSThree-dimensional finite element models were developed for compound galvano-ceramic bridges with two designed retainers of Ni-Cr frameworks which ringed or partially covered the electroformed gold caps. The models were vertically loaded 200 N on the center of the occlusal surface of the pontic and loaded 400 N on the center of buccoclusal marginal ridge from buccal aspect to lingual aspect at a 30 degree angle with the occlusion plane respectively. The stress distributions and the level of stress concentration in the two models were analyzed by the FEA software.

RESULTSStress distributing in two designed framework of compound galvano-ceramic bridges were similar. The highest von Mises stress of compound galvano-ceramic bridges was concentrated in the distal connector of the pontic and retainer. Under the vertical loading, the von Mises stress was 24.17 MPa for the partial cover retainer of the Ni-Cr framework and 24.85 MPa for the circular retainer. Under the lateral loading, the corresponding figures were 42.83 MPa and 42.69 MPa. No matter vertical or lateral loading, the margin of electroformed cap was the concentration area of the von Miese stress.

CONCLUSIONSIn this study, the stress concentration area of compound galvano-ceramic bridges with Ni-Cr framework and electroformed gold caps was the connector and the margin of electroformed cap was the insubstantial area.

Dental Prosthesis Design ; Denture, Partial, Fixed ; Finite Element Analysis ; Metal Ceramic Alloys ; Stress, Mechanical

OBJECTIVETo investigate the effect of putative periodontopathogenic bacteria on the development of drug-induced gingival overgrowth (GO) in renal transplant recipients.

METHODSA total of 57 patients undergoing cyclosporine treatment were divided into two groups according to GO index: with gingival overgrowth (group A) and without gingival overgrowth (group B). Demographic, pharmacologic and periodontal data were analyzed. The real-time polymerase chain reaction (PCR) method was used to detect and quantify five putative periodontopathogenic bacteria, including Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Prevotella intermedia (Pi), Treponema denticola (Td) and Tannerella forsythia (Tf) in subgingival samples. Moreover, the relationship between the bacterial amount and the severity of GO was analyzed.

RESULTSGroup A presented a significantly higher plaque index, sulcus bleeding index and probing depth than group B (P < 0.01). The occurrences of Pg, Td, and Tf in the group A (96%, 82% and 89%) were significantly increased compared with those in the group B (69%, 55% and 66%, P < 0. 05), respectively. The prevalence of Pg, Td, and Tf in the group A (79%) was markedly higher than that in the group B (38%, P < 0.01). The bacterial amount of Pg, Td, Tf and Pi were enhanced along with the severity of GO. However, the bacterial amount of Aa had no difference between two groups.

CONCLUSIONSPg, Td, and Tf may have a significant relationship with the development of GO.

Adult ; Aggregatibacter actinomycetemcomitans ; isolation & purification ; Bacterial Typing Techniques ; Cyclosporine ; adverse effects ; DNA, Bacterial ; Female ; Gingival Overgrowth ; chemically induced ; microbiology ; Humans ; Kidney Transplantation ; Male ; Middle Aged ; Polymerase Chain Reaction ; methods ; Porphyromonas gingivalis ; isolation & purification ; Prevotella intermedia ; isolation & purification ; Treponema denticola ; isolation & purification

OBJECTIVETo study the effects of Porphyromonas gingivalis (Pg) on the proliferation and apoptosis of vascular endothelial cell and to identify the role of Pg in the pathogenesis of atherosclerosis.

METHODSA cell culture model of vascular endothelial cell treated by Pg was used in vitro. The cells' ability of proliferation was measured by methyl thiazolyl tetrazolium assay, and cell cycle and the percentage of apoptosis with or without Pg invasion were examined by flow cytometry.

RESULTSInvasion of Pg could inhibit the proliferation of vascular endothelial cells at 72 h (F = 786.68, P < 0.01), and induce apoptosis at 24 h (F = 1074.56, P < 0.01). In addition, the cell cycle was arrested at G1 phase by the invasion of Pg W83 at 24 h (F = 43.23, P < 0.01) and ATCC 33277 at 48 h (F = 66.72, P < 0.01).

CONCLUSIONSPg may aggregate the inflammation of the vascular endothelial cells through induction of apoptosis, which could be one of the pathologic mechanisms in atherosclerosis.

Apoptosis ; Bacteroidaceae Infections ; physiopathology ; Cell Proliferation ; Cells, Cultured ; Endothelial Cells ; cytology ; Humans ; Porphyromonas gingivalis

Child, Preschool ; Humans ; Lymphatic Abnormalities ; diagnosis ; therapy ; Male ; Middle Aged

OBJECTIVETo introduce the method of retrograde embolization through the superficial temporal artery (STA) after the ligation of external carotid artery (ECA) for the treatment of craniofacial arterio-venous malformations (AVM).

METHODSSeven cases of craniofacial AVM were included in the study. After the ligation of ECA, the STA was surgically accessed and a 4F (1F = 0.333 mm) sheath introduced into the artery, and N-butyl-2-cyanoacrylate (NBCA) was selected as the permanent embolization material.

RESULTSThe angiogram was successfully carried out in these cases, which showed that some collateral branches from the ophthalmic artery of left internal carotid artery, vertebral artery and thyrocervical trunk provided the blood supply to the AVM nidus. The retrograde embolization with NBCA was completed.

CONCLUSIONSThe vascular architecture of craniofacial AVM after the ligated ECA was better demonstrated in angiogram of vertebral artery. The retrograde embolization through STA was an effective method for the treatment of craniofacial AVM.

Adolescent ; Adult ; Arteriovenous Malformations ; therapy ; Carotid Artery, External ; surgery ; Embolization, Therapeutic ; Face ; blood supply ; Female ; Humans ; Ligation ; adverse effects ; Male ; Middle Aged ; Young Adult

Hemangioma ; diagnosis ; surgery ; Humans ; Surgery, Plastic ; Vascular Malformations ; diagnosis ; surgery

Arteriovenous Malformations ; therapy ; Humans

Face ; blood supply ; Hemangioma ; therapy ; Humans ; Vascular Malformations ; therapy ; Vasculitis ; therapy

Dental Porcelain ; Dental Prosthesis ; methods ; Tooth Preparation