Effect of silane primers and unfilled resin bonding agents on repair bond strength of a prosthodontic microfilled composite

This study examined the effect of silane primers and bonding agents on bonding between layers of a light-activated composite material when repaired in the laboratory process. Disk specimens were prepared with the dentin portion of a composite material (Dentacolor DA-30) and abraded with a silicon carbide rotary cutting instrument. The specimens were conditioned with either one of the two silane primers (Porcelain Liner M and Silicer) or one of the two unfilled resin bonding agents (Dentacolor Opaker liquid and New Metacolor Photo Opaque liquid), or one of four combinations of two primers and two bonding agents. An intact surface with a thin air-inhibited unpolymerized layer, and an unprimed surface with only silicone carbide abrasion were also used for references. After placement of the enamel portion of the same brand of composite material (Dentacolor SA-30) on each surface of the dentin material, the specimens were light-exposed, and stored for 24 h in either dry or wet condition. Shear bond strengths were then determined with a mechanical testing device. The results showed that combined use of a silane primer and a bonding agent generally showed the greatest magnitude of bond strength regardless of material variation. The use of an unfilled resin bonding agent after application of a silane primer (Porcelain Liner M) is recommended to ensure adequate repair bonding between layers of the composite material.     

Reconstruction of the temporomandibular joint autogenous compared with alloplastic

The aims of and indications for temporomandibular joint (TMJ) reconstruction are well-established but the method of reconstruction is controversial. We describe a retrospective, two-centre audit of 49 patients treated with costochondral grafting and 50 patients treated with alloplastic joints. The characteristics of the patients were similar in both centres and the minimum follow-up period was 2 years. For each patient a number of variables were recorded including both subjective scores (pain and interference with eating) and objective data (interincisal distance). Patients in both groups showed an improvement in symptoms but more patients required reoperation in the autogenous group.     

Comparison of lip incompetence by remote video surveillance and clinical observation in children with and without cerebral palsy

This study aimed to compare two methods of assessing lip position so that an appropriate method could be used to assess whether a relationship existed between lip position and drooling in children with cerebral palsy. This investigation compared the use of a new, remote video surveillance (RVS) technique with direct clinical assessment of lip position by determination of intra- and inter-examiner agreement. Lip position was assessed in both techniques using the Jackson lip classification. Two groups of school children took part: one group suffered from cerebral palsy (CP), but the second group consisted of unaffected individuals. Based on Kappa statistics, intra- and inter-examiner agreements were generally found to be moderate for the individual methods (kappa = 0.48-0.54), whilst agreement between the two methods was found to be good (kappa = 0.68). The results showed moderately good examiner-agreement in the assessment of lip position, using either method and the Jackson lip classification. Consequently, lip position can be assessed by either RVS or direct clinical assessment, the choice depending on the physical circumstances surrounding the assessor and operator preference. However, RVS may offer a more unobtrusive approach.     

Patterns of cytokeratin expression in monkey and human periodontium following regenerative and conventional periodontal surgery

The pattern of cytokeratin expression has been extensively described in the normal and inflamed periodontium. However, there is no information regarding the pattern of cytokeratin expression in the periodontium which has been reformed following regenerative periodontal surgery. The aim of the present investigation was to evaluate the pattern of cytokeratin expression in the reformed human and monkey periodontium following regenerative and conventional periodontal surgery. In 3 monkeys, acute fenestration-type and chronic intrabony defects were treated with guided tissue regeneration (GTR), enamel matrix proteins (EMD), or coronally repositioned flap surgery (control). After a healing period of 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. Histological sections were cut with the microtome set at 3 microm. The sections were alternatively stained either with hematoxylin and eosin, or immunohistochemically by using one of the broad range monoclonal antibodies 34betaE 12 (for cytokeratins 1, 5, 10 and 14) or KL 1 (for cytokeratins 1, 2, 5, 6, 7, 8, 10, 11, 16 and 19), or one of the individual monoclonal antibodies LL025 (for cytokeratin 16), DC 10 (for cytokeratin 18), A53-B/A2 (for cytokeratin 19). Twelve patients, each displaying one deep intrabony defect scheduled for extraction due to advanced periodontitis or prosthetic reasons, were treated as described above. Following a healing period of 6 months, the teeth were extracted together with some of their surrounding soft and hard tissues. The histological and immunohistochemical processing of the human biopsies was identical to that described in monkeys. The results revealed that both the normal non-treated (original) monkey and human junctional epithelium stained strongly with all of the monoclonal antibodies used. The reformed junctional epithelium displayed the same cytokeratin expression pattern as the non-treated junctional epithelium. No differences regarding the cytokeratin expression pattern of the junctional epithelium were found between the treatments and types of healing (i.e. regenerative, through a new periodontal ligament, or reparative through a long junctional epithelium). In the intact periodontal ligament, the epithelial rests of Malassez displayed a comparable cytokeratin expression pattern to that of the junctional epithelium. However, no expression of cytokeratins was seen in the newly formed periodontal ligament. In such specimens, cytokeratin expression was observed only until the borderline between the regenerated cementum and the epithelial downgrowth. It was concluded that: a) the reformed junctional epithelium, following any type of surgical procedure, displays a similar pattern of cytokeratin expression to the original junctional epithelium; b) in the newly formed periodontal ligament, no expression of cytokeratins is present; and c) the epithelial rests of Malassez do not seem to reform after regenerative periodontal surgery.     

In vivo study of the pulp reaction to Fuji IX, a glass ionomer cement

OBJECTIVE: Our aims were to investigate the pulp biocompatibility of Fuji IX, a glass ionomer cement (GIC) used as a restorative material in cavities prepared in rat's upper molars, and to assess the value of this in vivo model for testing dental biomaterials. METHOD: Half-moon class V-like cavities were drilled on the mesial aspect of 26 rat upper first molars. Half of the experimental rats whose molars were restored with the GIC were killed after 8days and the second half after 30days. They were compared with two control groups, also submitted to cavity preparation, but with cavities left unfilled. Again, half of the control rats were killed at 8 days and the second half after 30days. Following intracardiac perfusion with the fixative solution, the specimens were processed to histologic procedures. RESULTS: After 8 days, in both groups a few inflammatory cells were observed. The odontoblastic layer was disrupted and dilated blood vessels were seen in the pulp area related to the cut tubules. The experimental group displayed a moderate inflammatory reaction whereas only a slight reaction was detected in the control group. In few teeth, bacteria were visualized in dentine tubules beneath the GIC restoration. Such colonies were not observed in unfilled molars.After 30days, in both groups, the pulp tissue recovered and displayed a normal appearance. Disruptions of the odontoblast layer were not visible anymore. Bacteria penetration into dentine tubules was reduced compared with the 8-day situation. A thick layer of reparative osteodentine was formed. However no difference in thickness was detected between the experimental and control groups, supporting that the formation of reparative dentine is not impaired. Irregular mineralizations including calcospherites were induced by the GIC. CONCLUSIONS: This study demonstrates that, despite small alterations in the mineralization processes, the GIC Fuji IX has a good biocompatibility and does not induce any harmful effect on pulp cells.     

Raman spectrometry applied to calcified tissue and calcium-phosphorus biomaterials]

The rigid part of the human body consists essentially of carbonated apatite (calcium phosphate). Biologists don't have any tools to study this "mineral" phase, though its origin is organic. A new approach of some compounds like enamel or bone is obtained with the Raman micro-characterisation by a very fine analysis of chemical bonds in a micrometric scale. This method allows the characterisation, the analysis and the dosage of ions, like carbonate, acid phosphates, proteins and fatty acids. The identification of other organic or mineral compounds (e.g. calcium carbonate, calcium oxide, substitutant ions...) is also possible. The Raman microspectrometry can also be used to study the chemical and physical properties of biomaterials and their evolution after implantation in a dental or bone site. On synthetical calcium phosphate, beta-TCP, brushite and hydroxyapatite can be distinguished and the impurities found in plasma spray deposits can be measured. The detection of alpha-, beta-, or gamma-pyrophosphates could be obtained in some commercial beta-TCP. The Raman microspectrometry is the only non-destructive method which allows the identification of the chemical bonds in a micrometric scale and gives the "fingerprint" of the studied component.     

Comparative analysis of antimicrobial action of polyhexametylenguanide hydrochloride (Biopag) and chlorhexidine bigluconate upon potential infectious agent of suppurative-inflammatory diseases of maxillo-facial region and neck

Sensitivity of microflora representatives isolated from inflammatory foci from 40 patients with suppurative-inflammatory diseases of maxillo-facial region and neck to different concentrations of antiseptic preparations of polyhexametylenguanide hydrochloride (Biopag) and chlorhexidine bigluconate was tested. It was determined that 0.05-0.1% solutions of these antiseptics were optimal for these diseases treatment. Biopag had more pronounced fungicidal action, less toxic and more prolonged antimicrobial action and better organoleptic properties when compared with chlorhexidine bigluconate.     

Use of N-butyl-2-cyanoacrylate tissue glue in thoracic duct injury during neck dissection surgery

Although thoracic duct injury is an uncommon complication of neck dissection, it can have a significant physiological and immunological impact on the patient's recovery as well as having more serious effects. We report a novel technique of using cyanoacrylate tissue glue for managing thoracic duct damage when this is noted at the time of neck dissection surgery.We have used this technique in four patients with no post-operative chyle leak or added complications.