Biomechanical consideration regarding bone substitutes use in surgical treatment of chronic osteomyelitis

The main aim of this study is to present the use of bone substitutes in chronic ostheomielitis surgical treatment and its biomechanical influence. MATERIAL AND METHODS: First step is three-dimensional reconstruction to one femur using CT sections; the second is the reconstruction of infected bone volume, synthesis of material properties, synthesis of loading forces, synthesis of boundary condition and, finally, finite element analysis. RESULTS: The calculated Von Mises stress as a result of finite element analysis indicates that bone substitute implantation lead to a stress distribution in bone similar with a health femur.     

Bone healing pattern in surgically created circumferential defects around submerged implants: an experimental study in dog

Objective: To describe the healing of marginal defects below or above 1 mm of dimension around submerged implants in a dog model. Material and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full‐thickness flaps were elevated in the edentulous region of the right side of the mandible. Two recipient sites were prepared and the marginal 5 mm were widened to such an extent to obtain, after implant installation, a marginal gap of 0.5 mm at the mesial site (small defect) and of 1.25 mm at the distal site (large defect). Titanium healing caps were affixed to the implants and the flaps were sutured allowing a fully submerged healing. The experimental procedures were subsequently performed in the left side of the mandible. The timing of the experiments and sacrifices were planned in such a way to obtain biopsies representing the healing after 5, 10, 20 and 30 days. Ground sections were prepared and histomorphometrically analyzed. Results: The filling of the defect with newly formed bone was incomplete after 1 month of healing in all specimens. Bone formation occurred from the base and the lateral walls of the defects. A larger volume of new bone was formed in the large compared with the small defects. Most of the new bone at the large defect was formed between the 10‐ and the 20‐day period of healing. After 1 month of healing, the outline of the newly formed bone was, however, located at a similar distance from the implant surface (about 0.4 mm) at both defect types. Only minor newly formed bone in contact with the implant, starting from the base of the defects, was seen at the large defects (about 0.8 mm) while a larger amount was detected at the small defects (about 2.2 mm). Conclusion: Marginal defects around titanium implants appeared to regenerate in 20–30 days by means of a distance osteogenesis. The bone fill of the defects was, however, incomplete after 1 month. To cite this article:
Rossi F, Botticelli D, Pantani F, Pereira FP, Salata LA, Lang NP. Bone healing pattern in surgically created circumferential defects around submerged implants: an experimental study in dog.
Clin. Oral Impl. Res 23 , 2012; 41–48.
doi: 10.1111/j.1600‐0501.2011.02170.x     

Use of the connective tissue graft for the coverage of composite resin-restored root surfaces in maxillary central incisors

The purpose of this article is to report the use of the subepithelial connective tissue graft technique combined with the coronally positioned flap on a composite resin-restored root surface to treat Miller Class I gingival recessions associated with deep cervical abrasions in maxillary central incisors. Clinical measurements, including gingival recession height, probing depth, and bleeding on probing (BoP), were recorded during the preoperative clinical examination and at 2, 6, 12, and 24 months postoperatively. During the follow-up periods, no periodontal pockets or BoP were observed. The periodontal tissue of the teeth presented normal color, texture, and contouring. In addition, it was observed that creeping attachment had occurred on the restoration. This case report shows that this form of treatment can be highly effective and predictable in resolving gingival recession associated with a deep cervical abrasion.     

Effect of cariogenic biofilm challenge on the surface hardness of direct restorative materials in situ

Objectives

The presence of cariogenic biofilm could result in surface degradation of composite and ionomeric restorative materials. Thus, this study evaluated in situ the alterations in the surface microhardness of these materials under biofilm accumulation and cariogenic challenge.

Methods

In a split-mouth, double-blind, cross-over study, 10 volunteers wore palatal intra-oral devices containing bovine enamel slabs restored with composite resin (CR – Z250) or resin-modified glass ionomer (RMGI – Vitremer). Two phases of 14 days were carried out, one for each restorative material. In one side of the device, biofilm was allowed to accumulate under a plastic mesh, whereas in the opposing side, regular brushing was carried out 3 times/day with a dentifrice containing 1100 μg F/g as NaF. A 20% sucrose solution was applied extra-orally 10×/day on each restored dental slab. Knoop microhardness was used to calculate the percentage of surface hardness loss (%SHL).

Results

All materials showed a decrease in surface hardness after the in situ period. The restorative materials presented the following average for %SHL: RMGI without biofilm accumulation = 8.9 and with biofilm accumulation = 25.6, CR without biofilm accumulation = 14.7 and with biofilm accumulation = 17.0.

Conclusion

Biofilm accumulation and the presence of cariogenic challenge promoted faster degradation of ionomeric materials, but this was not observed for composite resin.

Clinical significance

The oral environment affects the surface hardness of aesthetic restorative materials. Biofilm accumulation and cariogenic challenge promote surface degradation for ionomeric materials, but not for composite resin.     

A randomized double-blind clinical trial of posterior composite restorations with or without bevel: 1-year follow-up

Objective

This randomized double-blind clinical trial compared the performance of posterior composite restorations with or without bevel, after 1-year follow-up.

Material and Methods

Thirteen volunteers requiring at least two posterior composite restorations were selected. Twenty-nine cavities were performed, comprising 14 without bevel (butt joint) and 15 with bevel preparation of the enamel cavosurface angle. All cavities were restored with simplified adhesive system (Adper Single Bond) and composite resin (Filtek P60). A halogen light curing unit was used through the study. Restorations were polished immediately. Analysis was carried out at baseline, after 6 months and after 1 year by a calibrated evaluator (Kappa), according to the FDI criteria. Data were statistically analyzed by Mann-Whitney test (p<0.05).

Results

Beveled and non-beveled cavities performed similarly after 1 year follow-up, regarding to fractures and retention, marginal adaptation, postoperative hypersensitivity, recurrence of caries, surface luster and anatomic form. However, for surface and marginal staining, beveled cavities showed significantly better performance (p<0.05) than butt joint restorations.

Conclusions

It was concluded that the restorations were acceptable after 1 year, but restorations placed in cavities with marginal beveling showed less marginal staining than those placed in non-beveled cavities.     

Accuracy of direct examination and culture as compared to the anatomopathological examination for the diagnosis of chromoblastomycosis: a systematic review

BackgroundChromoblastomycosis is a skin infection caused by dematiaceous fungi that take the form of muriform cells in the tissue. It mainly manifests as verrucous plaques on the lower limbs of rural workers in tropical countries.ObjectivesThe primary objective of this review is to evaluate the accuracy of diagnostic methods for the identification of chromoblastomycosis, considering the histopathological examination as the reference test.MethodsMEDLINE, LILACS and Scielo databases were consulted using the terms “chromoblastomycosis” AND “diagnosis”. The eligibility criteria were: studies that evaluated the accuracy of tests for the diagnosis of chromoblastomycosis. Eleven studies were selected. Statistical analysis included the calculation of sensitivity and specificity of the diagnostic methods.ResultsConsidering the histopathological examination as the reference test, the culture showed a sensitivity (S) of 37.5% - 90.9% and a specificity (Sp) of 100%; while direct mycological examination showed S = 50% - 91.6% and Sp of 100% . Considering the culture as the reference test, the serology (precipitation techniques) showed S of 36% - 99%; and Sp of 80% - 100%; while the intradermal test showed S of 83.3% - 100% and Sp of 99.4% - 100%.Study limitationsThe small number of studies and very discrepant sensitivity results among them do not allow the calculation of summary measures through a meta-analysis.ConclusionsDirect mycological examination, culture, intradermal test and serology show sensitivity and specificity values ??for the diagnosis of chromoblastomycosis with no significant difference between the studies.     

The spectrum of computerized tomography (CT) findings in central nervous system (CNS) infection due to Cryptococcus neoformans var. gattii in immunocompetent children

Cranial CT scans of eleven immunocompetent children with central nervous system (CNS) infection due to Cryptococcus neoformans var. gattii were retrospectively reviewed. These children had an average age of 8.8 years and positive culture for C. n. var. gattii in cerebrospinal fluid. The most common signs and symptoms were headache, fever, nuchal rigidity, nausea and vomiting. No normal cranial CT was detected in any patient. Hypodense nodules were observed in all patients. The remaining scan abnormalities were as follows: nine had diffuse atrophy, six had hydrocephalus, and five had hydrocephalus coexistent with diffuse atrophy.     

Time-dependent modulation of AMPA receptor phosphorylation and mRNA expression of NMDA receptors and glial glutamate transporters in the rat hippocampus and cerebral cortex in a pilocarpine model of epilepsy

The pilocarpine model in rodents reproduces the main features of mesial temporal lobe epilepsy related to hippocampus sclerosis (MTLE-HS) in humans. It has been demonstrated in this model that the phosphorylation of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR1 subunit is increased 1 h after pilocarpine treatment. Moreover, alterations in the levels of glutamate transporters have been associated with chronic epilepsy in humans. Despite these studies, the profile of these changes has not yet been addressed. We analyzed the protein content and phosphorylation profile of the AMPA receptor GluR1 subunit by western blotting. We also used quantitative real-time polymerase chain reaction to analyze the expression of glial glutamate transporters and the N-methyl-d-aspartate receptor NR1 subunit in the hippocampus (Hip) and cerebral cortex (Ctx) at different time points after pilocarpine-induced status epilepticus (Pilo-SE) in male adult Wistar rats. Biochemical analysis was performed in the Hip and Ctx at 1, 3, 12 h (acute period), 5 days (latent period), and 50 days (chronic period) after Pilo-SE. Key findings include an increase in the phosphorylation of GluR1-Ser⁸⁴⁵ in the Ctx and GluR1-Ser⁸³¹ in the Hip at different times during the acute period, and a decrease in the total content of the GluR1 subunit in the Ctx in the latent period. There was a down-regulation of the mRNA expression and protein levels of EAAT1 and EAAT2, and a decrease of the NR1 mRNA expression, in the Ctx during the latent period. Notably, during the chronic period, the EAAT2 mRNA expression and protein levels decreased while the NR1 mRNA levels increased in the Hip. Taken together, our findings suggest a time- and structure-dependent imbalance of glutamatergic transmission in response to Pilo-SE, which might be associated with either epileptogenesis or the seizure threshold in MTLE-HS.