The effect of inadequate access to peri-implant hygiene on marginal bone level. A 4-year cohort prospective study.

OBJECTIVE: The objective of this four-year cohort prospective study was to evaluate the effect of inadequate access to peri-implant hygiene on marginal bone level (MBL). MATERIAL AND METHODS: Forty-one partially edentulous patients (16 males and 25 females, aged 49.8 ± 11.9 years) who had implants with at least one year in function were selected. Patients were clinically and radiographically evaluated at three different times: baseline (T0), 2-year (T1), and 4-year (T2) follow-up intervals. At baseline, implants were classified and allocated into two groups: those presenting adequate access (ACC) and inadequate access (no-ACC) to peri-implant hygiene. A linear mixed-effects model for clustered longitudinal data was used to analyze MBL, probing depth (PD), plaque index (PI), and bleeding on probing (BoP). RESULTS: Of 131 implants, 74 were considered as having ACC, and 57 as having no-ACC at T0. Implants in the no-ACC group presented a statistically greater mean MBL measurement at T2 than implants in the ACC group (p = .011). In the no-ACC group, a significant reduction in PD from T0 to T1 (p = .019) and from T0 to T2 (p = .010) was observed. Regardless of the group, PI significantly increased at both T1 (p = .00001) and T2 (p = .00004). Regardless of time, the prevalence of BoP was significantly higher in the no-ACC group than in the ACC group (p = .012). CONCLUSION: Inadequate access to peri-implant hygiene frequently resulted in more peri-implant inflammation and MBL over time. Proper accessibility to peri-implant hygiene should be carefully considered during planning of implant restoration, and patients properly motivated into maintenance care.

Expression of neurotrophins and their receptors in primary osteosarcoma. / Expressão de neurotrofinas e de seus receptores no osteossarcoma primário.

OBJECTIVE: to determine the expression of neurotrophins and their tyrosine-kinase receptors in patients with osteosarcoma (OS) and their correlation with clinical outcomes. METHODS: we applied immunohistochemistry to biopsy specimens of patients consecutively treated for primary OS at a single institution between 2002 and 2015, analyzing them for expression receptors of tyrosine kinase A and B (TrKA and TrKB), neural growth factor (NGF) and brain derived neurotrophic factor (BDNF). Independently, two pathologists classified the immunohistochemical markers as negative (negative or weak focal) or positive (moderate focal/diffuse or strong focal/diffuse). RESULTS: we analyzed data from 19 patients (10 females and 9 males), with median age of 12 years (5 to 17.3). Tumors' location were 83.3% in the lower limbs, and 63.2% of patients had metastases at diagnosis. Five-year overall survival was 55.3%. BDNF was positive in 16 patients (84%) and NGF in 14 (73%). TrKA and TrKB presented positive staining in four (21,1%) and eight (42,1%) patients, respectively. Survival analysis showed no significant difference between TrK receptors and neurotrophins. CONCLUSION: primary OS samples express neurotrophins and TrK receptors by immunohistochemistry. Future studies should explore their role in OS pathogenesis and determine their prognostic significance in larger cohorts.

OBJETIVO: determinar a expressão de neurotrofinas e seus receptores tirosina quinases em pacientes com osteossarcoma (OS) e sua correlação com desfechos clínicos. MÉTODOS: biópsias de tumores primários de pacientes com OS tratados em uma única instituição, consecutivamente, entre 2002 e 2015, foram analisados através de imuno-histoquímica para expressão de receptores de tirosina quinase A e B (TrKA e TrKB), fator de crescimento neural (NGF) e fator neurotrófico derivado do cérebro (BDNF). De forma independente, dois patologistas classificaram os marcadores de imuno-histoquímica como negativos (negativos e focais fracos) ou positivos (moderado focal/difuso ou forte focal/difuso). RESULTADOS: foram analisados dados de 19 pacientes (10 do sexo feminino e 9 do masculino) com mediana de idade de 12 anos (5 a 17,3 anos). Dos tumores, 83,3% estavam localizados em membros inferiores e 63,2% dos pacientes eram metastáticos ao diagnóstico. A sobrevida global em cinco anos foi de 55,3%. BDNF foi positivo em 16 pacientes (84%) e NGF em 14 pacientes (73%). TrKA e TrKB apresentaram coloração positiva em quatro (21,1%) e oito (42,1%) pacientes, respectivamente. A análise de sobrevida não demonstrou diferença significativa entre receptores TrK e neurotrofinas. CONCLUSÃO: amostras de OS primário expressam neurotrofinas e receptores TrK através de imuno-histoquímica. Estudos futuros podem auxiliar na identificação do papel das mesmas na patogênese do OS e determinar se há possível correlação prognóstica.

Effects of the reinforced cellulose nanocrystals on glass-ionomer cements.

OBJECTIVE: Glass-ionomer cements (GICs) modified with cellulose nanocrystals (CNs) were characterized and evaluated for compressive strength (CS), diametral tensile strength (DTS) and fluoride release (F-). METHODS: Commercially available GICs (Maxxion, Vidrion R, Vitro Molar, Ketac Molar Easy Mix and Fuji Gold Label 9) were reinforced with CNs (0.2% by weight). The microstructure of CNs and of CN-modified GICs were evaluated by transmission electron microscopy (TEM) and by scanning electron microscopy (SEM) while chemical characterization was by Fourier transform infrared spectroscopy (FTIR). Ten specimens each of the unmodified (control) and CN-modified materials (test materials) were prepared for CS and DTS testing. For the fluoride release evaluation, separate specimens (n=10) of each test and control material were made. The results obtained were submitted to the t-test (p<0.05). RESULTS: The CN reinforcement significantly improved the mechanical properties and significantly increased the F- release of all GICs (p<0.05). The GICs with CNs showed a fibrillar aggregate of nanoparticles interspersed in the matrix. The compounds with CNs showed a higher amount of C compared to the controls due to the organic nature of the CNs. It was not possible to identify by FTIR any chemical bond difference in the compounds formed when nanofibers were inserted in the GICs. SIGNIFICANCE: Modification of GICs with CNs appears to produce promising restorative materials.

Expressão de neurotrofinas e de seus receptores no osteossarcoma primário / Expression of neurotrophins and their receptors in primary osteosarcoma

RESUMO Objetivo: determinar a expressão de neurotrofinas e seus receptores tirosina quinases em pacientes com osteossarcoma (OS) e sua correlação com desfechos clínicos. Métodos: biópsias de tumores primários de pacientes com OS tratados em uma única instituição, consecutivamente, entre 2002 e 2015, foram analisados através de imuno-histoquímica para expressão de receptores de tirosina quinase A e B (TrKA e TrKB), fator de crescimento neural (NGF) e fator neurotrófico derivado do cérebro (BDNF). De forma independente, dois patologistas classificaram os marcadores de imuno-histoquímica como negativos (negativos e focais fracos) ou positivos (moderado focal/difuso ou forte focal/difuso). Resultados: foram analisados dados de 19 pacientes (10 do sexo feminino e 9 do masculino) com mediana de idade de 12 anos (5 a 17,3 anos). Dos tumores, 83,3% estavam localizados em membros inferiores e 63,2% dos pacientes eram metastáticos ao diagnóstico. A sobrevida global em cinco anos foi de 55,3%. BDNF foi positivo em 16 pacientes (84%) e NGF em 14 pacientes (73%). TrKA e TrKB apresentaram coloração positiva em quatro (21,1%) e oito (42,1%) pacientes, respectivamente. A análise de sobrevida não demonstrou diferença significativa entre receptores TrK e neurotrofinas. Conclusão: amostras de OS primário expressam neurotrofinas e receptores TrK através de imuno-histoquímica. Estudos futuros podem auxiliar na identificação do papel das mesmas na patogênese do OS e determinar se há possível correlação prognóstica.

ABSTRACT Objective: to determine the expression of neurotrophins and their tyrosine-kinase receptors in patients with osteosarcoma (OS) and their correlation with clinical outcomes. Methods: we applied immunohistochemistry to biopsy specimens of patients consecutively treated for primary OS at a single institution between 2002 and 2015, analyzing them for expression receptors of tyrosine kinase A and B (TrKA and TrKB), neural growth factor (NGF) and brain derived neurotrophic factor (BDNF). Independently, two pathologists classified the immunohistochemical markers as negative (negative or weak focal) or positive (moderate focal/diffuse or strong focal/diffuse). Results: we analyzed data from 19 patients (10 females and 9 males), with median age of 12 years (5 to 17.3). Tumors' location were 83.3% in the lower limbs, and 63.2% of patients had metastases at diagnosis. Five-year overall survival was 55.3%. BDNF was positive in 16 patients (84%) and NGF in 14 (73%). TrKA and TrKB presented positive staining in four (21,1%) and eight (42,1%) patients, respectively. Survival analysis showed no significant difference between TrK receptors and neurotrophins. Conclusion: primary OS samples express neurotrophins and TrK receptors by immunohistochemistry. Future studies should explore their role in OS pathogenesis and determine their prognostic significance in larger cohorts.

Analytical method to estimate resin cement diffusion into dentin.

This study analyzed the diffusion of two resin luting agents (resin cements) into dentin, with the aim of presenting an analytical method for estimating the thickness of the diffusion zone. Class V cavities were prepared in the buccal and lingual surfaces of molars (n=9). Indirect composite inlays were luted into the cavities with either a self-adhesive or a self-etch resin cement. The teeth were sectioned bucco-lingually and the cement­dentin interface was analyzed by using micro-Raman spectroscopy (MRS) and scanning electron microscopy. Evolution of peak intensities of the Raman bands, collected from the functional groups corresponding to the resin monomer (C─O─C, 1113 cm(−1)) present in the cements, and the mineral content (P─O, 961 cm(−1)) in dentin were sigmoid shaped functions. A Boltzmann function (BF) was then fitted to the peaks encountered at 1113 cm(−1) to estimate the resin cement diffusion into dentin. The BF identified a resin cement­dentin diffusion zone of 1.8±0.4 µm for the self-adhesive cement and 2.5±0.3 µm for the self-etch cement. This analysis allowed the authors to estimate the diffusion of the resin cements into the dentin. Fitting the MRS data to the BF contributed to and is relevant for future studies of the adhesive interface.