A preliminary study of hardness and modulus of elasticity in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy

Objectives: To investigate the quality of newly formed bone in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy (LLLT), based on hardness and modulus of elasticity values. The ideal moment for laser application (during the latency/activation period vs. during the bone consolidation period) was also evaluated. Computed tomography imaging was used to assess relapse as a result of early device removal. Study design: Extraoral distraction devices were placed in five sheep so as to achieve 1.5 cm of lengthened bone in 60 days. Distraction devices were removed 50, 40, and 33 days after surgery. Four animals were treated with LLLT, at different times, and one was used as control (no LLLT). Results: When applied during the bone consolidation period, LLLT caused an increase in hardness and modulus of elasticity values. On the other hand, animals irradiated with LLLT during the latency/activation period presented a delay in bone healing. A period of consolidation of 13 days (early device removal) was associated with relapse. Conclusions: Nanoindentation tests were able to detect slight abnormalities in bone metabolism and proved to be important tools for the assessment of bone quality following distraction osteogenesis. LLLT provided increased benefits when applied during the bone consolidation period, once it promoted an increase in hardness and modulus of elasticity values. According to our results, the bone consolidation period should be of at least 3 weeks, so as to prevent relapse. © Medicina Oral S. L

Analysis of the morphology and composition of tooth apices apicectomized using three different ablation techniques

Objectives: To investigate apicectomies performed using burs, a CO2 laser or an Er:YAG laser and to evaluate the following aspects: morphology of apicectomized surfaces, presence of failures at the dentin/obturation material interface (marginal fit) of the apical portions of the root canals, and the proportions of chemical elements in the apicectomized surfaces. Study design: Twenty-four teeth were divided into three groups of eight and each group underwent apicectomy by one of three different ablation techniques: bur, CO2 laser or Er:YAG laser. The morphology of the apicectomized surfaces was then analyzed using scanning electron microscopy and their chemical composition was analyzed by energy dispersive spectroscopy. Results: Surfaces produced with ablation by bur exhibited less surface irregularities and better marginal fit, while ablation with the CO2 laser caused intense surface carbonization and failures in obturation material fit. Conclusions: Our results suggest that, taking into consideration their clinical application, ablation of tooth apices using burs proved to be the best option among those tested here

Analgesic action of laser therapy (LLLT) in an animal model

Objectives: To evaluate the analgesic effect of laser therapy on healthy tissue of mice. Study design: Forty-five animals were divided in three groups of 15: A ? infrared laser irradiation (830 nm, Kondortech®, São Carlos, SP, Brazil); B ? red laser irradiation (660 nm, Kondortech®, São Carlos, SP, Brazil); C ? sham irradiation with laser unit off. After laser application, the mice remained immobilized for the injection of 30 µl of 2% formalin in the plantar pad of the irradiated hind paw. The time that the mouse kept the hind paw lifted was measured at 5 min intervals for 30 minutes. Results: Results showed statistically significant differences comparing the control group with the infrared laser group at 5, 20, 25 and 30 accumulated minutes, and with the red laser group at all time points. The analysis of partial times, at each 5 minutes, showed statistically significant differences between the control and the laser groups up to 20 minutes. Conclusions: Laser therapy had an analgesic effect and red laser had the best results

Importância epidemiológica de acidentes com motocicletas e bicicletas no contexto atual do trauma bucomaxilofacial no sul do Brasil

Purpose: Epidemiological studies exhibit regional variation patterns as the result of local demographic and socioeconomic factors. This study assessed the epidemiology of maxillofacial fractures treated at a trauma center in Southern Brazil to identify the importance of motorcycle and bicycle crashes. Methods: The records of 2261 patients admitted between April 2003 and March 2013 were reviewed. Results: The male-to-female ratio was 5.6:1. The peak incidence occurred in the third decade of life. Bicycle and motorcycle crashes accounted for 20% of all reported etiologies. Mandibular and orbitozygomatic complex fractures were most prevalent. The most common treatments were open reduction with rigid internal fixation and conservative therapy. Overall, 1248 patients (55.9% of recorded admissions) had a length of stay of 7 days or less. Conclusion: Countrywide prevention projects and the use of alternative transportation should be encouraged.Objetivo: Pesquisas epidemiológicas têm padrões de variações como resultado de fatores demográficos e socioeconômicos locais. Para identificar a importância dos acidentes de motocicletas e bicicletas, foram avaliadas as características epidemiológicas de fraturas maxilofaciais em um hospital público referência de trauma no sul do Brasil. Metodologia: A avaliação foi realizada através da análise de 2261 prontuários de pacientes internados entre abril de 2003 e março de 2013. Resultados: A razão entre homens e mulheres foi de 5,6:1. O pico de incidência foi observado na terceira década de vida e os acidentes de bicicleta e motocicleta atingiram 20% dentre os agentes etiológicos informados. As fraturas de mandíbula e do complexo zigomático-orbitário foram as mais prevalentes. Os tratamentos mais realizados foram: a redução cruenta com fixação interna rígida e o método conservador, sendo que 1248 pacientes (55,9% dos períodos de internação registrados) passaram até sete dias no hospital. Conclusão: Concluiu-se que projetos de prevenção contra acidentes e uso de transportes alternativos em todo país são necessários

Histological evaluation of the effect of low-level laser on distraction osteogenesis in rabbit mandibles

Objectives: This study evaluated the action of low level laser therapy (LLLT) on the percentage of newly formed bone in rabbit mandibles that underwent distraction osteogenesis (DO). Study design: Ten rabbits underwent bone lengthening according to the following protocol: Latency ? 3 days; Activation ? 7 days 0.7 mm/d; and Consolidation ? 10 days. The control group was composed of 4 rabbits. The experimental group, composed of 6 rabbits, received infrared GaAlAs LLLT (?=830 nm, P=40 mW) according to the following protocol: point dose of 10 J/cm2 applied directly on the bone site that underwent DO during bone consolidation at 48-hour intervals. Results: The percentage of newly formed bone was greater in the LLLT group (57.89%) than in the control group (46.75%) (p=0.006). Conclusion: The results suggest that LLLT had a positive effect on the percentage of newly formed bone. Betterquality bone sites may allow early removal of the osteogenic distractors, thus shortening total treatment time

Análise biomecânica de osso mandibular submetido a distração osteogênica e LLLT

O objetivo deste trabalho é apresentar o Método de Elementos Finitos na análise do tecido neoformado de osso da mandíbula de ovelha submetida a distração osteogênica e posterior aplicação de laser LLLT, que constitui-se de uma seqüência de procedimentos, incluindo a técnica cirúrgica. Para tanto, foi instalado distrator extra-bucal em ovelha com intuito de neoformar 1,5 cm de osso em 60 dias de observação. O animal foi irradiado com laser infravermelho. A partir de tomografias realizadas na mandíbula, foi gerado um biomodelo tridimensional, no qual foi realizada a análise (Tensões de Von Misses, deslocamento do implante, deformação óssea, etc.), em ambiente computacional CAE

Análise biomecânica de osso mandibular submetido a distração osteogênica e LLLT

O objetivo deste trabalho é apresentar o Método de Elementos Finitos na análise do tecido neoformado de osso da mandíbula de ovelha submetida a distração osteogênica e posterior aplicação de laser LLLT, que constitui-se de uma seqüência de procedimentos, incluindo a técnica cirúrgica. Para tanto, foi instalado distrator extra-bucal em ovelha com intuito de neoformar 1,5 cm de osso em 60 dias de observação. O animal foi irradiado com laser infravermelho. A partir de tomografias realizadas na mandíbula, foi gerado um biomodelo tridimensional, no qual foi realizada a análise (Tensões de Von Misses, deslocamento do implante, deformação óssea, etc.), em ambiente computacional CAE

Proliferação in vitro de células tronco da medula óssea humana sobre discos de cimento de αlfa-trifosfato de cálcio e titânio

Objectives: to evaluate human bone marrow stem cells (HBMSC) cultured on α -tricalcium phosphate cement (α -TCP) and titanium (Ti) discs, as well as the osteoconductive properties of these biomaterials. Methods: discs of α -TCP and commercially pure Ti were manufactured and placed on polyethylene plates. Cells were cultured according to the following: group I – control (no discs); group II – α-TCP discs; group III – Ti discs. Propidium iodide staining was used to assess cell proliferation. Cells cultures were analyzed at 3, 7, 14 and 21 days. Results: Proliferation occurred in both biomaterials. At 3 days, greater cell proliferation was seen in group II than group III (p=0.01). Differences were not significant on the other time periods. Morphologic analysis showed circular morphology in group I, compatible with osteogenic cell lineage. Conclusions: both biomaterials were osteoconductive but not osteoinductive. This did not affect the initial stages of osteogenesis.Objetivos: avaliar culturas de células tronco da medula óssea humana (HBMSC) sobre discos de cimento de α -trifosfato de cálcio (α -TCP) e titânio (Ti), bem como a propriedade de osteocondução destes biomateriais. Métodos: discos de α -TCP e Ti comercialmente puro foram confeccionados e colocados em placas de polietileno. As culturas celulares foram distribuídas da seguinte forma: grupo I – controle (sem discos); grupo II – discos de α -TCP; grupo III – discos de Ti. Foi utilizado iodeto de propídio para possibilitar a constatação da proliferação celular. As culturas celulares foram avaliadas em 3, 7, 14 e 21 dias. Resultados: a proliferação das HBMSC ocorreu em ambos os biomateriais. No terceiro dia, uma maior proliferação celular foi constatada no grupo II e-m relação ao grupo III (p=0,01). Nos demais períodos não foram constatadas diferenças significativas. A análise morfológica demonstrou células com morfologia circular no grupo I, compatíveis com linhagem osteogênica. Conclusões: ambos biomateriais mostraram-se osteocondutores, mas não osteoindutores, não interferindo nos estágios iniciais da osteogênese

Hiperdontia

The presence of fourth molars is a rare condition. The radiographic exam is fundamental for itsdetection, since in most cases the supernumerary teeth are impacted. A case of fourthmandibular molars is presented. Prevalence, diagnostic images and surgical treatment arediscussed

Finite element analysis of masticatory stress on neoformed bone tissue after distraction osteogenesis and low-level laser therapy : a pilot study

Objective: This study aimed to understand the action of masticatory forces on an implant virtually introduced into the sheep mandible after distraction osteogenesis and low-level laser therapy (LLLT) by using finite element analysis. Background data: Distraction osteogenesis as an alternative for bone reconstruction that may be used in the treatment of deformities. Methods: Four ewes underwent distraction osteogenis to elongate the left mandibular body by 15 m, and three of them underwent LLLT with the purpose of improving bone properties. After death, animals were scanned by computed tomography and their mandibles were tridimensionally reconstructed by computer programs. The physical properties related to hardness and modulus of elasticity of each animal were obtained from the dissected mandibles, and data were transferred to Femap software for finite element analysis. Results: Animals exposed and not exposed to LLLT irradiation showed remarkably similar values for superficial hardness and modulus of elasticity, without statistically significant difference ( p > 0.05), between the values observed for the cortical bone and the cancellous bone among the groups. The neoformed mandible, after a brief period for bone healing, was able to promote stability for implant placement and proper distribution of masticatory forces. Conclusions: An implant introduced virtually into the site of bone neoformation did not suffer any micromotions relevant to osteointegration. Furthermore, finite element analysis showed that the neoformed portion of the mandible was able to absorb and distribute masticatory forces throughout its structure, even after a brief period for bone maturation