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ePaper created 2017-03-17, 12:41:55 | version 1.38.0
| industry Histomorphological changes in human bone After in vivo Er:YAG laser and ultrasound osteotomy Authors: Bistra Y. Blagova, Elena G. Poriazova, Petia F. Pechalova & Prof. Georgi T. Tomov, Bulgaria Introduction Bone surgical interventions are performed using two major techniques: an osteoplasty and osteot- omy. They are carried out by a great number of tools (osteotomes) which cause certain changes in bone morphology, i.e. cell vitality and physiology.1-14 The applicability of different osteotomes in bone sur- gery depends on the severity of tissues damage and the healing process afterwards.1 Therefore, the fea- tures of bone repair have been object of a many histomorphological research trials performed on laboratory animals.1–3 The analyses of the results published showed tissue recovery following ultra- sound and laser osteotomy to be superior to the pro- cedures performed by conventional rotary tools.1,4,5 However, the conclusions from these researches are not automatically relevant to humans. Therefore, the aim of this study was to evaluate the histological changes in the border area following in vivo human Tab. 1: Histopathological changes in 60 bone specimens taken in vivo from human mandibles by ultra- sound- and Er:YAG-laser osteotomy. Histopathological changes in 60 bone specimens Histomorphological changes Woodpecker® LiteTouch™, Light Instruments border configuration/ margins sharp, severely fragmented and irregular (Figs. 1 & 2) sharp, precise configuration (Figs. 3 & 4) debris fragments a satellite zone of numerous debris fragments (Figs. 1 & 2) no smear layer of debris fragments (Figs. 3 & 4) thermal damage/ carbonisation no significant signs, preserved bone microstructure (Figs. 1 & 2) no significant signs, mildly expressed darker superficial area (Figs. 3 & 4) 22 laser 1 2017 bone cutting by an ultrasonic device and an Er:YAG laser during extractions of impacted mandible wis- dom teeth. Materials and methods Objects in this study were outpatients aged be- tween 18 and 35 in order to minimise age-related bone changes. All patients were indicated for surgi- cal extraction of their mandibular third molars. Pres- ence of any co-morbidities or bone infection were considered as exclusion criteria. The research objects were sixty bone specimens divided into two groups equal in number according to the tool used for their collection: an ultrasonic surgical device (Wood- pecker Ultrasurgery®, China) and an Er:YAG laser (LiteTouch, Light Instruments®, Israel). All bone sam- ples were obtained by a trained oral surgeon. No complications occurred either intra- or postopera- tively. A standard setup of both devices for bone ma- nipulations were used as follows: – Ultrasonic unit—Bone function—Bone quality 1— frequency utilised up to 29.5 kHz—water pump 5; – LiteTouch™ Er:YAG laser—wavelength 2.94 µm (2,940 nm)—bone remodeling—Hard Tissue— Non- Contact mode—300 mJ—25 Hz—water spray 8. Laser specimens were obtained using a cylinder sapphire tip of 1.3 mm in diameter and 19 mm in length (LiteTouch™, Light Instruments, Israel) in a non-contact mode at a distance of 1–2 mm from the target surface. Ultrasound-obtained bone chips were taken by a tip # US 1. All samples were fixed in 10 % buffered formalin, decalcified and cut into slices within 3–5 µm each. The slices were stained with haematoxilin-eosin (H&E)