Cutting characteristics of ultrasonic surgical instruments

Heat Generation During Initial Osteotomy for Implant Site Preparation: An In Vitro Measurement Study

Introduction

Controlling temperature generation during implant site preparation is important to prevent implant early failure.

Aim

The present in vitro study aimed at measuring temperature variation generated during the initial osteotomy using both rotatory and piezo-surgical inserts.

Methods

Nine groups were defined according to drill and insert type, cooling volume (mL/min) and cooling temperature. A total of 315 implant site preparations were performed in an artificial bone sample and the temperature was measured using an infrared camera. Drills’ wear was assessed using scanning electron microscopy at baseline and after 10 and 35 utilizations.

Results

Piezo-surgical insert groups determined a temperature increase that was significantly higher than the one generated by rotatory drills groups (p < 0.001). When considering rotatory drills groups a temperature ≥ 40 °C was never recorded.

Conclusion

Lower saline temperature implied a significant temperature decrease (p < 0.001), while the increase in cooling volume did not imply a temperature decrease. The scanning electron microscopy analysis of the drills demonstrated that little drill wear occurred up to 35 utilization times.

Influence of Piezosurgery on Bone Healing around Titanium Implants: A Histological Study in Rats

The aim of this study was to evaluate histomorphometrically the influence of two techniques of dental implant site preparation on bone healing around titanium implants. Fifteen male Wistar rats (±300 g) were used in the study. Each tibia was randomly assigned to receive the implant site preparation either with a conventional drilling technique (control - DRILL group) or with a piezoelectric device (PIEZO group). The animals were sacrificed after 30 days and then the following histomorphometric parameters were evaluated (percentage) separately for cortical and cancellous regions: proportion of mineralized tissue (PMT) adjacent to implant threads (500 μm adjacent); bone area within the threads (BA) and bone-implant contact (BIC). The results demonstrated that there were no statistically significant differences between both groups for cancellous BIC (p>0.05) and cortical PMT (p>0.05). On the other hand, a higher percentage of BA was observed in the PIEZO group in the cortical (71.50±6.91 and 78.28±4.38 for DRILL and PIEZO groups, respectively; p<0.05) and cancellous regions (9.62±4.06 and 19.94±14.18 for DRILL and PIEZO groups, respectively; p<0.05). The piezosurgery also showed higher PMT values in the cancellous zone (9.35±5.54 and 18.72±13.21 for DRILL and PIEZO groups, respectively; p<0.05). However, the DRILL group presented better results for BIC in cortical region (80.42±10.88 and 70.25±16.93 for DRILL and PIEZO groups, respectively; p<0.05). In conclusion, for the implant site preparation, the piezosurgery was beneficial to bone healing rates in the cancellous bone region, while the drill technique produced better results in the cortical bone.

Effectiveness of methods for detaching orthodontic implants likely to fracture upon rotational torque - an animal study

Orthodontic implants may fracture at the cortical bone level upon rotational torque. The impacted fragment can be detached by a range of methods, which are all more or less time-consuming and injurious to the cortical bone. The aim of this study was to compare three different methods for detaching an orthodontic implant impacted in cortical bone. Health Sciences University of Hokkaido animal ethics committee approved the study protocol. Orthodontic titanium-alloy (Ti-6Al-4 V) implants were placed bilaterally on the buccal side of the mandible of beagle dogs. Subsequently, the implants were detached using either a low-speed handpiece with a round bur, alternatively by use of a low-power or a high-power ultrasonic instrument. In the first experiment, 56 orthodontic implants were placed into the dissected mandible from 7 animals. The methods for detachment were compared with respect to time interval, as well as associated undesirable bone loss as appraised by use of cone-beam computed tomography. In experiment two, 2x2 implants were placed bilaterally in the mandible of 8 animals and subsequently detached by manual rotational torque, and the described three methods for detachment. The implant socket was investigated histologically as a function of removal method immediately after removal, and after 1, 3 and 8 weeks and contrasted with the healing of the socket of the implant that was detached by manual rotational torque. Statistical significance was appraised by the use of non-parametric Kruskal-Wallis one-way analysis of variance. The method using the low-power ultrasonic required significantly longer removal time versus the two other methods, i.e. high-power ultrasonic and low-speed handpiece with a round bur (p < 0.02). The amount of undesirable bone loss was substantially larger with low-speed handpiece with a round bur compared to the two ultrasonic methods (p < 0.05). Bone formation after 3 weeks of healing was more complete following the use of low or high-power ultrasonic instrument in comparison with a low-speed handpiece rotary instrument method. Orthodontic implants likely to fracture upon rotational torque or impacted fractured fragments should be detached preferably with an ultrasonic instrument, because of less associated bone loss and more rapid bone healing compared to the use of a low-speed handpiece rotary instrument.

Piezoelectric Bone Surgery: A Review of the Literature and Potential Applications in Veterinary Oromaxillofacial Surgery

Piezoelectric bone surgery is a recent and innovative technology, permitting a selective cut of mineralized tissue while sparing soft tissue. Similar to a dental scaler, a high frequency vibration, in the range of 25-35 kHz, is transmitted to a metallic tip. However, the power of the piezosurgical instrument is three to six times higher than that of a dental scaler. The major advantages of this technology include high precision, a design that increases ease of curvilinear osteotomy, less trauma to soft tissue, preservation of neurological and vascular structures, reduced hemorrhage, minimal thermal damage to the bone, as well as overall improvement of healing. The handpiece of the instrument is equipped with a sterile irrigation system and light-emitting diode (LED) light, which improves visibility and overall safety. Piezoelectric surgery is particularly useful when performing delicate bone procedures such as periodontal or endodontic surgery. It is also indicated when performing more invasive bone surgery such as maxillectomy, mandibulectomy, and condylectomy, where preservation of neurovascular structures is important. Piezoelectric instruments are different from rotary instrumentation or oscillating saws, they require light pressure with constant motion of the tip. Training is required to master the technique.

Intraoperative complications during sinus floor elevation using two different ultrasonic approaches: a two-center, randomized, controlled clinical trial

PURPOSE

The aim of this study was to assess the prevalence of intraoperative complications during maxillary sinus elevation with lateral approach using a piezoelectric device with two different surgical techniques.

MATERIALS AND METHODS

Antrostomies were randomly performed by outlining a window (group A, 36 patients) or by eroding the cortical wall with a grinding insert until the membrane was visible under a thin layer of bone, before outlining the window (group B, 36 patients). Occurrence of membrane perforation, laceration of vascular branches, and surgical time was recorded.

RESULTS

Seventy-two patients underwent sinus floor elevation: four perforations (11.1%) were observed in group A (two occurred during elevation with hand instruments) and zero perforations in group B (p < .05). No evidence of vascular lacerations was registered in both groups. A clinically insignificant but statistically shorter surgical time was recorded in group A (9.2 ± 3.7 minutes) than in group B (13.3 ± 2.4 minutes; p < .05).

CONCLUSIONS

Within the limits of the present study, it may be concluded that ultrasonic erosion of the lateral wall of the sinus is a more predictable technique than piezoelectric outlining of a bone window in preventing from accidental perforations of Schneiderian membrane during sinus augmentation procedures.

Latest trends in craniomaxillofacial surgical instrumentation

PURPOSE OF REVIEW

To review the past year's literature regarding recent innovations in surgical instrumentation for craniomaxillofacial surgery.

RECENT FINDINGS

Current advances in surgical instrumentation have led to many improvements in the field, allowing greater visualization and precision both before and during procedures. One of the common goals is to achieve excellent outcomes with minimal complications, while at the same time minimizing invasiveness of surgery. Highlighted innovations include greater capacities for acquisition of data, leading to improved imaging modalities and expansion of computer-assisted surgical techniques; continued developments in biomaterials used in various reconstructions; and novel uses of bone cutting and bone fixation instrumentation.

SUMMARY

Technology in the field of craniomaxillofacial surgery is developing rapidly, leading to novel instrumentation being utilized across a broad spectrum of areas. Published data have been encouraging to date, indicating an ever increasing adaptation of these innovations in clinical practice. Future efforts need to focus on cost-benefit analysis and constructing larger-scale studies to better understand effectiveness and patient outcomes.

Characterisation of bone following ultrasonic cutting

OBJECTIVES

Ultrasonic surgery is an increasingly popular technique for cutting bone, but little research has investigated how the ultrasonic tip oscillations may affect the cuts they produce in bone. The aim of this investigation was to evaluate the oscillation and cutting characteristics of an ultrasonic surgical device.

MATERIALS AND METHODS

A Piezosurgery 3 (Mectron, Carasco, Italy) ultrasonic cutting system was utilised with an OP3 style tip. The system was operated with the tip in contact with porcine bone samples (loads of 50 to 200 g) mounted at 45° to the vertical insert tip and with a water flow of 57 ml/min. Tip oscillation amplitude was determined using scanning laser vibrometry. Bone surfaces defects were characterised using laser profilometry and scanning electron microscopy.

RESULTS

A positive relationship was observed between the magnitude of tip oscillations and the dimensions of defects cut into the bone surface. Overloading the tip led to a reduction in oscillation and hence in the defect produced. A contact load of 150 g provided the greatest depth of cut. Defects produced in the bone came from two clear phases of cutting.

CONCLUSIONS

The structure of the bone was found to be an important factor in the cut characteristics following piezosurgery.

CLINICAL RELEVANCE

Cutting of bone with ultrasonics is influenced by the load applied and the setting used. Care must be used to prevent the tip from sliding over the bone at low loadings.