In comparison with conventional micro-saws and rotating cutting devices, devices that utilize ultrasonic vibration to cut bone are less invasive and are being used more frequently in clinical settings, and a number of research reports have been published. The objective of this study was to compare the cutting efficiency, cutting area and noise at the time of cutting for each of five different ultrasonic bone cutting devices.
Using costal bone from pigs with a cortical bone thickness of approximately 1.5 mm, we cut the bone using the Piezon Master Surgery (PMS), Piezosurgery3 (PS), Piezosurgery Touch (PST), Piezotome (PT), and Piezotome2 (PT2) to create a square cutting area measuring 1×1 cm (n = 40). Evaluation items included the time required for cutting, cutting area and noise at the time of cutting. Data were assessed using Levene's test, followed by variance analysis and multiple comparison testing. Spearman's correlation coefficient was used to identify correlations between each evaluation item.
Significant differences in the time required for cutting were observed for all of the devices other than between the PS and PT2, and the PST and PT2. The cutting time was shortest with the PST and increased in the order of PT2, PS, PT and PMS. Significant differences in the cutting area were observed for all of the devices other than between the PMS and PT, and the PS and PST. The cutting area was largest with the PMS and decreased sequentially in order of the PT, PS, PST and PT2. Significant differences in the cutting noise were observed for all of the devices other than between the PMS and PST, and the PS and PT2. The cutting noise was loudest with the PT2 and decreased sequentially in order of the PS, PMS, PST and PT. The results of correlation analysis showed a strong correlation between cutting time and cutting area.
A positive correlation was observed between the cutting time and cutting area, but the cutting times, cutting areas and cutting noise were different for each of the devices, suggesting that practitioners need to take these factors into consideration when selecting an ultrasonic bone cutting device.
In practice, it is often difficult to perform open reduction for the treatment of mandibular fracture with temporomandibular joint (TMJ) dislocation in a totally edentulous patient when the denture is not adjusted. In this study, the application of implant simulation software and guided surgery technique for fixing the denture was attempted for the treatment of mandibular fracture with TMJ dislocation in a totally severe atrophic edentulous patient, and resulted in successful treatment.
In January 2012, an 85-year-old man complaining of mouth closing disorder was referred to our clinic, because open reduction surgery of the mandible could not be successfully treated in the plastic surgery clinic of our hospital. Three-dimensional CT imaging revealed bilateral fracture of the mandible and unilateral anterior luxation of TMJ in the severe atrophic totally edentulous maxilla and mandible. His upper and lower dentures were unstable in the oral cavity.
Open reduction and intermaxillary fixation using the patient's own dentures were planned. However, his upper denture was unstable in the oral cavity and his upper jaw had insufficient bone volume to place intermaxillary fixation (IMF) screws. Therefore, proper positons and safety spaces for IMF screw placement were examined by using implant simulation software and guided surgery procedure. CT images were taken using the so-called double scanning technique and the IMF screw positions were analyzed using the implant simulation software (SimPlant®). Prior to the operation, drill guiding holes were manually drilled in the maxillary denture according to the simulation results. The hooks for intermaxillary fixation were attached to the upper and lower dentures.
In February 2012, open reduction surgery was performed under general anesthesia. After the manipulate reduction of TMJ, the maxillary denture was rigidly fixed using five IMF screw implants 10 or 12 mm in length without perforation into the maxillary sinuses. Following the circumferential wiring of the lower denture, the intermaxillary fixation was successfully done for proper occlusion. Rigid fixation of the fractured mandibula was performed using a titanium mandibular reconstructive plate. Postoperatively, there was no evidence of TMJ redislocation.
The present case suggests that, in severe atrophic totally edentulous patients, the application of implant simulation software and guided surgery technique for fixing the denture is an effective strategy for the treatment of mandibular fracture with TMJ dislocation and the prevention of reluxation of TMJ.
The purpose of this study was to evaluate the risk factors for the loss of implants with sinus floor elevation. We statistically carried out a clinical examination on 49 cases, 80 implants at 3 years after the fitting of implant-anchored fixed prostheses.
The results are summarized as follows:
1. Two implants failed in 80 implants, indicating survival rates of 97.5%.
2. There was no statistically significant difference between implant placement timing, initial bone height, sinus membrane thickness, type, diameter, primary stability of implants and graft materials used for sinus floor elevation.
3. The length of implant affected the survival of implants used for sinus floor elevation.
In 2013, we formed the Nagano-ken Dental Implant Network (NDIN) for constructing a system of cooperation between hospitals and clinics in dental implant treatment. In this study, we conducted a retrospective review of the patients who underwent dental implant treatment in the network hospitals and investigated the effects of the NDIN. Ten hospitals participated in the NDIN. From 2006 to 2014, 2,124 patients underwent dental implant treatment in the network hospitals. Of these, 1,502 (70.2%) were treated under the hospital and clinic cooperation. The rate of such cooperation had increased since the formation of the NDIN. The cooperation included 833 (55.5%) cases of first-stage surgery and/or second-stage surgery, followed by 489 (32.6%) cases of total implant treatment to setting the superstructure, 80 (5.3%) cases of consultation, 54 (3.6%) cases of management of complications, and 34 (2.3%) cases of imaging diagnosis with computed tomography scan. After forming the NDIN, the proportion of requests for total implant treatment had increased.