The Use of Patient-Specific Implants in Oral and Maxillofacial Surgery.

This article summarizes the current use of patient-specific implants in oral and maxillofacial surgery.

Is the piezoelectric device the new standard for facial osteotomies?

Piezoelectric devices are commonly used in all areas of maxillofacial surgery. Initially applied in preprosthetic surgery, they have steadily become a common practice in major surgery of the facial skeleton, including maxillary and mandibular osteotomies, temporomandibular joint surgery, orbital surgery, craniofacial procedures and rhinoplasty. We will review the current medical literature and establish the "state of the art" of piezosurgery in orthognathic surgery, TMJ surgery and rhinoplasty.

The use of patient-specific implants in orthognathic surgery: A series of 32 maxillary osteotomy patients.

The use of virtual surgery, patient-specific saw and drill guides, and custom-made osteosynthesis plates is rapidly spreading from deformity surgery to orthognathic surgery. Most of the commercially available systems are using computer-aided design/computer-aided manufacture (CAD/CAM) wafers to produce patient-specific saw guides. However, most plate systems provided are still the conventional "in stock" mini plates that can be individually designed by pre-bending according to the stereolithographic model of the patient. Custom made three-dimensional (3D) printed implants have earlier been demonstrated to be an ideal solution in deformity surgery and in reconstruction of complex posttraumatic cases. In this study, we report the novel use of patient-specific saw and drill guides combined with patient-specific 3D titanium alloy implants as a fixation system in maxillary movement after Le Fort I and bimaxillary osteotomies (n = 32). The implants were individually designed for each patient to follow anatomical structures and to provide exact positioning and stability of the repositioned maxilla.

Maxillary Segmental Micro Osteotomy: A Human Cadaver Study on the Efficacy of the Technique.

PURPOSE: Ultrasonic bone cutting was recently introduced as a feasible alternative to the conventional tools of cranio-maxillofacial surgery because it offers improved precision and safety.This study examined the feasibility of minimally invasive orthodontic or preprosthetic surgery using a piezosurgery device for latero-posterior maxillary segmental osteotomy. MATERIALS AND METHODS: Four fresh cadaveric heads were obtained for this study. Maxillary posterior osteotomy was performed using piezoelectric surgery. To preserve the vascular supply, only 1 vestibular incision was made during surgery. The Mectron Piezosurgery unit is a multipurpose device that uses micrometric ultrasonic piezoelectric vibrations with a variable frequency and cutting energy. The strategy for maxillary osteotomy included 1 horizontal osteotomy, 2 vertical osteotomies, and 1 palatal osteotomy performed transantrally without incision of the mucoperiosteum. The osteotomies were performed using a piezodevice (OT7-type inserts: 0.55 and 0.35 mm). In total, 1 horizontal cut (3 mm above the roots of the teeth), 2 vertical bone cuts, and 1 palatal osteotomy were made without incision of the palatal mucoperiosteum.Gentle dissection of the buccal fat pad was used to promote the healing of hard and soft tissues in the osteotomized zone. RESULTS: No damage to soft tissues, including the palatal mucosa, occurred. The buccal fat pad was mobilized easily without requiring an additional incision. The osteotomic sites were linear and clean in the palatal aspect. The integrity of the vascular network was maintained because of the lack of damage to the palatal mucosa. No chisels were used during the osteotomies. DISCUSSION: This cadaveric study shows the feasibility of using piezosurgery for segmental maxillary osteotomy. This report outlines a new and simple application of segmental maxillary micro-osteotomy.

Segmental Dento-alveolar Intrusive Osteotomy in Posterior Maxilla with Lack of Inter-arch Distance for Prosthetic Rehabilitation. A Technique Combined with Sinus Floor Elevation.

UNLABELLED: The aim of this paper is to present a technique for segmental dento-alveolar intrusive osteotomy in a posterior maxilla with lack of inter-arch distance for prosthetic rehabilitation combined with sinus floor elevation. METHODS: A full thickness flap is elevated exposing the lateral wall of the maxillary sinus. A lateral window is opened and the Schneiderian membrane elevated. Segmental dento-alveolar osteotomy is performed. After complete detachment of the segment, it is adapted and fixed to the new position using the pre-prepared guide, making sure not to damage or perforate the Schneiderian membrane. RESULTS: Four cases of segmental dento-alveolar intrusive osteotomy in a posterior maxilla combined with sinus floor elevation were performed utilizing the above-mentioned technique. All surgeries went according to plan, and healing was uneventful except for swelling and pain that lasted for 10-14 days post- operatively. The opposing dentition was later treated by implant placement. The average follow-up time for those cases was 5.4 months. Vitality test four months after surgery was positive. CONCLUSION: The presented technique for segmental dento-alveolar intrusive osteotomy combined with sinus floor elevation can serve as a viable treatment option in the posterior maxilla with lack of inter-arch distance due to severe overeruption.

Computer-aided design and computer-aided manufacturing cutting guides and customized titanium plates are useful in upper maxilla waferless repositioning.

PURPOSE: The purpose of the present study was to develop a computer-aided design (CAD) and computer-aided manufacturing (CAM) technique that enabled fabrication of surgical cutting guides and titanium fixation plates that would allow the upper maxilla to be repositioned correctly without a surgical splint in orthognathic patients. MATERIALS AND METHODS: Ten patients were recruited. A complete CAD-CAM workflow for orthognathic surgery has 3 steps: 1) virtual planning of the surgical treatment, 2) CAD-CAM and 3-dimensional printing of customized surgical devices (surgical cutting guide and titanium fixation plates), and 3) computer-aided surgery. Upper maxilla repositioning was performed in a waferless manner using a CAD-CAM device: the surgical cutting guide was used during surgery to pilot the osteotomy line that had been planned preoperatively at the computer and the custom-made fixation titanium plates allowed desired repositioning of the maxilla. RESULTS: To evaluate the reproducibility of this CAD-CAM orthognathic surgical method, the virtually planned and actually achieved positions of the upper maxilla were compared. Overlap errors using a threshold value smaller than 2 mm were evaluated, and the frequency of such errors was used as a measurement of accuracy. By this definition, the accuracy was 100% in 7 patients (range in all patients, 62 to 100%; median, 92.7%). CONCLUSION: These results tend to confirm that the use of CAD-CAM cutting guides and customized titanium plates for upper maxilla repositioning represents a promising method for the accurate reproduction of preoperative virtual planning without the use of surgical splints.

Mini-implant applications in orthognathic surgical treatment.

Orthognathic surgical treatment conventionally relies on the use of full arch fixed orthodontic appliances. However, the introduction of orthodontic mini-implants has altered surgical options in terms of providing an alternative to fixation (intermaxillary fixation, IMF) screws and even to maxillary osteotomy. This paper describes the integration of mini-implants within orthognathic treatments in terms of 'surgery first' treatments and by introducing the concept of the conversion of bimaxillary cases into mandible-only surgery treatments.

Using drill stops on twist drills to promote safety and efficiency when creating osteotomies for dental implants.

BACKGROUND: A growing number of dental implants are being placed each year in the United States. This upward trend is associated with an increased incidence of comorbidities. In this regard, use of a drill stop has the potential to decrease unintended consequences of overdrilling the depth of an osteotomy. METHODS: The authors did not find any studies in the dental literature in which researchers assessed the safety and effectiveness of using drill stops on twist drills. Nevertheless, the advantages of utilizing drill stops and the undesired results due to excessive drilling can be reasonably deduced. RESULTS: The authors describe the following clinically relevant issues pertaining to overdrilling of osteotomies for dental implants: the anatomical effect of excessive drilling in different sections of the oral cavity, reasons for excessive drilling, methods to avoid overlengthening of implant sites and benefits of using drill stops on twist drills. CONCLUSIONS: Use of drill stops enhances safety, accuracy and efficiency when creating an osteotomy. Drill stops also reduce the clinicians and patients stress during operative procedures. PRACTICAL IMPLICATIONS: Drills stops can be beneficial when utilized in situations in which there is reduced visibility, making it difficult to read the lines on a twist drill. They also are helpful when there is a dearth of bone over the mandibular or mental nerves, and precisely lengthened osteotomies are needed to avoid nerve injuries.

Digital model planning and computerized fabrication of orthognathic surgery wafers.

Conventional orthognathic wafers are made by a process involving manual movement of stone dental models and acrylic laboratory fabrication. In addition, a facebow record and semi-adjustable articulator system are required for maxillary osteotomy cases. This paper introduces a novel process of producing both intermediate and final orthognathic surgical wafers using a combination of computerized digital model simulation and three-dimensional print fabrication, without the need for either a facebow record or the additional ionizing radiation exposure associated with cone beam computerized tomography.

Comparison of a novel trephine drill with conventional rotary instruments for maxillary sinus floor elevation.

PURPOSE: The purpose of this study was to compare a newly designed trephine drill (SLA KIT, Neobiotech) with conventional rotary instruments for maxillary sinus floor elevation based on operative time, postoperative pain, and perforation rates. MATERIALS AND METHODS: Twenty-five patients were treated with a bilateral sinus floor elevation procedure with rotary trephine and conventional instruments. One side was treated with conventional rotary instruments, while the contralateral side was treated with rotary trephine instruments, with a 2-week gap between surgeries. Operative time was measured with a chronometer in seconds as the time from soft tissue incision to primary closure of the incision with the last suture. Pain was scored on a 10-point visual analog scale at 24 hours after surgery. The presence of tears and perforations was determined by direct visualization and the Valsalva maneuver. RESULTS: Twenty-five patients were included in the study. Operative time was shorter when the trephine drill was used (11.1 ± 2.4 minutes) than with conventional rotary instruments (15.1 ± 2.9 minutes). Sinus membrane perforation was observed in eight patients when conventional rotary instruments were used, while the trephine drill resulted in two sinus perforations. Mean pain scores were 2.01 ± 0.11 after using the trephine drill and 2.25 ± 0.76 when conventional rotary instruments were used. No significant difference was found in postoperative pain scores. CONCLUSION: The trephine drill technique may result in decreased perforation rates and operative time.

Lasers use in dental implantology.

OBJECTIVE: The purpose of this literature review was to evaluate the present use of different laser systems in implant dentistry. MATERIALS AND METHODS: A literature search of MEDLINE-PubMed for articles published, describing the use of lasers in implant dentistry, was performed and articles were critically reviewed by the investigators to determine the strength of evidence. RESULTS: The literature review reveals a limited number of randomized clinical trials with regard to laser use in dentistry. Although many case studies indicate extensive use of lasers and promising results in dental implantology, lasers may be used for uncovering submerged implants atraumatically to prevent crestal bone loss, recontouring periimplant soft tissues and sculpting emergence profile for prosthetic components, raising surgical flaps, osseous recontouring, and creating parabolic tissue architecture. Additionally, bone harvesting of block grafts, window preparation in sinus lift procedures, ridge splitting, and debridement of extraction sockets for immediate implant placement were described. CONCLUSIONS: Aside from the many benefits associated with the use of lasers in implant-related procedures, there are also risks to consider from the laser irradiation on the implant surface and the periimplant tissues. Therefore, an appropriate training on laser use is mandatory to increase the clinical outcome and to control the potential of complications.

Custom-made prefabricated titanium miniplates in Le Fort I osteotomies: principles, procedure and clinical insights.

This paper describes a new type of miniplate system that is designed and custom made during virtual surgery planning based on an individual patient's osteotomy. These miniplates are prefabricated with commercially pure porous titanium using direct metal laser sintering. The principles that guide the conception and production of this new miniplate are presented. The surgical procedure from the stage of virtual surgery planning until the final Le Fort I osteotomy and bone fixation are described using a case example.

Evaluation of surgically assisted rapid maxillary expansion with piezosurgery versus oscillating saw and chisel osteotomy - a randomized prospective trial.

BACKGROUND: Ultrasonic bone-cutting surgery has been introduced as a feasible alternative to the conventional sharp instruments used in craniomaxillofacial surgery because of its precision and safety. The piezosurgery medical device allows the efficient cutting of mineralized tissues with minimal trauma to soft tissues. Piezoelectric osteotome has found its role in surgically assisted rapid maxillary expansion (SARME), a procedure well established to correct transverse maxillary discrepancies. The advantages include minimal risk to critical anatomic structures. The purpose of this clinical comparative study (CIS 2007-237-M) was to present the advantages of the piezoelectric cut as a minimally invasive device in surgically assisted, rapid maxillary expansion by protecting the maxillary sinus mucosal lining. METHODS: Thirty patients (18 females and 12 males) at the age of 18 to 54 underwent a surgically assisted palatal expansion of the maxilla with a combined orthodontic and surgical approach. The patients were randomly divided into two separate treatment groups. While Group 1 received conventional surgery using an oscillating saw, Group 2 was treated with piezosurgery. The following parameters were examined: blood pressure, blood values, required medication, bleeding level in the maxillary sinus, duration of inpatient stay, duration of surgery and height of body temperature. RESULTS: The results displayed no statistically significant differences between the two groups regarding laboratory blood values and inpatient stay. The duration of surgery revealed a significant discrepancy. Deploying piezosurgery took the surgeon an average of 10 minutes longer than working with a conventional-saw technique. However, the observation of the bleeding level in the paranasal sinus presented a major and statistically significant advantage of piezosurgery: on average the bleeding level was one category above the one of the remaining patients. CONCLUSION: This method of piezoelectric surgery with all its advantages is going to replace many conventional operating procedures in oral and maxillofacial surgery. TRIAL REGISTRATION: CIS 2007-237-M.

Ultrasonic orthognathic surgery: enhancements to established osteotomies.

The use of a novel ultrasonic osteotome enabled the authors to modify well-established orthognathic osteotomies to more favourably address the anatomy. For this purpose, they utilized a powerful ultrasonic device with tissue-selective cutting characteristics that was originally developed for spinal osteotomies and nerve decompression (BoneScalpel™ by Misonix Inc., Farmingdale, NY, USA). Its straight ultrasonic blade was adapted for dual action, and a soft protective element was added. The product modifications and the related changes regarding maxillary and mandibular osteotomies are explained in detail. A series of 83 patients underwent orthognathic surgery with the BoneScalpel ultrasonic osteotome. All osteotomies within this study group were performed purely ultrasonically and without the auxiliary use of reciprocating saws or rotary burrs. The complications, alveolar nerve impairment and bad splits were assessed. To assess the quality of the lingual osteotomies and pterygomaxillary separation, three-dimensional scanning was performed on 30 patients. In conclusion, the BoneScalpel™ ultrasonic osteotome enabled improved control over orthognathic osteotomies and resulted in significant reductions in the occurrence of nerve impairment and bad splits.

"Twist technique" for pterygomaxillary dysjunction in minimally invasive Le Fort I osteotomy.

PURPOSE: To present a new technique for effective, rapid, and safe pterygomaxillary dysjunction in the context of a minimally invasive Le Fort I protocol and to provide the authors' preliminary experience. MATERIALS AND METHODS: In total, 1,297 consecutive patients underwent Le Fort I osteotomy as an isolated procedure or in combination with mandibular surgery. In all cases, the "twist technique" was used to downfracture the maxilla. This method achieves pterygomaxillary dysjunction using a frontal approach and a straight osteotome that is driven along the standard Le Fort I horizontal osteotomy toward the pterygomaxillary junction. Downfracture is achieved by inwardly rotating the osteotome fixed at the zygomatic buttress. RESULTS: The studied sample consisted of 820 women and 477 men (mean age, 28.4 years). Mean surgical time of the maxillary procedure was 44 minutes. Mean incision length was 2.8 cm. No significant neurovascular complications or clinically evident iatrogenic fractures occurred. Mean maxillary advancement was 5.5 mm (range, 2.0 to 14.0 mm). CONCLUSIONS: Compared with classic pterygomaxillary dysjunction, the twist technique uses a frontal approach and a straight osteotome. This technical modification requires a substantially smaller incision, achieves an immediate effective separation of the maxilla, and enables adequate visualization of the palatine neurovascular bundle. The authors' preliminary experience in 1,297 patients shows the technique's safety and efficacy.

Surgically assisted rapid maxillary expansion: feasibility of not releasing the nasal septum.

Surgically assisted rapid maxillary expansion (SARME) is commonly used to correct maxillary transverse deficiency. The aim of this study was to analyse the need for intraoperative liberation of the nasal septum during the procedure. SARME was performed in 25 patients by combining a lateral osteotomy with an inter-radicular maxillary osteotomy. The deviation of the nasal septum after SARME was evaluated by comparing measurements between radiologically defined landmarks on pre- and postoperative computed tomographic images. Two defined angles (angle I, between crista galli-symphysis mandibulae and crista galli-septum nasi; angle II, between maxillary plane and septum nasi) were measured based on four representative planes and septal movement was analysed. The mean changes in angles I (0.03° ± 0.78°) and II (0.25° ± 1.04°) did not differ significantly from zero (p=0.87 and p=0.24, respectively). Observed variations and displacements were considered to be acceptable because they were insignificant in every respect. Intranasal airway function was also examined pre- and postoperatively to evaluate any loss of ventilation. The described surgical technique is a successful method of maxillary segment distraction. The authors found no compelling reason to release the nasal septum in the context of SARME.

Maxillary advancement with conventional orthognathic surgery in patients with cleft lip and palate: is it a stable technique?

PURPOSE: To evaluate the long-term skeletal stability after maxillary surgical advancement with conventional Le Fort I osteotomy in patients with cleft lip and palate by a systematic review of the published data. MATERIALS AND METHODS: Electronic databases, "gray literature," and reference list searches were conducted. The inclusion criteria were the stability of maxillary surgical advancement with conventional Le Fort I osteotomy fixed with plates and assessed at the post-treatment follow-up 1 year or more postoperatively in patients with cleft lip and/or palate. Full reports were retrieved from abstracts or titles that appeared to meet the inclusion criteria or lacked sufficient detail for immediate exclusion. Once full reports were collected, they were again reviewed, considering more detailed inclusion criteria for a final selection decision. A methodologic quality assessment tool was used. The quantity and quality of the obtained data precluded a meta-analytic approach. RESULTS: A total of 25 abstracts/titles met the initial search criteria, and 10 studies were finally selected. The overall methodologic quality scores were high for only 1 randomized clinical trial. After maxillary advancement with Le Fort I in patients with cleft lip and palate, the long-term horizontal relapse at the A-point was 20% to 30% in 4 studies and 30% to 40% in 3 studies. In addition, vertical relapse was more than 50% in 4 studies. The study judged as a high-quality study reported a 37% rate of horizontal relapse and a 65% rate of vertical relapse at the A-point. CONCLUSIONS: Current evidence suggests maxillary surgical advancement with conventional Le Fort I osteotomy in patients with cleft lip and palate appears to show a moderate relapse rate in the horizontal plane and a high relapse rate in the vertical plane.