[Category of facial symmetry perception after maxillary reconstruction using anterolateral thigh flap].

OBJECTIVE: To preliminarily establish a category of facial symmetry perception after maxillary reconstruction using anterolateral thigh flap (ALTF) by the methods of stereophotogrammetry and subjective assessment. METHODS: The patients underwent maxillectomy due to neoplasms invasion, and all the maxillary defects were reconstructed using ALTF.Three-dimensional (3D) photographs were captured from the patients with a stereophotogrammatrical camera set-up.In the Geomagic software, the mirror image was created by reflecting along an arbitrary plane outside of the face.After the registration, the postoperative side on the original 3D photograph was segmented into 6 areas.The 3D change of the facial soft-tissue was measured using surface-based color map.Twenty laypeople took part in the study as observers, and they were asked to rate the 3D photographs using 5 point Likert-type scale according to their own aesthetic standard.The soft tissue asymmetry was graded according to the score.The collected data were subjected to statistical analysis using the SPSS 24.0 software. RESULTS: In the study, 44 subjects were recruited (21 males and 23 females, age range from 19 to 79 years).The soft-tissue symmetry was graded into three levels according to the subjective scores.The grade Ⅰ was basically symmetrical.The grade Ⅱ was slightly asymmetrical.The grade Ⅲ was obviously asymmetrical.Statistically significant differences were found in the suborbital (P < 0.05) and zygomatic (P < 0.05) areas when comparing all grades of soft-tissue asymmetry, and in the buccal (P < 0.05) and superiolabial (P < 0.05) areas when comparing grades Ⅰ and Ⅲ.The extent of maxillary defect had significant impact on the symmetry of the midface soft-tissue after maxillary reconstruction. CONCLUSION: Varying extent maxillectomy would result in varying degrees of asymmetry, and cause different grades of symmetry perception even if they had been reconstructed using ALTF.The higher the grade, the worse the symmetry of facial soft-tissue.Suborbital and zygomatic areas were important aesthetic units that affected the facial symmetry perception, followed by buccal and superiolabial areas.The clinicians should pay attention to the soft-tissue support in these areas when reconstructing the maxillary defect, especially large defect with orbital floor involved.

Simplified Zygomatic Implant Perforated (Zip) Flap for Rehabilitation in Low Level Maxillary Defects.

Rehabilitation in Low level maxillectomy cases has plethora of options right from local flaps to microvascular flaps. Subsequent to flap surgery, a maxillary dental rehabilitation can be demanding and a fixed or removable prosthesis is obligatory to provide them with near-normal function and aesthetics. Unlike the original ZIP flaps which were dedicated to microvascular flaps, we present here our unique experience with ZIP-Temporalis flap specifically for rehabilitation for patients of CAM (covid associated mucormycosis), its methods, advantages and limitations.

Development and Comparison of Conventional and 3D-Printed Laboratory Models of Maxillary Defects.

BACKGROUND: Recording accurate impressions from maxillary defects is a critical and challenging stage in the prosthetic rehabilitation of patients following maxillectomy surgery. The aim of this study was to develop and optimize conventional and 3D-printed laboratory models of maxillary defects and to compare conventional and digital impression techniques using these models. METHODS: Six different types of maxillary defect models were fabricated. A central palatal defect model was used to compare conventional silicon impressions with digital intra-oral scanning in terms of dimensional accuracy and total time taken to record the defect and produce a laboratory analogue. RESULTS: Digital workflow produced different results than the conventional technique in terms of defect size measurements which were statistically significant (p < 0.05). The time taken to record the arch and the defect using an intra-oral scanner was significantly less compared with the traditional impression method. However, there was no statistically significant difference between the two techniques in terms of the total time taken to fabricate a maxillary central defect model (p > 0.05). CONCLUSIONS: The laboratory models of different maxillary defects developed in this study have the potential to be used to compare conventional and digital workflow in prosthetic treatment procedures.

Bone remodeling of the sinus floor observed 19 years after third molar transplantation to close a maxillary defect: a case report.

Autologous tooth transplantation is the transplantation of an erupted, partially erupted, or unerupted tooth from one site to another in an individual. This is expected to maintain alveolar bone volume through physiological stimulation of the periodontal ligament (PDL). Tooth transplantation can be used for the closure of oroantral communication. As a simple, useful, and minimally invasive method, it should be considered a surgical option when a donor tooth is available in indicated cases. Herein, the authors report the case of a 20-year-old female patient whose left permanent maxillary first molar had to be extracted due to a longitudinal fracture and radicular cyst in the maxillary sinus floor. After the extraction, tooth 28 was exposed through an osteotomy and positioned in the gap. Nineteen years later, the autologous grafted tooth 28 could no longer be retained due to massive external resorption and was replaced by an implant. Human PDL stem cells can differentiate into bone-, fiber-, and cementum-forming cells and have the potential to build a PDL complex. Therefore, care must be taken to avoid damaging the PDL of the donor tooth during extraction. Autotransplanted teeth are expected to retain the alveolar bone volume. This case demonstrates the use of a transplanted tooth 28 for the treatment of a maxillary defect caused by the extraction of tooth 26 and removal of a radicular cyst. External resorption and regeneration of the bone of the maxillary sinus floor around the transplanted tooth occurred after 19 years.

Evaluation of surgical techniques in survival rate and complications of zygomatic implants for the rehabilitation of the atrophic edentulous maxilla: a systematic review.

PURPOSE: To assess the outcome [zygomatic implant (ZI) survival] and complications of the original surgical technique (OST) and an Anatomy-Guided approach (AGA) in the placement of ZI in patients with severely atrophic maxillae. METHODS: Two independent reviewers conducted an electronic literature search from January 2000 to August 2022. The inclusion criteria were articles reporting at least five patients with severely atrophic edentulous maxilla undergoing placement OST and/or AGA, with a minimum of 6 months of follow-up. Number of patients, defect characteristics, number of ZI, implant details, surgical technique, survival rate, loading protocol, prosthetic rehabilitation, complications, and follow-up period were compared. RESULTS: Twenty-four studies comprised 2194 ZI in 918 patients with 41 failures. The ZI survival rate was 90.3-100% in OST and 90.4-100% in AGA. Probability of complications with ZI with OST was as follows: sinusitis, 9.53%; soft tissue infection, 7.50%; paresthesia, 10.78%; oroantral fistulas, 4.58%; and direct surgical complication, 6.91%. With AGA, the presenting complications were as follows: sinusitis, 4.39%; soft tissue infection, 4.35%; paresthesia, 0.55%; oroantral fistulas, 1.71%; and direct surgical complication, 1.60%. The prevalence of immediate loading protocol was 22.3% in OST and 89.6% in the AGA. Due to the heterogeneity of studies, statistical comparison was only possible after the descriptive analysis. CONCLUSIONS: Based on the current systematic review, placing ZI in severely atrophic edentulous maxillae rehabilitation with the OST and AGA is associated with a high implant survival rate and surgical complications within a minimum of 6 months follow-up. Complications, including sinusitis and soft tissue infection around the implant, are the most common. The utilization of immediate loading protocol is more observed in AGA than in OST.

Reconstruction of nasal airway in patients of class IIId maxillary defect with vastus lateralis muscle-chimeric double skin paddle ALT flap.

BACKGROUND: A reconstructive challenge in patients with class IIId maxillary defect is how to obliterate the defect and restore a patent nasal airway. The current strategy using the single anterolateral thigh (ALT) fasciocutaneous flap for reconstruction may result in permanent mouth breathing. As the ALT flap was a common option in reconstruction processes, this study aimed to evaluate the benefits of vastus lateralis (VL) muscle-chimeric double skin paddle ALT flap in simultaneous defect and nasal airway reconstruction. METHODS: This study included 21 patients with class IIId maxillary defect who underwent free ALT flap reconstruction (n = 11, single ALT flap group; n = 10, VL muscle-chimeric double skin paddle ALT flap (chimeric ALT flap) group) at the China Medical University Hospital from August 2015 to September 2019. Associated parameters collected for analysis included gender, age, body mass index (BMI), operative time, hospitalization, clinical stage, preoperative treatment, flap/defect size, comorbidities, postoperative RT, mouth breathing and short/long term complications. RESULTS: No significant differences were observed in age, BMI, hospitalization, clinical stage, preoperative treatment, defect size, comorbidities, and postoperative RT between the two groups; however, the chimeric ALT flap group as dominated by male patients (p = 0.009), and had longer operative times (12.1 h vs. 10.1 h, p = 0.002) and larger flap sizes (180 cm2 vs. 96.7 cm2, p = 0.013). Compared with the chimeric ALT flap group, the single ALT flap group suffered from permanent mouth breathing. CONCLUSION: Nasal airway reconstruction should be considered in patients with class IIId maxillary defect. Compared to the single ALT flap, the chimeric ALT flap is a superior reconstructive option for patients with class IIId maxillary defect, although a longer surgical duration and larger flap size are required.

Zygomatic implant-supported prosthetic rehabilitation of a patient with Brown et al. Class II c maxillary defect: A clinical report.

The genesis of acquired maxillary defects poses a significant challenge when it comes to rehabilitating a patient prosthetically. These defects lead to functional and esthetic impairment, affecting the quality of life of an individual. This clinical report describes a satisfactory zygomatic implant-supported overdenture rehabilitation of a patient who underwent subtotal bilateral maxillectomy after an industrial accident. The result shows zygomatic implant-supported overdenture as a viable, predictable, and economical treatment option for a patient with an extensive maxillary defect.

Aesthetic reconstruction of onco-surgical maxillary defects using free scapular flap with and without CAD/CAM customized osteotomy guide.

BACKGROUND: Reconstruction of the maxillary defects following tumor ablation remains to be a challenge for surgeons. Virtual surgical planning (VSP), intraoperative cutting guides and stereolithographic models provides the head and neck reconstructive surgeon with powerful tools for complex reconstruction planning. Despite its use in fibular osteocutaneous reconstruction, application to the scapular free flap has not been as widely reported. The aim of this study was to compare aesthetic results and operation time of free scapular flap, with and without computer-aided design and computer-aided manufacturing (CAD/CAM) customized osteotomy guide, for reconstruction of maxillary defects. METHODS: In this prospective randomized controlled clinical trial study, we randomly assigned 22 patients with maxillary defects who were scheduled to undergo maxillary reconstruction with either free scapular flap with CAD/CAM customized osteotomy guide; study group (n = 11) or free scapular flap without CAD/CAM customized osteotomy guide; control group (n = 11). All patients were followed up for 3 months. The aesthetic outcome, operation and ischemic times were evaluated and compared. RESULTS: Aesthetic outcomes were evaluated objectively by means of differential surface area (sagittal and axial) measurement, which showed improved aesthetic outcome (contour symmetry) in the study group with a mean of (241.39 ± 113.74 mm2), compared to patients in control group with a mean of (358.70 ± 143.99 mm2). There were significant differences between the two groups (P < 0.05). Aesthetic outcomes were also evaluated subjectively by means of visual analogue scale (VAS) and patient's satisfaction score (PSS). The postoperative aesthetic appearance was better in the study group with more patients satisfied than that in control group and there were statistically significant differences (P = 0.039). The mean total operative time was 678.81 min and 777.18 min in the study group and control group respectively (P < 0.05) and the mean ischemia time was 133.18 min and 195.72 min for study group and control group respectively (P < 0.05). The ischemia time and total operative time were shorter in the study group compared to those in the control group and there were no flap losses in both groups. CONCLUSION: The use of CAD/CAM prefabricated cutting guides facilitates scapular flap molding and placement, minimizes ischemic time and operating time as well as improves aesthetic outcomes. Trial registration This trial was registered at ClinicalTrials.gov. REGISTRATION NUMBER: NCT03757286. Registration date: 28/11/2018.

Clinical Application of 3D-Printed Patient-Specific Polycaprolactone/Beta Tricalcium Phosphate Scaffold for Complex Zygomatico-Maxillary Defects.

(1) Background: In the present study, we evaluated the efficacy of a 3D-printed, patient-specific polycaprolactone/beta tricalcium phosphate (PCL/ß-TCP) scaffold in the treatment of complex zygomatico-maxillary defects. (2) Methods: We evaluated eight patients who underwent immediate or delayed maxillary reconstruction with patient-specific PCL implants between December 2019 and June 2021. The efficacy of these techniques was assessed using the volume and density analysis of computed tomography data obtained before surgery and six months after surgery. (3) Results: Patients underwent maxillary reconstruction with the 3D-printed PCL/ß-TCP scaffold based on various reconstructive techniques, including bone graft, fasciocutaneous free flaps, and fat graft. In the volume analysis, satisfactory volume conformity was achieved between the preoperative simulation and actual implant volume with a mean volume conformity of 79.71%, ranging from 70.89% to 86.31%. The ratio of de novo bone formation to total implant volume (bone volume fraction) was satisfactory with a mean bone fraction volume of 23.34%, ranging from 7.81% to 66.21%. Mean tissue density in the region of interest was 188.84 HU, ranging from 151.48 HU to 291.74 HU. (4) Conclusions: The combined use of the PCL/ß-TCP scaffold with virtual surgical simulation and 3D printing techniques may replace traditional non-absorbable implants in the future owing to its accuracy and biocompatible properties.

A New Strategy for Patient-Specific Implant-Borne Dental Rehabilitation in Patients With Extended Maxillary Defects.

PURPOSE OF THE STUDY: Patients undergoing ablative tumor surgery of the midface are faced with functional and esthetic issues. Various reconstructive strategies, such as implant-borne obturator prostheses or microvascular tissue transfer, are currently available for dental rehabilitation. The present study shows the first follow-up of patients treated with patient-specific implants (IPS Implants® Preprosthetic) for the rehabilitation of extended maxillary defects following ablative surgery. PATIENTS AND METHODS: All patients treated with patient specific implants due to postablative maxillary defects were included. 20 implants were placed in the 19 patients (bilateral implants were placed in one of the cases). In 65.75% of the cases, resection was performed due to squamous cell carcinoma. In addition to the primary stability, the clinical implant stability, soft tissue management, successful prosthodontic restoration, and complications were evaluated at a mean follow-up period of 26 months. RESULTS: All patient-specific implants showed primary stability and were clinically stable throughout the observation period. Definitive prosthodontic restorations were performed in all patients. No implant loosening was observed. Major complications occurred only in previously irradiated patients with insufficient soft tissue conditions (p = 0.058). Minor complications such as exposure of the underlying framework or mucositis were observed, but they never led to failure of restorations or implant loss. CONCLUSIONS: Treatment of postablative maxillary defects with patient-specific implants offers a safe alternative with predictable results for full and rapid dental rehabilitation, avoiding time-consuming augmentation procedures and additional donor-site morbidity.

Aesthetical and Accuracy Outcomes of Reconstruction of Maxillary Defect by 3D Virtual Surgical Planning.

BACKGROUND: Reconstruction of maxillary defect resulting from trauma or oncology surgery is of great importance for patients with physical and psychological complications. The virtual surgical planning (VSP) and 3D printing technics had been used in recent years which simplified the surgical procedure and promoted success and accuracy. To assess the accuracy and outcome of VSP surgery, here we report our experience in maxillary reconstruction retrospectively. METHOD: Patients who received maxillary defect reconstruction from 2013 to 2020 were analyzed retrospectively. These patients were divided into two groups. Group 1 received VSP and 3D printed guiding plates in the surgery, while group 2 underwent free-hand surgery (FHS). Patients with different vertical and horizontal defects were classified according to Brown and Shaw classification. Clinical information and postoperative complications of all patients were collected. For patients with unilateral maxillary defect, orbit volume, orbit height, and the contour of the reconstructed side were compared with the normal side. RESULT: Thirty-four patients who achieved the criteria were analyzed, of which 20 patients underwent VSP surgery. There were primary and secondary reconstruction cases in both two groups. Vascularized iliac crest flap was used in three cases, and fibula flap was performed in the other cases. One flap collapse occurred in FHS group. Seven patients in VSP group received dental implants, while the number in FHS group was 0. In vertical class III cases, the differences in orbit height (ΔD) and orbit volume (ΔV) between normal side and reconstructed side were measured and compared in the two groups. The mean ΔD is 1.78 ± 1.33 mm in VSP group and 4.25 ± 0.95 mm in FHS group, while the mean ΔV is 2.04 ± 0.85 cm3 in VSP group and 3.25 ± 0.17 cm3 in FHS group. The alterations of orbit height and volume in VSP group were much smaller than that in FHS group with statistical significance. From the perspective of aesthetics, the color-gradient map indicates a more symmetric and smoother curve of post-operation appearance in VSP group. CONCLUSION: Compared with traditional free-hand surgical technics, VSP and 3D printing guiding plates can allow for a more accurate maxillary reconstruction with improved aesthetics.

Temporalis Muscle Flap for the Immediate Reconstruction of Oral Defects after Oncologic Resection.

An oral defect after oncologic resection, especially in the upper jaw, is an extremely complex problem in terms of reconstructive surgery. Herein, we report 2 patients who were diagnosed with oral mucosal squamous cell carcinoma. In one patient, the lesion was present on the right side of the hard palate, invading the maxillary bone. In the other patient, the lesion was present in the left retromolar trigone region. Reconstruction of the postsurgical defects was successfully done using a temporalis muscle flap. Both patients were discharged after ensuring the absence of any postsurgical complications. Furthermore, the postoperative functional and esthetic outcomes were adequate. These case reports highlight the usefulness and reliability of a temporalis muscle flap for the immediate reconstruction of oral and maxillary defects after oncologic resection.

Staged reconstruction of hemimaxillectomy defect: Application of buccal fat pad flap, iliac bone graft and implant-supported dental prostheses.

In order to achieve a fixed implant-supported prosthesis in a posthemimaxilectomy patient, ideal soft and hard tissue rehabilitation is necessary. Here, we present a staged approach for soft tissue reconstruction with local flaps followed by anterior iliac crest bone graft which resulted in a predictable and satisfactory outcome.

Prosthetic Rehabilitation of a Maxillary Defect Caused by Ameloblastoma of Rare Occurrence: A Clinical Case Report.

According to WHO statistics, individuals of the Indian subcontinent have the highest prevalence of orofacial cancer. Surgery, radiation, chemotherapy, or combination therapies are commonly administered treatment modalities for the treatment of oral cancer. Rehabilitation after surgical resection of the maxillary area is often a challenging task for maxillofacial prosthodontists. The size and location of the defect usually influence the amount of impairment and difficulty in prosthetic rehabilitation. Communication between nasal and oral cavities causes difficulty in swallowing and speech and gives unesthetic appearance. Obturator prosthesis is commonly used as an effective means for rehabilitating hemimaxillectomy cases. This article presents a case of acquired maxillary defect due to ameloblastoma with unfavorable undercuts, which was successfully treated by an immediate obturator following surgical resection and followed by a one-piece closed hollow bulb obturator, by utilizing the remaining palate and dentition to maximize the support, stability, and retention, which acts as a barrier to the communication between the oral and nasal cavities.

[Postoperative position change of fibular bone after reconstruction of maxillary defect using free fibular flap].

OBJECTIVE: To investigate the position change of the fibular bone after maxillary reconstruction by free fibular flap and to analyze the factors affecting the position change. METHODS: Patients who underwent maxillary reconstruction by free fibular flap in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from November 2012 to November 2016 were enrolled in this study. CT scans 1 week and 1 year postoperatively were collected and stored in DICOM format. The ProPlan CMF software was used to reconstruct the CT scans and separate the maxilla and each segment of the fibular flap. The Geomagic Control software was used to measure the long axis direction vector of each fibular segment. And the position change direction was recorded. The patients were divided into groups according to the use of the fibula or titanium plate to reconstruct the zygomaticmaxillary buttress. RESULTS: A total of 32 patients were enrolled. Among them, 21 were in the titanium plate group and 11 in the fibula bone group. The angle between the long axis of the fibular segment and the X axis in the X-Y plane was 95.65°±53.49° and 95.53°±52.77°, 1 week and 1 year postoperatively, and there was no statistical difference (P>0.05). The angle between the long axis of the fibular segment and the X axis in the X-Z plane was 96.88°±69.76° and 95.33°±67.42°, respectively, with statistical difference (P=0.0497). The angular changes of the long axis of the fibular segment in the titanium plate group and the fibular bone group were 3.23°±3.93° and 1.94°±1.78°, respectively, and the angular changes in the X-Z plane were 6.02°±9.89° and 3.27°±2.31°, respectively. There was no significant difference between the groups (P>0.05). The long axis changes of the fibular segment in the X-Y plane for reconstruction of the anterior alveolar, posterior alveolar, and buttress were 3.13°±3.78°, 2.56°±3.17°, and 5.51°±4.39°, respectively. There was a statistical difference (P = 0.023) between the posterior and buttress. In the X-Z plane, theses were 4.94°±4.75°, 5.26°±10.25°, 6.69°±6.52°, respectively. There was no statistical difference among the three groups (P>0.05). The main positional deviation directions of the titanium plate group and the fibular bone group were interior and superior sides, and there was no statistical difference between the two groups (P>0.05). CONCLUSION: One year postoperatively, the position of the free fibular flap was changed compared with 1 week postoperatively. The position of the free fibular flap was mainly changed to the interior and superior sides.

Invasive maxillary aspergillosis in a patient with systemic lupus erythematosus: Case report.

INTRODUCTION: Invasive aspergillosis (IA) is a fungal infection caused by Aspergillus species (spp.). Aspergillosis is the most common source of opportunistic fungal infection in humans. IA can cause serious complications related to high morbidity and mortality in immunocompromised patients. PRESENTATION OF CASE: We report a case of a 22-year-old female with a chief complaint of having a hole in the roof of her mouth. She was diagnosed with SLE in 2009. She had been consuming oral methylprednisolone ever since. In 2018, she experienced worsened symptoms and was hospitalized. She experienced swelling and bleeding of her gums and some of her teeth becoming loose and falling out, and then developing a hole in the roof of her mouth. Subsequently, she was treated with oral cyclophosphamide, oral mycophenolate sodium, and oral fluconazole. She was asked to stop taking oral methylprednisolone. In 2019, the palate biopsy was performed and showed Aspergillus spp. invading the palate. Afterward, the patient was referred to our clinic for defect closure. The patient was operated on for debridement and reconstruction of the defect. There was no recurrence of the defect or complications observed in the follow-up. The patient was satisfied with the surgical results. DISCUSSION: IA is a destructive and potentially harmful opportunistic fungal infection and treatments with surgical interventions should be well-thought-out in immunocompromised patients. CONCLUSION: The management of IA are controlling any underlying diseases and surgical debridement or necrotomy. Generally, antifungal therapy and prompt surgical intervention are successful in managing invasive aspergillosis.

Mastication in maxillectomy patients: A comparison between reconstructed maxillae and implant supported obturators: A cross-sectional study.

OBJECTIVE: The aim of this study was to compare masticatory performance and patient reported eating ability of maxillectomy patients with implant-supported obturators and patients with surgically reconstructed maxillae. METHODS: This cross-sectional study was conducted at the University of Alberta, Edmonton, Canada and at Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands. Eleven surgically reconstructed maxillectomy patients have been included at University of Alberta and nine implant-supported obturator patients at MUMC+. The mixing ability test (MAT) was used to measure masticatory performance. In addition, the oral health related quality of life (OHRQoL) was measured with shortened versions of the oral health impact profile (OHIP) questionnaire. Values of the implant-supported obturator group versus the surgical reconstruction group were compared with independent t-tests in case of normal distribution, otherwise the Mann-Whitney U test was applied. RESULTS: Patients with reconstructed maxillae and patients with implant-supported obturator prostheses had similar mean mixing ability indices (18.20 ± 2.38 resp. 18.66 ± 1.37; P = .614). The seven OHRQoL questions also showed no differences in masticatory ability between the two groups. CONCLUSION: With caution, the results of this study seem to confirm earlier results that implant-supported obturation is a good alternative to surgical reconstruction for all Class II maxillary defects. With both techniques, the masticatory performance is sufficiently restored, with careful planning being highly desirable.

Definitive maxillary obturator prosthesis: Timelines for fabrication and follow-up.

INTRODUCTION: A definitive maxillary obturator prosthesis can be used to rehabilitate a maxillary defect with the aim of improving speech, deglutition, and elimination of oronasal regurgitation. The aims of this study were (1) to determine the time required to fabricate a definitive maxillary obturator prosthesis and (2) to compare the fabrication and follow-up times between a patient's first and second definitive maxillary obturator prosthesis. MATERIALS AND METHODS: A retrospective review was completed of patients that had maxillary definitive obturators fabricated following head and neck surgery from 2002 to 2018 (n = 173). Demographics, clinical data, date of surgery, start date of fabrication, follow-up dates, and prosthesis follow-up data were collected. RESULTS: The median time to delivery of the patient's first definitive maxillary obturator prosthesis from the date of surgery was 7.7 months for nonradiated patients and 9.6 months for radiated patients (P ≤ .05). Additionally, there was a significant difference in the median number of appointments to fabricate the 1st definitive maxillary obturator prosthesis as compared to the 2nd prosthesis (6 vs 5; P ≤ .05). CONCLUSION: Fabrication timelines differed based on history of radiotherapy and patient experience. This data is helpful to set expectations for patients and practitioners regarding the process for prosthesis fabrication and follow-up.

[Application of 3D computer-assisted printing technique combined with plastic titanium mesh in the reconstruction of maxillary defect].

Objective: To investigate the application and clinical outcomes of using 3D computer-assisted printing technique combined with plastic titanium mesh in the reconstruction of maxillary defect. Methods: Clinical data of 14 patients in Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Ninth People's Hospital from January 2016 to June 2018, who were treated for partial or total removal of the maxilla due to benign or malignant tumors and those acquired maxillary defects caused by severe compound trauma were analyzed retrospectively. Twelve males and 2 females were included, with the age ranging from 16 to 51 years old. The sinonasal malignant tumors included squamous carcinoma (n=2) while benign tumors included hemangioma (n=1), maxillary fibrous dysplasia (n=3), maxillary cyst (n=2) and giant cell tumor of the maxilla (n=1). Five cases of post-traumatic maxillary defect were also included. According to preoperative thin-layer CT scanning data, computer modeling data was transmitted to a 3D printer to print out the original model and the reconstructed model. Preoperative simulation of tumor removal and maxillary reconstruction was done on the patient's original model, and the titanium mesh was shaped on the reconstructed model in order to properly reconstruct the area needed to be repaired. The pre-made titanium mesh was implanted into the defect area, the soft tissue flaps were reset, layered stitching and the local pressured bandage were used after surgery. Through postoperative clinical and CT examination, the patient's maxillofacial shape, nasal function and complications were evaluated. The results were analyzed by descriptive statistical method. Results: Lesions could be completely removed within the predicted range on the preoperative 3D-printed models of all cases. After debridement, titanium mesh could be implanted easily without re-shaping and trimming during surgery as in trauma cases. Titanium mesh could completely cover the missing bone surface closely, with titanium nails fixed smoothly, and the implanted titanium mesh was solid and stable. After the follow-up of 6 to 20 months, all patients were satisfied with the facial symmetry and the function was recovered well. Conclusion: Using 3D computer-assisted printing technique combined with plastic titanium mesh in the reconstruction of maxillary defect can accurately restore the maxillary structure for soft tissue support, and restore the facial shape and function.