Accuracy of digital surgical guides for dental implants / 대한악안면성형재건외과학회지

Background@#Recently developed imaging techniques, such as cone beam computed tomography (CBCT) and CAD/CAM technology, have facilitated reliable implant planning and implant surgical guide production by 3D printing. This study compared the accuracy of implant-guided surgery using the R2GATE® program with CBCT before and after surgery. @*Patients and methods@#The study included patients who visited the Department of Oral and Maxillofacial Surgery at Chonnam National University Hospital from September 2021 to March 2022. Twenty-four implants were placed in eleven patients. Using R2GATE® Windows (Megagen implant, Daegu, Korea) software, implant placement was planned. The difference was measured by the CBCT before and after surgery. The cervical and apical distance and angular deviation of the implants were measured. Statistical analysis was performed using an independent t-test, Pearson correlation, and multiple regression analyses. @*Results@#The three-dimensional linear distance difference between the planned implant and the placed implant was 0.97 ± 0.37 mm at the cervical and 1.13 ± 0.36 mm at the apical. The difference in angle deviation between the planned implant and the placed implant was 3.42 ± 2.12°. Among the variables affecting the accuracy of implant placement, a statistically significant difference was found when using a tissue-supported implant guide, implant diameter and implant length. @*Conclusion@#Based on these results, using the R2GATE® program is useful to use an implant digital surgical guide, and it will be used in various clinic.

Efficacy and safety of rhBMP/β-TCP in alveolar ridge preservation: a multicenter, randomized, open-label, comparative, investigator-blinded clinical trial / 대한악안면성형재건외과학회지

Background@#The aim of this multicenter, randomized, open-label, comparative, investigator-blinded study was to investigate the efficacy and safety of recombinant human bone morphogenetic protein 2 (rhBMP-2) combined with β-TCP (rhBMP-2/β-TCP) in alveolar ridge preservation. @*Materials and methods@#Eighty-four subjects from three centers were enrolled in this clinical trial. After tooth extraction, rhBMP-2/β-TCP (n = 41, test group) or β-TCP (n = 43, control group) were grafted to the extraction socket with an absorbable barrier membrane for alveolar ridge preservation. Using computed tomography images obtained immediately after and 12 weeks after surgery, changes in the alveolar bone height and width were analyzed for each group and compared between the two groups. @*Results@#Both the test and control groups showed a significant decrease in alveolar bone height in the 12 weeks after surgery (both groups, p < 0.0001). However, the test group exhibited a significantly lower decrease in alveolar bone height than the control group (p = 0.0004). Alveolar bone width also showed significantly less resorption in the test group than in the control group for all extraction socket levels (ESL) (p = 0.0152 for 75% ESL; p < 0.0001 for 50% ESL; p < 0.0001 for 25% ESL). There were no statistically significant differences in the incidence of adverse events between the two groups. No severe adverse events occurred in either group. @*Conclusions@#The results of this study suggest that rhBMP-2/β-TCP is a safe graft material that provides a high alveolar bone preservation effect in patients receiving dental extraction.

Reconstruction of the orbital wall using superior orbital rim osteotomy in a patient with a superior orbital wall fracture / 대한악안면성형재건외과학회지

BACKGROUND: Fractures of the orbital wall are mainly caused by traffic accidents, assaults, and falls and generally occur in men aged between 20 and 40 years. Complications that may occur after an orbital fracture include diplopia and decreased visual acuity due to changes in orbital volume, ocular depression due to changes in orbital floor height, and exophthalmos. If surgery is delayed too long, tissue adhesion will occur, making it difficult to improve ophthalmologic symptoms. Thus, early diagnosis and treatment are important. Fractures of the superior orbital wall are often accompanied by skull fractures. Most of these patients are unable to perform an early ocular evaluation due to neurosurgery and treatment. These patients are more likely to show tissue adhesion, making it difficult to properly dissect the tissue for wall reconstruction during surgery. CASE PRESENTATION: This report details a case of superior orbital wall reconstruction using superior orbital rim osteotomy in a patient with a superior orbital wall fracture involving severe tissue adhesion. Three months after reconstruction, there were no significant complications. CONCLUSION: In a patient with a superior orbital wall fracture, our procedure is helpful in securing the visual field and in delamination of the surrounding tissue.

A retrospective clinical investigation for the effectiveness of closed reduction on nasal bone fracture / 대한악안면성형재건외과학회지

BACKGROUND@#The nasal bone is the most protruding bony structure of the facial bones. Nasal bone fracture is the most common facial bone fracture. The high rate of incidence of nasal bone fracture emphasizes the need for systematical investigation of epidemiology, surgical techniques, and complications after surgery. The objective of this study is to investigate the current trends in the treatment of nasal bone fractures and the effectiveness of closed reduction depending on the severity of the nasal bone fracture.@*PATIENTS AND METHODS@#A total of 179 patients with a nasal bone fracture from 2009 to 2017 were enrolled. Their clinical examination, patient's records, and radiographic images of nasal bone fractures were evaluated.@*RESULTS@#Patients ranged from children to elderly. There were 156 (87.2%) males and 23 (12.8%) females. Traffic accident (36.9%) was the most common cause of nasal fracture. Orbit fracture (44 patients, 24.6%) was the most common fracture associated with a nasal bone fracture.Complications after surgery included postoperative deformity in 20 (11.2%) patients, nasal obstruction in 11 (6.1%) patients, and olfactory disturbances in 2 (1.1%) patients and patients with more severe nasal bone fractures had higher rates of these complications.@*CONCLUSION@#Closed reduction could be performed successfully within 2 weeks after injury.

Orbicularis oris muscle reconstruction and cheiloplasty with Z-plasty in a patient with a transverse facial cleft / 대한악안면성형재건외과학회지

BACKGROUND@#Transverse facial clefts are Tessier's number 7 facial cleft among numbers 1–15 in Tessier's classification of craniofacial malformations, which varies from a simple widening oral commissure to a complete fissure extending towards the external ear.CASE PRESENTATION: In a patient with a transverse facial cleft, to functionally arrange the orbicularis oris muscle and form the oral commissure naturally, we performed a surgical procedure including orbicularis oris muscle reconstruction and cheiloplasty with Z-plasty.@*CONCLUSION@#We achieved good results functionally and esthetically by orbicularis oris muscle reconstruction and cheiloplasty with Z-plasty. The surgical modality of our anatomical repair and 3 months follow-up results are presented.

Surgical excision of osteochondroma on mandibular condyle via preauricular approach with zygomatic arch osteotomy / 대한악안면성형재건외과학회지

BACKGROUND: Osteochondroma is a benign tumor that tends to develop in mandibular condyle and coronoid process in the craniofacial region. If tumor mass has grown from condyle into the infratemporal space with zygomatic arch obstructing the access, there are risks associated with surgical exposure and local resection of these masses. CASE PRESENTATION: This study reports on a case of osteochondroma on mandibular condylar head where we treated with surgical excision via preauricular approach with 3D analysis. After the local resection, there were no surgical and post-operative complications until 8-month follow-up period. CONCLUSIONS: In local excision of osteochondroma, our method is a minimally invasive method. It is a good example of osteochondroma treatment.

Treatment of dental implant displacement into the maxillary sinus / 대한악안면성형재건외과학회지

BACKGROUND: Displacement of dental implants into the maxillary sinus is rare, but it primarily occurs in patients with severe pneumatization of the maxillary sinus and/or deficiency of the alveolar process. Some complications such as the infection of the paranasal sinuses and formation of the oroantral fistula can be followed by the displacement of a dental implant. Therefore, the displaced implant has to be removed immediately with surgical intervention show and another plan for rehabilitation should be considered. MAIN BODY: The conventional procedure for the removal of a displaced implant from the maxillary sinus involves sinus bone grafting and new implant placement performed in two or more steps with a significant time gap in between. Simplification of these surgical procedures can decrease the treatment duration and patient discomfort. CONCLUSIONS: In this review, we discuss the anatomical characteristics of the maxillary sinus and the complications associated with implant displacement into the sinus.

Evaluation of clinical outcomes of implants placed into the maxillary sinus with a perforated sinus membrane: a retrospective study / 대한악안면성형재건외과학회지

BACKGROUND: The aim of this study was to evaluate the clinical outcomes of implants that were placed within the maxillary sinus that has a perforated sinus membrane by the lateral window approach. METHODS: We examined the medical records of the patients who had implants placed within the maxillary sinus that has a perforated sinus membrane by the lateral approach at the Department of Oral and Maxillofacial Surgery of Chonnam National University Dental Hospital from January 2009 to December 2015. There were 41 patients (male:female = 28:13). The mean age of patients was 57.2 ± 7.2 years at the time of operation (range, 20–76 years). The mean follow-up duration was 2.1 years (range, 0.5–5 years) after implant placement. Regarding the method of sinus elevation, only the lateral approach was included in this study. RESULTS: Ninety-nine implants were placed in 41 patients whose sinus membranes were perforated during lateral approach. The perforated sinus membranes were repaired with a resorbable collagen membrane. Simultaneous implant placements with sinus bone grafting were performed in 37 patients, whereas delayed placements were done in four patients. The average residual bone height was 3.4 ± 2.0 mm in cases of simultaneous implant placement and 0.6 ± 0.9 mm in cases of delayed placement. Maxillary bone graft with implant placement, performed on the patients with a perforated maxillary sinus membrane did not fail, and the cumulative implant survival rate was 100%. CONCLUSIONS: In patients with perforations of the sinus mucosa, sinus elevation and implant placement are possible regardless of the location and size of membrane perforation. Repair using resorbable collagen membrane is a predictable and reliable technique.

Retrospective clinical study of an implant with a sandblasted, large-grit, acid-etched surface and internal connection: analysis of short-term success rate and marginal bone loss / 대한악안면성형재건외과학회지

BACKGROUND: The purpose of this retrospective study was to evaluate the clinical utility of an implant with a sandblasted, large-grit, acid-etched (SLA) surface and internal connection. METHODS: Six patients who received dental implants in the Department of Oral and Maxillofacial Surgery, Chonnam National University Dental Hospital, were analyzed by factors influencing the success rate and marginal bone loss. Factors included patient’s age, sex, implant installation site, whether bone graft was done, type of bone graft materials, approaching method if sinus lift was done, and the size of the fixture. In addition, the marginal bone loss was analyzed by using a radiograph. RESULTS: All implants were successful, and the cumulative survival rate was 100 %. Average marginal bone loss of 6 months after the installation was 0.52 mm and 20 months after the functional loading was 1.06 mm. Total marginal bone resorption was 1.58 mm on average. There was no statistically significant difference in mesial and distal marginal bone loss. CONCLUSIONS: The short-term clinical success rate of the implant with an SLA surface and internal connection was satisfactory. Moreover, the marginal bone loss was also consistent with the implant success criteria.

Retrospective study on factors affecting the prognosis in oral cancer patients who underwent surgical treatment only / 대한악안면성형재건외과학회지

BACKGROUND: This study was performed to evaluate their 5-year survival rates and identify the factors affecting the prognosis of oral cancer patients who had undergone surgical treatment only. METHODS: Among 130 patients who were diagnosed with malignant tumor of oral, maxillofacial, and surgical treated in the Department of Oral and Maxillofacial Surgery at Chonnam National University Hospital within a period from January 2000 to December 2010, for 11 years, 84 patients were investigated who were followed up for more than 5 years after radical surgery; oral cancer is primary and received only surgical treatment. The survival rate according to gender, age, type and site of cancer, TNM stage, cervical lymph node metastasis and its stage, recurrence or metastasis, time of recurrence and metastasis, and differentiation were investigated and analyzed. RESULTS: Overall, 5-year survival rate in patients who received only surgical treatment was 81.2 %, and disease-specific 5-year survival rate was 83.1 %. The disease-specific 5-year survival rate based on TNM stage, metastasis of cervical lymph node, N stage, and presence of recurrence/metastasis was a significant difference (p 0.05). CONCLUSIONS: These results suggest that good survival rate can be obtained with surgical treatment only, and stage of oral cancer, cervical lymph node metastasis and stage, recurrence or metastasis, time of recurrence, and metastasis have a significant effect on survival rate in oral cancer patients.

Condylar positioning changes following unilateral sagittal split ramus osteotomy in patients with mandibular prognathism / 대한악안면성형재건외과학회지

BACKGROUND: This study was performed to evaluate three-dimensional positional change of the condyle using three-dimensional computed tomography (3D-CT) following unilateral sagittal split ramus osteotomy (USSRO) in patients with mandibular prognathism. METHODS: This study examined two patients exhibiting skeletal class III malocclusion with facial asymmetry who underwent USSRO for a mandibular setback. 3D-CT was performed before surgery, immediately after surgery, and 6 months postoperatively. After creating 3D-CT images by using the In-vivo 5(TM) program, the axial plane, coronal plane, and sagittal plane were configured. Three-dimensional positional changes from each plane to the condyle, axial condylar head axis angle (AHA), axial condylar head position (AHP), frontal condylar head axis angle (FHA), frontal condylar head position (FHP), sagittal condylar head axis angle (SHA), and sagittal condylar head position (SHP) of the two patients were measured before surgery, immediately after surgery, and 6 months postoperatively. RESULTS: In the first patient, medial rotation of the operated condyle in AHA and anterior rotation in SHA were observed. There were no significant changes after surgery in AHP, FHP, and SHP after surgery. In the second patient, medial rotation of the operated condyle in AHA and lateral rotation of the operated condyle in FHA were observed. There were no significant changes in AHP, FHP, and SHP postoperatively. This indicates that in USSRO, postoperative movement of the condylar head is insignificant; however, medial rotation of the condylar head is possible. Although three-dimensional changes were observed, these were not clinically significant. CONCLUSIONS: The results of this study suggest that although three-dimensional changes in condylar head position are observed in patients post SSRO, there are no significant changes that would clinically affect the patient.

Aplastic anemia and dental implant rehabilitation: a clinical trial

The purpose of this study was to investigate implant-supported restoration as a technique for restoring missing teeth in patients with aplastic anemia. Recurrent bleeding from wound sites leads to persistent release of iron in the tissue. Excessive iron in tissue is related to clinical findings, including fibrosis, poor wound healing, and high level of angiogenesis, which are possible etiological factors of reduced osseointegration. A 44-year-old female patient with aplastic anemia was treated with multiple endosseous implants throughout the mandible and in the posterior region of the maxilla. After 14 implants were placed, radiological and clinical parameters were assessed during the follow-up period. Marginal bone did not change significantly during the follow-up period. The fine trabecular bone in intimate contact and enclosing the implant fixture was sufficient for successful osseointegration. None of the 14 implants were associated with compilations during the seven-year experimental period. This study suggests that dental implant procedures are a safe and reliable treatment option for restoration of missing dentition in patients with aplastic anemia.

Odontogenic infection involving the secondary fascial space in diabetic and non-diabetic patients: a clinical comparative study

OBJECTIVES: This retrospective study was performed to evaluate the clinical impact of diabetes mellitus on the prognosis in secondary space infection. MATERIALS AND METHODS: Medical records, radiographic images, computed tomography, and microbial studies of 51 patients (25 diabetic patients and 26 non-diabetic patients) were reviewed. Patients were diagnosed as secondary fascial space infections with odontogenic origin and underwent treatment at Chonnam National University Hospital, in Department of Oral and Maxillofacial Surgery, from January 2007 to February 2009. RESULTS: Compared to patients without diabetes, patients with diabetes were presented with the following characteristics: older age (diabetic patients: 62.9 years, non-diabetic patients, 47.8 years), more spaces involved (diabetic patients, 60%; non-diabetic patients, 27.3%), more intense treatment, longer hospitalization (diabetic patients, 28.9 days; non-diabetic patients, 15.4 days), higher white blood cell and C-reactive protein values, higher incidence of complication (diabetic patients, 40%; non-diabetic patients, 7.7%), and distinctive main causative microorganisms. CONCLUSION: These results suggest that the prognosis of diabetic patients is poorer than that of non-diabetic patients in secondary space infections since they had greater incidence rates of involved spaces, abnormal hematologic findings, more complications, and additional procedures, such as tracheostomy.

Three Dimensional Study on the Postoperative Stability after Advancement of Maxilla Using Le Fort I Osteotomy

0.05). In transverse plane, the distance between S1-S0 of PNS was -3.87+/-2.37 mm, S2-S0 of PNS was -3.79+/-2.39 mm, and S1-S2 of PNS was -0.08+/-0.18 mm. There were significant differences between these data (P<0.05). In coronal plane, the distance between S1-S0 of A-point was 3.99+/-0.86 mm, S2-S0 was 3.57+/-1.09 mm, and S1-S2 was 0.42+/-0.42 mm. There were significant differences between these data (P<0.05). In coronal plane, the distance between S1-S0 of PNS was 3.82+/-0.96 mm, S2-S0 was 3.43+/-0.91 mm, and S1-S2 was 0.39+/-0.49 mm. There were significant differences between these data (P<0.05). In transverse plane, it was estimated that PNS has no statistical postoperative stability in the same direction. In coronal plane, it was estimated that both A-point and PNS had no statistical postoperative stability (P<0.05).CONCLUSION: Clinically, the operation plan needs to take into account of the maxillary relapse.

The Bone Formation Potency on the Titanium Cap According to the Pore on the Rabbit Calvarium

Evaluation of augmented alveolar bone with vertical alveolar distraction osteogenesis and implant installation

INTRODUCTION: The purpose of this study was to evaluate the clinical result of vertical alveolar distraction, especially the distracted alveolar bone and installed implants. MATERIALS AND METHODS: Twenty-one patients who have been received the vertical alveolar distraction and implant installation on 22 areas (3 maxilla and 19 mandible) using intraoral alveolar distraction device were examined. After consolidation period of 3-4 months, distraction devices were removed and 91 implants were installed in the distracted alveolar bone. The distracted bone and implants were evaluated clinically and radiographically. RESULTS: Mean height of distracted alveolar bone was 7.5+/-3.2 mm (range: 2.5-15.0 mm). Mean follow-up period after completion of the distraction was 3.1 years (range: 1.4-11.5 years). Mean resorption of distracted alveolar bone was 1.6+/-1.8 mm. The success and survival rates of implants was 95.3% and 100%, respectively. CONCLUSION: Results of this study indicate that vertical alveolar distraction procedure is a useful and stable method for alveolar ridge augmentation and implantation.

Changes of Pharyngeal Airway Space after Mandibular Setback Surgery in Computed Tomography Images

The effect of platelet rich plasma in bone formation on implant installation in the tibia of beagle dogs

INTRODUCTION: The purpose of this study is to evaluate the effect of platelet rich plasma in bone formation and osseointegration of implant installed in the bone marrow space. MATERIALS AND METHODS: Five beagle dogs were used as experimental animals. Two implants were installed on each tibia in the dogs. Implants of the control group were installed with no additional graft. Those of the experimental group 1 were installed with autogenous bone graft from the ilium autogenous bone. Platelet rich plasma (PRP) alone was used in experimental group 2 and the mixture of PRP and autogenous bone was used in experimental group 3. The animals were sacrificed at 8 weeks after implantation. The parts of tibia containing implant were harvested and radiographs were taken for radiographic examination. The specimens were prepared for histological examination and histomorphometric analysis of implant-bone contact ratios. RESULTS: 1. All implants showed sufficient osseointegration in the cortical bone radiographically and histologically, but osseointergration in the marrow space was not satisfactory. 2. Histomorphometrically, the implant-bone contact ratios in the bone marrow was sequentially high in the experimental group 3 (autogenous bone + PRP group), group 1 (autogenous bone group), group 2 (PRP group), and control group (non-additive). 3. It was verified that there was statistical significance between two experimental groups (group 1 and 3) and the other groups (group 2 and control group). (P<0.005) 4. However, there was no statistical significance between group 3 and group 1, also group 2 and control group respectively. CONCLUSION: These results suggest that platelet rich plasma is effective to osseointegration in the implant installation but there is no statistical significance.

Expression of osteoclastogenesis related factors in dental implant patients

INTRODUCTION: Bone resorption is a unique function of osteoclasts. Osteoclasts are a specialized macrophage polykaryon whose differentiation is regulated principally by macrophage colony-stimulating factors, receptor activator of nuclear factor kappaB ligand (RANK) ligand, osteoprotegerin (OPG), and interleukins (IL). Reflecting the integrin-mediated signals, osteoclasts develop a specialized cytoskeleton that allows it to establish an isolated micro-environment between itself and the bone, wherein matrix degradation occurs by a process involving proton transport. The levels of IL-1, IL-6, OPG, and prostaglandin E2 (PGE2) expression were evaluated to study the correlations between dental implant teeth and the adjacent teeth. MATERIALS AND METHODS: The exudate of the gingival crevice acquired from dental implants, adjacent teeth, opposite teeth and contralateral teeth of 24 patients. RESULTS: 1. The levels of IL-1, IL-6, OPG and PGE2 expression in dental implant teeth were higher than those of the contralateral teeth. 2. IL-1 revealed a higher expression level in the adjacent teeth than in dental implant teeth. 3. The dental implant teeth and adjacent teeth did not show a remarkable difference in the level of IL-1 expression. 4. All the other cytokines were strongly expressed in the dental implant compared to the adjacent teeth. CONCLUSION: These results suggest that there might be close correlation between dental implant teeth and adjacent teeth in terms of the expressions of cytokines that affect the development and regulation of osteoclasts.

Evaluation of bone formation by recombinant human BMP-2 and rapid prototype titanium cap in rabbit calvaria using micro computed tomography

INTRODUCTION: This study examined the effect of recombinant human bone morphogenetic protein (rhBMP)-2 and beta-tricalcium phosphate (beta-TCP) on new bone formation in a rabbit calvarium using a rapid prototype titanium cap (RP Ti cap). MATERIALS AND METHODS: Eight New Zealand white rabbits were used in this study. Hemispherical RP Ti caps (10 mm in diameter) were implanted subperiosteally on the rabbit calvaria. beta-TCP was filled in the RP Ti cap in the control group, and rhBMP-2 soaked beta-TCP was used in experimental group. The rabbits were sacrificed 2 and 4 weeks after the operation. The volume and pattern of newly formed bone was analyzed by micro computed tomography (CT). RESULTS: Macroscopically, there were no abnormal findings in any of the animals. The micro CT images revealed new bone from the calvaria that expanded gradually toward the top of the titanium cap, particularly along the inner surface of the titanium cap in the experimental group at 4 weeks after grafting. There was no significant difference in new bone volume ratio between the control and experimental groups at 2 weeks after grafting. There was a statistically significant difference in the new bone volume ratio between the experimental (14.1+/-1.8 %) and control (7.2+/-1.5 %) groups at 4 weeks after grafting (P<0.01). CONCLUSION: The RP Ti cap can effectively guide new bone formation and rhBMP-2 can induce the new bone formation.