A new guide for enhancing dental implant placement: an in vitro assessment of accuracy.

This study aimed to design a new surgical guide for controlling the mesiodistal distance between implant osteotomies and adjacent teeth as well as the osteotomy depth in partially edentulous patients. The guide kit was designed with design software and milled with a CNC (computer numerical control) router. The guide consisted of 2 components-stoppers and crown guides-for determining the drilling depth and mesiodistal position, respectively. The stoppers were designed in 7.5-, 9.5-, and 11.5-mm lengths, and the crown guides were fabricated with outer diameters of 5.0, 6.0, 7.0, and 8.0 mm. The accuracy of the guide was assessed by preparing a total of 20 implant osteotomies in 4 partially edentulous models and comparing the dimensions of the actual osteotomies to the values that were predicted to occur with the use of the surgical guides. Osteotomies were prepared using the 7.5-mm stopper with either the 7.0- or 8.0-mm crown guide. Cone beam computed tomography (CBCT) was used to obtain images for analysis of osteotomy-tooth mesiodistal distances, which were predicted to be 3.0 or 5.5 mm, depending on position; interosteotomy mesiodistal distances, which were predicted to be 3.0 mm; and osteotomy depth, which was predicted to be 11.5 mm. A 1-sample t test was used to determine if there were significant differences between the predicted values and the measurements of the guided osteotomies on the CBCT images of the mandibular models, and an independent t test was conducted to compare the results of 3.0- and 5.5-mm osteotomy-tooth distances (α = 0.05). Differences between the predicted and actual values of the interosteotomy mesiodistal distance (P = 0.516) and osteotomy depth (P = 0.847) were not statistically significant. The actual osteotomy-tooth mesiodistal distances were significantly different from the predicted values of 3.0 (P = 0.000) and 5.5 mm (P = 0.001), with higher mean differences of 0.46 and 0.60 mm, respectively. The designed guide had a high accuracy in achieving optimal linear interosteotomy mesiodistal distances and osteotomy depths, and the obtained mean values were clinically acceptable.

Accuracy of computer-guided implant surgery in partially edentulous patients: a prospective observational study.

PURPOSE: This study aims to evaluate the amount of distortion using computer-guided implant surgery with 3D printed surgical guides in limited edentulous spaces. MATERIALS AND METHODS: 25 bone level self-tapping implants (Straumann® BL and BLT) were randomly inserted in either distal or intercalary posterior mandibular edentulism using a fully digital protocol and 3D printed surgical guides. Amount of inaccuracy was evaluated after superimposing the 3 coordinates of virtually planned and final implant images, which were obtained using intra-oral scans and scan bodies. Four evaluation parameters were considered: origo-displacement, error depth, apical displacement and angle between the planned and the placed implant. RESULTS: The average of distortion was 0.71 mm for the origo-displacement, 0.36 mm for the error depth, 0.52 mm for the horizontal displacement and 3.34º for the error angle. CONCLUSION: The major reason of exclusion was CBCT artifacts. Results of this study were aligned with the results of previous studies concerning partially edentulous spaces. CAD/CAM manufacturing process did not result in significant distortion whilst the biggest part of distortions originated from the surgical process. The learning curve in computer-guided implant surgery presented an important source of inaccuracy.

Undesirable course of an oral implant rehabilitation in a patient with a long history of bulimia nervosa: case report and review of the literature.

BACKGROUND: Bulimia nervosa is an eating disorder resulting in an intended weight loss due to decreased food intake, induced vomiting, or hyperactivity, and is observed frequently between 12 and 25 years of age. One of the complications is early tooth loss. Moreover, since bulimia nervosa patients suffer from increased atrophy of the alveolar processes, oral rehabilitation even with short dental implants may be impossible. In these cases, lateralization or transposition of the inferior alveolar nerve (IAN) followed by implant placement can be useful. CASE PRESENTATION: A 40-year-old woman with a long-lasting history of bulimia nervosa requested a fixed rehabilitation of her partially edentulous mandible. In 2012, a bilateral IAN transposition approach was performed using piezosurgery, and without any postoperative neurosensory alterations. Two years later, bilateral insertion of each two implants was followed by an inflammatory destabilization of the lower left mandible; subsequent to the implant removal, a fracture occurred, and the latter was stabilized by osteosynthesis plates. In 2017, three additional implants were placed, finally providing the patient with a fixed restoration on five implants. CONCLUSION: Eating disorders may have a tremendous impact on both physical condition and oral health, resulting in early tooth loss and severe bone atrophy. IAN transposition is a viable treatment option to enable installing fixed prostheses via dental implants, but the latter will clearly increase the risk of inflammation and interruption of mandibular continuity. Close clinical and radiologic monitoring is mandatory to adequately respond to complications such as peri-implant mucositis, peri-implantitis, osteomyelitis, or concomitant fractures.

Influence of the abutment height and connection timing in early peri-implant marginal bone changes: A prospective randomized clinical trial.

AIM: The aim of this study was to compare the influence of the abutment height and insertion timing on early marginal bone loss (MBL) in posterior mandibular partial implant-supported restorations. MATERIAL AND METHODS: The study was planned as a prospective, randomized, controlled parallel group including subjects in need of at least two implants for the restoration of an edentulous posterior mandibular area. The patients were allocated into Groups A (implants immediately connected to 2-mm height abutments), B (immediately connected 1-mm height abutments), and C (2-mm abutments were inserted in a second-stage surgery). Each subject was placed in a 1-year follow-up program, including examination assessment of various soft tissue and bone-level parameters. RESULTS: A total of thirty-three patients, including sixty-eight implants, were enrolled in this study. One implant was lost on group C after the first month of healing. A mean MBL change of 0.719 ± 0.361, 0.651 ± 0.379, and 0.754 ± 0.672 mm was computed for groups A, B, and C, respectively, with no significant differences found. The early MBL at T1 was an independent predictor variable for the marginal bone alterations that were assessed at T3 (p < 0.001). CONCLUSION: The first-month MBL variation is a predictor factor of the bone alterations that might occur after 1 year of treatment. The early connection of final prosthetic abutments with distinct heights does not seem to reduce the 1-year MBL rate when compared with traditional treatment protocols.

New classification of maxillary sinus contours and its relation to sinus floor elevation surgery.

BACKGROUND: It is complicated to select an appropriate sinus floor elevation and the procedure for sinus floor elevation lacks of consensus. Sinus contour plays an important role in choosing a surgery approach. But there are still no published articles revealing the influence of sinus contours to sinus floor elevation surgery. PURPOSE: We propose a new classification depending on sinus contours from cone-beam computed tomography (CBCT), analyze clinical characters of different types, and investigate the relationship between sinus contours and sinus floor elevation. MATERIALS AND METHODS: We divide sinus into five categories: narrow tapered, tapering, ovoid, square, and irregular. For the first four types, subtypes are classified into three categories: without recess, with buccal-sinus-recess (BSR), and with palate-nasal-recess (PNR). For irregular type, subtypes are classified into three categories: tooth protruding into sinus floor, irregular floor, and septa/exostosis on sinus floor. Then the distribution features of sinuses of 698 patients are described. Sinus widths are measured at second premolar, first and second molar on both sides, and are compared among different types and subtypes. RESULTS: Narrow tapered sinus occupies 88% at second premolar sites, while tapered sinus occupies almost 50% at first and second molar sites. At second premolar and first molar sites, 62% are without recess types. While 92% are without recess types at second molar. Sinuses with BSR present in only three of 3765 sites. There is an increasing trend of sinus width from narrow tapered to irregular type. Sinus width of the group with recesses is significantly higher than the one without recess. At the end, we provide corresponding treatment recommendations for each sinus types and subtypes. CONCLUSION: This is the first classification system that gives treatment recommendations for sinus floor elevation surgery based on sinus contours. The classification system is consistent, easy to visualize, and practicable.

Clinical factors in prosthodontic treatment of children with genetic defects.

BACKGROUND: Prosthodontic treatment of children with genetic disorders is an area that is rarely examined in the current specialist literature. Few prosthodontists will undertake treatment of such patients, who will more often be referred to an orthodontic specialist. After examining the 4 cases of children with genetic disorders described in this paper, it can be concluded that when a prosthodontist includes a few additional procedures in the treatment process, he or she can successfully help such patients. OBJECTIVES: The aim of this paper is to indicate the clinical difficulties faced by prosthodontists who undertake prosthodontic rehabilitation of children with genetic disorders. MATERIAL AND METHODS: The paper is based on data collected during the prosthodontic treatment of 4 children, aged 5-12 years with genetic defects, and analysis of the body of work concerning these defects and their treatment. RESULTS: Presentation of guidelines for the prosthodontic treatment process and creation of dentures for treated children based on extended procedures. CONCLUSIONS: A prosthodontist is a crucial person in a team of specialists treating disorders within the face among children with a genetic predisposition. A basic knowledge of orthodontics and psychology facilitates the treatment. Prosthetic restoration in the treatment group does not always require complicated operations. Individualization of the tools for downloading orthodontic impressions, designing denture elements and an increased number of checkups are the additional procedures. For the clinician, the emotional aspect of the treatment is the main impediment. Maintaining a good relationship with a patient and his or her caregivers requires interpersonal skills.

Immediate loading of subcrestally placed dental implants in anterior and premolar sites.

PURPOSE: Immediate loading of dental implants has been evolving into an appropriate procedure for the treatment of partially edentulous jaws. The purpose of this study was to evaluate the clinical success and radiological outcome of immediately and delayed loaded dental implants in anterior and premolar sites. MATERIALS AND METHODS: In this retrospective study, data of 163 individuals requiring tooth removal with subsequent implant placement in anterior and premolar sites were analyzed. Implants were immediately loaded by provisional acrylic resin bridges or loaded with delay. Implants were followed up annually for up to 9 years including intraoral radiographs. RESULTS: A total of 285 implants in 163 patients were placed. 218 implants were immediately loaded and 67 implants with delay. Fifteen implants failed during the follow-up period resulting in survival rates of 94.5% for immediate loading and 95.5% for delayed loading. After an initial decrease of 0.3 mm in the first 12 months the marginal bone level remained stable. No statistically significant differences were found in marginal bone loss between immediately and delayed loaded implants (P = 0.518, 95% CI). CONCLUSION: Within the limits of this study, immediate loading of immediately subcrestally placed dental implants in anterior and premolar sites is a reliable treatment option for dental rehabilitation.

Radiographic Screening of Patients in a Dental School using the Prosthodontic Diagnostic Index.

INTRODUCTION: Organization of the findings associated with various diagnostic aids plays a key role in formulating the treatment plan of the patients undergoing dental and medical treatment. Enhanced consistency in diagnosing and classifying prosthodontic patients is the basic purpose of various classification systems. Hence, we planned this study to classify partially edentulous patients and completely dentate patients at the undergraduate clinics using the prosthodontic diagnostic index (PDI). MATERIALS AND METHODS: This study included classification of 13,599 edentulous patients who attended the clinics of undergraduate students of all the levels. Screening of all the patients was done radiographically with a digital orthopantomograph (OPG), and the data were saved in the computer system. The intraoral periapical radiographs (IOPA) taken for all the affected areas were also saved in the system. Based on the OPG and IOPA, the patients were classified into various classes. All the data of the patients were recorded and analyzed. RESULTS: Total number of patients screened was 17,220, out of which 3,621 were under 18 years of age and were excluded from the study. Most of the patients belonged to the age group of 31 to 45 years: 5,360 (39.4%) patients (3,817 [43.0%] males and 1,543 [32.5%] females) were class I; 2,730 (20.0%) patients (1,729 [19.5%] males and 1,001 [21.1%] females) were class II; 4,576 (33.7%) patients (2,835 [32.0%] males and 1,741 [36.8%] females) were class III; and 933 (6.9%) patients (483 [5.5%] males and 450 [9.5%] females) were class IV. CONCLUSION: There is a need to introduce PDI as a screening tool during the initial examination of the patient and to achieve a proper distribution of the patients among various levels of students, interns, and postgraduates. CLINICAL SIGNIFICANCE: Introduction of PDI will improve the treatment planning and prognosis of edentulous patients.

Analyzing Dental Implant Sites From Cone Beam Computed Tomography Scans on a Tablet Computer: A Comparative Study Between iPad and 3 Display Systems.

PURPOSE: The aim of this study was to compare a medical-grade PACS (picture archiving and communication system) monitor, a consumer-grade monitor, a laptop computer, and a tablet computer for linear measurements of height and width for specific implant sites in the posterior maxilla and mandible, along with visualization of the associated anatomical structures. MATERIAL AND METHODS: Cone beam computed tomography (CBCT) scans were evaluated. The images were reviewed using PACS-LCD monitor, consumer-grade LCD monitor using CB-Works software, a 13″ MacBook Pro, and an iPad 4 using OsiriX DICOM reader software. The operators had to identify anatomical structures in each display using a 2-point scale. User experience between PACS and iPad was also evaluated by means of a questionnaire. RESULTS: The measurements were very similar for each device. P-values were all greater than 0.05, indicating no significant difference between the monitors for each measurement. The intraoperator reliability was very high. The user experience was similar in each category with the most significant difference regarding the portability where the PACS display received the lowest score and the iPad received the highest score. CONCLUSIONS: The iPad with retina display was comparable with the medical-grade monitor, producing similar measurements and image visualization, and thus providing an inexpensive, portable, and reliable screen to analyze CBCT images in the operating room during the implant surgery.

Reconstruction-Based Digital Dental Occlusion of the Partially Edentulous Dentition.

Partially edentulous dentition presents a challenging problem for the surgical planning of digital dental occlusion in the field of craniomaxillofacial surgery because of the incorrect maxillomandibular distance caused by missing teeth. We propose an innovative approach called Dental Reconstruction with Symmetrical Teeth (DRST) to achieve accurate dental occlusion for the partially edentulous cases. In this DRST approach, the rigid transformation between two symmetrical teeth existing on the left and right dental model is estimated through probabilistic point registration by matching the two shapes. With the estimated transformation, the partially edentulous space can be virtually filled with the teeth in its symmetrical position. Dental alignment is performed by digital dental occlusion reestablishment algorithm with the reconstructed complete dental model. Satisfactory reconstruction and occlusion results are demonstrated with the synthetic and real partially edentulous models.

Influence of Healing Period Upon Bone Turn Over on Maxillary Sinus Floor Augmentation Grafted Solely with Deproteinized Bovine Bone Mineral: A Prospective Human Histological and Clinical Trial.

PURPOSE: To investigate the influence of maturation timing upon histological, histomorphometric and clinical outcomes when deproteinized bovine bone mineral (DBBM) was used as a sole biomaterial for staged maxillary sinus floor augmentation (MSFA). MATERIALS AND METHODS: Patients with a posterior edentulous maxillary situation and a vertical bone height ≤ 4 mm were included in this study. A staged MSFA was carried out. After MSFA with DBBM as a sole grafting material, biopsy cores were harvested with simultaneous implant placement followed by a healing period of 5, 8, and 11 months, respectively. Micro-CT, histologic and histomorphometric analyses were performed. RESULTS: Forty-one patients were enrolled and 38 bone core biopsies were harvested. Significantly greater BV/TV was observed between 5- and 8-month healing from micro-CT analysis. Histomorphometric analyses showed the ratio of mineralized newly formed bone increased slightly from 5 to 11 months; however, no statistically significant difference was reached (p = .409). Residual bone substitute decreased from 37.3 ± 5.04% to 20.6 ± 7.45%, achieving a statistical significant difference from of 5 up to 11 months (p < .01). Moreover, no implant failure, biological or technical complication occurred after 12-month follow-up of functional loading. CONCLUSION: DBBM utilized as sole grafting material in staged MSFA demonstrated to be clinically effective regardless of the healing period. Histomorphometrical and micro-CT assessments revealed that at later stages of healing (8 and 11 months) there is a higher proportion of newly-bone formation compared to earlier stages (5 months). Moreover, the longer the maturation period, the substantially lesser remaining biomaterial could be expected. Even though, these facts did not seem to negatively impact on the implant prognosis 1-year after loading.

Clinical study on mandibular fracture after marginal resection of the mandible.

OBJECTIVES: Postoperative mandibular fracture (PMF) after marginal resection (MR) of the mandible remains an unresolved issue, and it has been reported that at least 10 mm of postoperative mandibular body height (PMBH) is required to prevent PMF. This study evaluated the clinical, physical, and structural risk factors for PMF in MR patients and determined appropriate preventive measures for PMF. STUDY DESIGN: This retrospective study included 44 patients with lower gingival carcinoma who underwent MR. PMF occurred in four of these patients. Thirteen associated factors identified from medical records and radiographs were statistically analyzed. RESULTS: Mandibular body height (MBH) preservation ratio originally evaluated as less than 0.3, more than 20 remaining teeth after surgery, and inferior alveolar canal (IAC) exposure were significant risk factors for PMF. Prostheses and number of remaining teeth were also correlated with PMF. CONCLUSIONS: The preserved mandibular bone should be reinforced in patients with an MBH preservation ratio of less than 0.3, more than 20 remaining teeth after surgery, and intraoperative IAC exposure. Patients with prostheses are at an increased risk of PMF compared with those without because of stable occlusion and a strong occlusal force. Our novel findings provide useful reference standards for PMF prevention in MR patients.

Assessment of mandibular posterior regional landmarks using cone-beam computed tomography in dental implant surgery.

The aim of this study has been to evaluate and correlate the anatomical features of the posterior mandibular region (submandibular fossa depth, bone height and thickness, and mandibular canal corticalization) to improve accident prevention and allow safe planning in implantology. Four parasagittal sections of cone-beam computed tomography (CBCT) from 100 patients were bilaterally analyzed. Linear measurements of the submandibular fossa depth, bone height and thickness were performed. The submandibular fossa was also classified into non-influential undercuts and influential undercuts for implant placement. Mandibular canal corticalization was also evaluated and classified according to the visualization. Data on patient age and gender were also collected. Forty-one scans (41%) were from male patients, and 59 (59%) were from female patients. Patient age ranged between 18 and 84 years, with an average age of 51.37 years. The submandibular fossa depth and implant bone thickness had a significant effect on the variability of the sample (46.1% and 22.3%, respectively). The submandibular fossa depth was quite variable, and the highest values were observed in the posterior regions. In 18.27% of the cases, the presence of the fossa directly influenced implant placement, considering a bone height of 10mm (standard implant). A significant correlation was observed between fossa depth and bone thickness. Thus, greater attention should be paid to thick ridges; although thick ridges are favorable, they may be associated with deeper submandibular fossae. The mandibular canal was the most influential anatomical structure in the premolar region due to the reduced bone height in this region and the greater difficulty in viewing the canal, and the submandibular fossa was the most influential structure in the molar region due to lower bone height leading up to the fossa and the greater fossa depth in this region. Therefore, CBCT is an important tool for assessing the mandibular region and planning for safe implant installation in the posterior mandible. Furthermore, comprehensive evaluation of the characteristics of this region is necessary, as the variables - submandibular fossa depth, bone height and thickness, and mandibular canal corticalization - are related and must be considered together when planning.

Combining guided alveolar ridge reduction and guided implant placement for all-on-4 surgery: A clinical report.

Immediate restoration with the all-on-4 concept has become an established treatment option. The technique involves alveoloplasty before implant placement to provide space for the prosthetic components and to provide a platform on which dental implants can be placed in clinical situations where a knife-edge alveolar ridge is present. Guided implant surgery involves the fabrication of a guide by using data from cone-beam computed tomography (CBCT) and implant surgery performed without flap reflection. In the presented technique, a printed cast based on a CBCT is used to fabricate a guide for both alveolar ridge reduction and guided implant surgery. The alveolar ridge reduction and implant surgery are virtually simulated in the laboratory to provide space for the restorative components and to avoid critical anatomic landmarks (mental nerve or perforation of the lingual mandibular plate). The described surgical guide enables guided alveolar ridge reduction and guided implant placement where the implant placement performed in the laboratory can be duplicated clinically during implant surgery.

An Analysis of Frequency, Morphology, and Locations of Maxillary Sinus Septa Using Cone Beam Computed Tomography.

PURPOSE: To evaluate the frequency, morphology, and locations of maxillary sinus septa using cone beam computed tomographic (CBCT) imaging of the entire maxillary sinus and to analyze factors influencing the presence or absence of septa. MATERIALS AND METHODS: CBCT images of the maxilla taken during a 1-year study period (October 1, 2012, to September 30, 2013) were evaluated for the presence and type of septa as well as the health or pathology of the maxillary sinus. Differences in age, gender, type of dentition, septa location, and sinus pathology with regard to the incidence of sinus septa were analyzed statistically. RESULTS: The study included 294 maxillary sinuses in 212 patients (126 women and 86 men) with a mean age of 53.8 years. Sinus septa were present in 141 patients (66.5%) and in 166 of 294 sinuses (56.5%). The most common orientation of the septa was coronal (61.8%), 7.6% were oriented axially, and 3.6% were aligned sagittally. Most septa were located on the floor of the maxillary sinus (58.6%), commonly (60.7%) in the region of the first and second molars. The maxillary sinuses were diagnosed in 36.4% of cases as healthy and without thickening of the sinus membrane. Sex was a significant variable in the health of the maxillary sinus; 57.7% of the sinuses in women and 72.3% in men were diagnosed as pathologic. CONCLUSION: Septa are common anatomical structures and are most often found in the first or second molar region on the floor of the maxillary sinus. To prevent possible complications during sinus floor elevation procedures, a thorough three-dimensional radiographic examination of the sinus prior to surgery is recommended.

Vertical Bone Augmentation with an Autogenous Block or Particles in Combination with Guided Bone Regeneration: A Clinical and Histological Preliminary Study in Humans.

BACKGROUND: Vertical ridge augmentation with the use of solid bone blocks or particulate bone autograft, exposed or covered by a nonresorbable expanded polytetrafluoroethylene (ePTFE) membrane, are well known in the literature and have been shown to be effective in treating bone atrophy. PURPOSE: The aim of our study was to assess the two techniques in respect to biological properties of transplanted bone in graft revascularization and bone remodeling in conjunction with dental implants. MATERIALS AND METHODS: Ten patients were treated within the study, with a total of 12 sites with posterior mandibular edentulous ridges with insufficient bone to allow implant placement. Bone regeneration was performed using autogenous intraoral block graft or autogenous particulate graft with an ePTFE barrier membrane. At 6-10 months, reentry surgery was performed; bone biopsies, including microscrews, were harvested; and implants were placed. RESULTS: Eleven sites out of 12 healed uneventfully. A mean height gain of 5.03 mm was achieved. Mean bone-to-implant contact and bone fill were assessed by means of histomorphometric analysis. The block specimens revealed a bone-to-implant contact of 42.34%, and the particulate grafts had a bone-to-implant contact of 26.62% (p < .012). Bone fill values reported were 68.32% and 48.28% (p < .019) for block specimens versus particulate grafts. CONCLUSIONS: The results clearly showed that both techniques were clinically successful for subsequent implant placement and prosthetic rehabilitation. The histological outcomes, including revascularization and bone remodeling, of the two techniques differed significantly. The block grafts outperformed the particulate grafts in terms of bone-to-implant contact and bone fill values; however, the morbidity associated with the donor site of the block must be considered.

Is the Maxillary Sinus Really Suitable in Sex Determination? A Three-Dimensional Analysis of Maxillary Sinus Volume and Surface Depending on Sex and Dentition.

The morphometric analysis of maxillary sinus was recently presented as a helpful instrument for sex determination. The aim of the present study was to examine the volume and surface of the fully dentate, partial, and complete edentulous maxillary sinus depending on the sex. Computed tomography data from 276 patients were imported in DICOM format via special virtual planning software, and surfaces (mm) and volumes (mm) of maxillary sinuses were measured. In sex-specific comparisons (women vs men), statistically significant differences for the mean maxillary sinus volume and surface were found between fully dentate (volume, 13,267.77 mm vs 16,623.17 mm, P < 0.0001; surface, 3480.05 mm vs 4100.83 mm, P < 0.0001) and partially edentulous (volume, 10,577.35 mm vs 14,608.10 mm, P = 0.0002; surface, 2980.11 mm vs 3797.42 mm, P < 0.0001) or complete edentulous sinuses (volume, 11,200.99 mm vs 15,382.29 mm, P < 0.0001; surface, 3118.32 mm vs 3877.25 mm, P < 0.0001). For males, the statistically different mean values were calculated between fully dentate and partially edentulous (volume, P = 0.0022; surface, P = 0.0048) maxillary sinuses. Between the sexes, no differences were only measured for female and male partially dentate fully edentulous sinuses (2 teeth missing) and between partially edentulous sinuses in women and men (1 teeth vs 2 teeth missing). With a corresponding software program, it is possible to analyze the maxillary sinus precisely. The dentition influences the volume and surface of the pneumatic maxillary sinus. Therefore, sex determination is possible by analysis of the maxillary sinus event through the increase in pneumatization.

Bone augmentation of the atrophic anterior maxilla for dental implants using rhBMP-2 and titanium mesh: histological and tomographic analysis.

The loss of multiple teeth or trauma to the anterior maxilla often results in a deficient ridge width for prosthetic tooth rehabilitation. This study evaluated the use of titanium mesh and recombinant human bone morphogenetic protein 2 (rhBMP-2) for the repair of major bone defects in the alveolar bone. Five patients were enrolled in the study; these patients required implant replacements for two contiguous missing teeth in the anterior maxilla, which lacked sufficient bone. Residual ridges were augmented with rhBMP-2 and titanium mesh to direct the geometry of the newly formed bone. Seven months later, a bone biopsy specimen was removed from the implantation site before osteotomy and insertion of dental implants. Cone beam computed tomography (CBCT) scans were obtained preoperatively, postoperatively (baseline), and 48 months after implantation to evaluate implant healing. All dental implants were placed in the grafted sites without the need for further bone augmentation. The most frequent adverse effects were facial oedema and oral erythema. Biopsy specimens were used to evaluate bone quality. CBCT scans provided a prediction of alveolar restoration and long-term success. The combination of rhBMP-2 and titanium mesh provided effective augmentation of the atrophic anterior maxilla prior to implant placement.

Sinus grafting and simultaneous removal of large antral pseudocysts of the maxillary sinus with a micro-invasive intraoral access.

Large antral pseudocysts of the maxillary sinus (APCs) may hamper the elevation of the Schneiderian membrane during sinus grafting and may impair osteo-meatal complex patency after sinus augmentation. Therefore, these should be removed prior to or at the time of sinus grafting. This study presents a new technique that combines enucleation of large APCs during sinus grafting via a lateral approach with preservation of the Schneiderian membrane periosteal layer. Twelve patients underwent a sinus graft via lateral approach during the years 2004-2012. Simultaneous APC removal was achieved through a small additional bony access, preserving the integrity of the periosteal layer of the Schneiderian membrane. Nineteen implants were inserted at the time of sinus augmentation or during a second stage. Prosthetic rehabilitation was started at 4-6 months after implant placement. No patient developed surgical complications or APC recurrence. The survival rate of implants and related prostheses was 100% over a mean follow-up of 50 months (range 12-96 months) after completion of the prosthetic restorations. This technique may represent an effective procedure to achieve APC removal at the time of sinus grafting, preserving the integrity of the Schneiderian membrane periosteal layer.

Computation of tooth axes of existent and missing teeth from 3D CT images.

Orientations of tooth axes are important quantitative information used in dental diagnosis and surgery planning. However, their computation is a complex problem, and the existing methods have respective limitations. This paper proposes new methods to compute 3D tooth axes from 3D CT images for existent teeth with single root or multiple roots and to estimate 3D tooth axes from 3D CT images for missing teeth. The tooth axis of a single-root tooth will be determined by segmenting the pulp cavity of the tooth and computing the principal direction of the pulp cavity, and the estimation of tooth axes of the missing teeth is modeled as an interpolation problem of some quaternions along a 3D curve. The proposed methods can either avoid the difficult teeth segmentation problem or improve the limitations of existing methods. Their effectiveness and practicality are demonstrated by experimental results of different 3D CT images from the clinic.