Surgical Restorative Decision Algorithm for Edentulous Condition in Implant Dentistry With Emphasis on Bone Augmentation.

Ridge preservation and bone augmentation techniques in implant dentistry are designed to preserve and augment existing alveolar ridge to prepare it for implant treatment. Bone stock is an essential component for a long-term success of dental implants. This article provides a prosthetically driven step-by-step surgical restorative decision tree algorithm to diagnose and treat an edentulous condition in implant dentistry.

Bone Augmentation Techniques for Horizontal and Vertical Alveolar Ridge Deficiency in Oral Implantology.

Bone deficiency is the major obstacle in implant dentistry. Guided bone regeneration (GBR) with particulate bone and barrier membranes has been the primary surgical technique used to regenerate alveolar bone for dental implant therapy. This procedure has been used in implant dentistry for more than 30 years and continues to be developed and refined for more predictable surgical outcomes. This article reviews GBR and alternative ride expansion procedures and reviews the use of various particulate graft materials. Alveolar distraction osteogenesis, used as an augmentation technique, is also presented.

Surgical Algorithm for Alveolar Bone Augmentation in Implant Dentistry.

Replacement of failing and ailing natural teeth with dental implants has become a mainstream treatment option since the discovery of osseointegration by P.-I. Brånemark in the 1960s. The techniques and the variety of methods for alveolar bone reconstruction have evolved to address a restoratively driven approach in implant dentistry. Modern 3D cone-bean computed tomography has helped with the diagnosis and treatment of bone deficiencies to idealize implant positioning. This article focuses on bone augmentation techniques, classified into horizontal and vertical ridge augmentation, and discusses block grafting, guided bone regeneration particulate grafting, distraction osteogenesis, and ridge-split expansion procedures.

Tuberosity-alveolar block as a donor site for localised augmentation of the maxilla: a retrospective clinical study.

Bone from the maxillary tuberosity has been harvested in particulate form to use for augmentation for several years, but block grafts have not been extensively used. A considerable advantage of a particulate bone graft from the maxillary tuberosity over those from other intraoral donor sites is the relative simplicity of harvesting and minimal complications. We have retrospectively assessed the efficacy of tuberosity-alveolar block bone (posterior maxillary alveolar ridge) in the augmentation of adjacent defects in the maxilla using data from 14 patients (10 men and four women, mean (range) age 55 (38-69) years) who had had 20 bony augmentations with block bone from the alveolar tuberosity during 2014. Patients were divided into three groups according to the technique by which the bone was collected. The first group had a graft from the alveolar tuberosity covered with titanium mesh (titanium mesh group); the second group had the block bone covered by platelet rich fibrin and collagen membrane (platelet rich fibrin group), and in the third group the graft was covered only with periosteum (periosteum group). The primary width of the bone was recorded at the time of placement of the graft and changes were evaluated 4-6 months later when the implant was inserted. The changes in the width of the bone were 4.1, 3.3, and 2.5 in the platelet rich fibrin, titanium mesh, and periosteum groups, respectively. The difference in bony change among groups was not significant except between the platelet rich fibrin and and periosteum groups (p=0.005). Tuberosity-alveolar block bone graft may be a good source of bone for augmentation of deficient ridges, and more favourable results can be expected by the addition of resorbable membranes and growth factors.

Is the angulation of mandibular third molars associated with the thickness of lingual bone?

To find out whether the angulation of mandibular third molars is associated with the thickness of the bone at the site of impaction, and if so, which particular angulation affects the protective mechanism of the nerve, we retrospectively studied the thickness of lingual bone at the sites of impaction of 200 mandibular third molars in 149 patients using coronal, sagittal, and axial slices of cone-beam computed tomograms (CT). We measured the bone at the cementoenamel junction of the mandibular second molar, at the mid-root of the third molar, and at the apex of the root. Bone less than 1mm thick was defined as "thinning". We correlated these measurements with the angulation of the tooth based on the position of the second molar and the occlusal plane in 3 dimensions: vertical, mesiobuccal, and buccolingual. The primary outcome was the thickness of the bone around the third molar. A total of 102 teeth were on the left (51%), and 125 were angulated with an occlusal plane of <85° (63%). The mean (SD) thickness of bone at the cementoenamel junction of the second molar was 1.40 (0.87) mm, at mid-root 1.07 (1.03) mm, and at the apex 1.07 (1.30) mm. When the horizontal and mesioangular angulations of teeth were <85°, the thickness of bone at the mid-root differed significantly from that when the vertical and distoangular angulations were 85° or more (p<0.001). Correlations between the thickness of the bone and the buccolingual angulations were significantly associated with perforation of the bone at mid-root and apex (p<0.003). The bone around horizontal and mesioangular impactions was 3.6 times more likely to be "thin" than that at mid-root of vertical and distoangular third molars. A buccolingual angulation was also associated with perforation of the lingual cortex (p<0.003). As the bone was thinner at the mid-root of horizontally and mesioangularly impacted teeth, it seemed to compromise the integrity of the lingual plate, which is the natural protective barrier of the lingual nerve. These findings could be of prognostic value.

Classification of the alveolar ridge width: implant-driven treatment considerations for the horizontally deficient alveolar ridges.

Among many techniques advocated for the horizontally deficient alveolar ridges, ridge-split has many advantages. Here, treatment management strategies of the horizontally collapsed ridges, especially the ridge-split approach, are discussed and a clinically relevant implant-driven classification of the alveolar ridge width is proposed, with the goal to assist an operator in choosing the proper bone augmentation technique. Comparison and advantages of two commonly used techniques, ridge-split and block bone graft, are presented.

Factors that are associated with injury to the inferior alveolar nerve in high-risk patients after removal of third molars.

Our aim was to answer the question: "Among patients at high risk of injury to the inferior alveolar nerve (IAN) after removal of 3rd molars, what factors are associated with postoperative neurosensory deficits?" We organized a retrospective, two-center study and enrolled a group of subjects who were at increased risk of injury to the IAN after removal of 3rd molars because radiographic findings indicated a risk on panoramic radiography that was high enough to warrant preoperative computed tomography (CT). The primary outcome variable was postoperative injury to the IAN. We used descriptive, bivariate, and multivariate analyses to assess the significance of differences, and probabilities of less than 0.05 were accepted as significant. We studied 149 subjects who had 235 3rd molars removed. Their mean (SD) age was 31 (11) years and 25/235 (11%) of 3rd molars were associated with injury to the IAN. In the multiple logistic regression model, increasing age (odds ratio (OR) 1.05, 95% CI 1.01-1.1, p=0.04), female sex (OR 5.3, 95% CI 1.6-16.9, p=0.005), and the size (mm) of the cortical perforation in the inferior alveolar canal (IAC) viewed on the coronal CT cut (OR 1.3; 95% CI 1.0-1.6, p=0.03) were associated with an increased risk of postoperative injury to the IAN. Age, sex, and the size of the perforation in the IAC on the coronal CT were associated with an increased risk of injury to the IAN. These findings may help to guide recommendations for treatment of patients at high risk of injury to the IAN during removal of 3rd molars.

Horizontal augmentation through the ridge-split procedure: a predictable surgical modality in implant reconstruction.

Among alveolar ridge augmentation techniques, the ridge-split procedure demonstrates many benefits, including no need for a second (donor) surgical site, rare risk of inferior alveolar nerve injury, and less pain and swelling, and others. Lateral bone augmentation through the ridge-split works best in a localized lateral bony defect intended for 1 or 2 implants and where the ridge is vertically intact. In this article, the authors present a detailed description of the implant-driven technique of alveolar ridge-split procedure in small and large bone deficiencies, in maxilla and mandible, supplemented by multiple photographs. The authors emphasize the need for careful manipulation of the thin ridge based on knowledge of precise surgical principles and stress that a practitioner needs specialized training and experience to perform this type of alveolar bone augmentation.

Implant-guided volumetric analysis of edentulous maxillary bone with cone-beam computerized tomography scan. Maxillary sinus pneumatization classification.

The primary goal of this anatomic study was to measure the average bone volume of the edentulous maxilla with a cone-beam computerized tomography (CBCT) scan and to determine its suitability for implant treatment without additional bone grafting. The secondary goal of the study was to estimate the degree of sinus pneumatization (SP) in reviewed CBCT scans, assess the sinus-to-maxillary bone interrelationship in edentulism, and attempt to classify maxillary sinuses based on the degree of their pneumatization. This retrospective radiographic quantitative study consisted of the analysis of CBCT scans of 30 randomly selected maxillary edentulous patients who presented in 2008-2010 to the University of the Pacific, Arthur A. Dugoni School of Dentistry, for evaluation and treatment of their edentulism. A volume of edentulous maxillary bone mesial to the maxillary sinuses (intersinal region) that can be used for a full-arch implant treatment was evaluated based on specifically selected and clinically relevant measurement criteria. There were 30 CBCT scans of maxillary edentulous patients reviewed (9 men, 21 women) with a mean age of 67.3 years (range, 41 to 92 years). The total mean maxillary bone volume (MMBV) suitable for implantation was 4 408.1 mm(3) and ranged from 1489.7 to 7263.1 mm(3). The MMBV in the study was higher than an assumed or hypothetical bone volume minimally suitable for 4-implant treatment as proposed by the authors for comparative purposes (3500 mm(3)). The degree of SP as seen on a CBCT scan (60 sinuses analyzed on panoramic images of 30 CBCT scans) had the following results in the study: SP0 (clear: not interfering with implant treatment in cases of high/small sinus), 2 sinuses or 3.3%; SP1 (mild sinus enlargement), 29 sinuses or 48.3%; SP2 (moderate SP), 16 sinuses or 26.7%; SP3 (severe SP), 9 sinuses or 15.0%; and SP4 (extreme), 4 sinuses or 6.7%. Most analyzed maxillary sinuses (47 of 60, or 78.3%) were in the clear, mild, or moderate categories of SP (SP0, SP1, and SP2), which have a sufficient amount of maxillary bone beneath the maxillary sinuses to allow a full-arch implant treatment. An inverse correlation between SP and MMBV was observed. Although many other clinical criteria are important (bone quality, alveolar crest anatomy, etc), the results of this CBCT radiographic study indicate that in many maxillary edentulous cases, the existing bone quantity (volume) can be sufficient for a full-arch maxillary implant treatment with at least 4 implants without the additional trauma or expense of bone grafts and sinus lifts. A variety of implant treatment options can be proposed based on maxillary bone availability and bone-to-sinus interrelationship. It appears that with age and edentulism, the amount of available maxillary bone is steadily decreasing.

Odontogenic osteomyelitis or bisphosphonate-related osteonecrosis of mandible of patient with autoimmune disease: clinical dilemma.

The key to appropriate treatment of odontogenic osteomyelitis or bisphosphonate-related osteonecrosis of the mandible in patients with autoimmune diseases lies in making the correct diagnosis based on meticulous review of signs and symptoms. As this complex case involving a patient with multiple comorbidities illustrates, diagnosis can be difficult, because these conditions may overlap or be mistaken for other conditions. However, prompt treatment is essential to limit the progression, which can be devastating for these medically complex patients. It is, therefore, important to understand local and systemic conditions that can weaken the immune system and predispose patients to chronic bone infection, meticulously go through signs and symptoms, and have a complete medical history, including patient medications.

Pericoronal ostectomy: an alternative surgical technique for management of mandibular third molars in close proximity to the inferior alveolar nerve.

PURPOSE: Close proximity of the inferior alveolar nerve (IAN) to mandibular third molars (MTMs) may result in nerve injury during the extraction of third molars. Alternative surgical techniques, such as coronectomy, have been suggested to decrease this risk. This study examined a new alternative technique, the pericoronal ostectomy (PO), that is intended to decrease IAN injury in high-risk cases. PATIENTS AND METHODS: This prospective clinical cohort study consisted of 14 patients with 17 MTMs in close relation to the IAN. All patients were subjected to 2- and 3-dimensional preoperative radiographic evaluations. Selected patients with mesioangular and vertical bone impactions were treated by the staged PO technique. An institutional review board approval from the University of the Pacific was given to this study. RESULTS: Because of the PO procedure, all 17 high-risk MTMs in the study erupted to a more occlusal position away from the danger zone of the IAN and were eventually removed (mean distance of eruption, 2.0 mm). Three patients reported a transient neurosensory deficit, 2 with the IAN and 1 with a lingual nerve. All 3 had a full resolution of symptoms within 3 months of the postoperative period. CONCLUSION: The PO technique appears to be an additional viable alternative technique to extraction of MTMs in intimate proximity to the IAN.