The ideal axial orientation of implant is the key to the success of implant denture restoration. According to the restoration-oriented concept of implant, the implant axis direction should be consistent with the long axis direction of the suprastructure. In clinical practice, implant axial deviation leads to related complications, such as implant fracture, periimplant inflammation, and poor esthetic outcome of implant restoration, resulting in implant treatment failure. In this paper, complications related to improper implant axial orientation, their causes and treatment strategies are reviewed.
Dental Implants/adverse effects* ; Dental Prosthesis, Implant-Supported/adverse effects* ; Esthetics, Dental

Animals ; Dental Implantation, Endosseous ; adverse effects ; Dental Implants ; adverse effects ; Dental Prosthesis, Implant-Supported ; adverse effects ; Dentition ; Humans ; Malocclusion ; etiology ; Maxillofacial Development

OBJECTIVETo clarify the related factors of marginal bone loss (MBL) around tissue level implants in the posterior part of the mandible.

METHODSA total of 116 tissue level implants were implanted in the mandibular posterior region of 76 patients. Patients' information, including general characteristics, implant characteristics, implant site characteristics, and prosthesis characteristics, was recorded. Their cone beam computed tomography data were measured immediately after implant placement, 3 months later, and 3 and 12 months after prosthesis loading. The measurement of MBL was conducted by One Volume Viewer software. SPSS 20.0 was used for statistic analysis.

RESULTSSmoking, cortical bone thickness (CBT), collum angle (CA), and implant local sanitation showed significant differences with body mass loss (P<0.05). No significant differences were found among sex, age, length of implant, diameter of implants, implant systems, bone height, prosthesis type, and MBL (P>0.05).

CONCLUSIONThe risk factors that caused MBL were smoking, thicker CBT, larger CA, and poor implant local sanitation. Among them, poor implant local sanitation had the highest correlation with MBL.

Alveolar Bone Loss ; epidemiology ; etiology ; Cone-Beam Computed Tomography ; Dental Implants ; adverse effects ; Dental Prosthesis Design ; Dental Prosthesis, Implant-Supported ; Follow-Up Studies ; Humans ; Mandible ; Mandibular Prosthesis ; statistics & numerical data ; Oral Hygiene ; Postoperative Complications ; Smoking ; adverse effects ; Treatment Outcome

Alveolar Bone Loss ; prevention & control ; Alveolar Process ; surgery ; Bone Regeneration ; Dental Implantation, Endosseous ; Dental Prosthesis, Implant-Supported ; Guided Tissue Regeneration, Periodontal ; methods ; Humans ; Immediate Dental Implant Loading ; Male ; Middle Aged ; Periodontitis ; surgery ; Tooth Extraction ; adverse effects ; Wound Healing

OBJECTIVEPartial or full defects of jawbone following tumor resection frequently lead to a loss of mastication, an impaired speech function and a severe deformity of appearance. To improve the life quality of such patients, implantation or bone grafting-combined implantation was utilized to functionally reconstruct the jaw defects.

METHODS1. Fragmental or full mandibular defects were reconstructed by vascularized or non-vascularized bone grafts in combination with immediate or delayed implants. 2. The unilateral maxillary defect with an edentulous counter-side was rehabilitated by a prosthesis secured on implants placed on the healthy side. 3. For bilateral maxillary defect, implants were placed in the zygmatic bone or augmented zygmatic bone to support a prosthesis with magnetic retention.

RESULTS64 jaw defects (10 in maxilla; 54 in mandible) were reconstructed by three different methods to restore the appearance and functions. The longest follow-up period was 12 years and the shortest 5 year, only 6 implants were lost due to failure of osseointegration. The implant survival rate for the maxillary defects was 97.5%, for the mandibular defects with vascularized bone grafts was 97.1%, and with non-vascularized bone grafts was 97.7%.

CONCLUSIONSImplants-borne prosthesis is an applicable technique in restoration of maxillary defects. In case of insufficient zygomatic thickness, bone augmentation is often needed prior to implantation. As for the mandibular reconstruction, bone grafting in combination with implantation is an ideal method. Compared to non-vascularized bone grafting, the vascularized method is much more suitable for bone grafting beds with poor blood supply. From the practical point of view, non-vascularized bone graft in combination with implantation is more practicable. The reduced off-body time of bone grafts from donor to recipient site keeps most of osteoblasts vital and enables simultaneous implants to achieve osseointegration. This confirms the osteogenesis, osteoconduction and osteoinduction of bone autografts.

Adolescent ; Adult ; Aged ; Bone Transplantation ; Dental Prosthesis, Implant-Supported ; Female ; Humans ; Jaw Diseases ; etiology ; surgery ; Jaw Neoplasms ; surgery ; Male ; Mandible ; surgery ; Maxilla ; surgery ; Middle Aged ; Oral Surgical Procedures ; adverse effects ; Osseointegration ; Reconstructive Surgical Procedures ; methods ; Treatment Outcome

OBJECTIVETo compare the incidence of technical complications of implant-supported fixed dental prostheses in Chinese patients with a history of moderate or severe periodontitis and periodontally healthy patients(PHP) and analyze the effects of interproximal papillae patterns on food impaction and efficacy of plaque control.

METHODSA total of 103 partially edentulous patients treated with implant-supported fixed dental prostheses between December 2009 and December 2012 for a minimum 1-year follow-up period were recruited from Department of Periodontology, Peking University, School and Hospital of Stomatology. Based on the initial periodontal examination, the participants were divided into three groups: 30 PHP, 36 moderate periodontally compromised patients(mPCP) and 37 severe periodontally compromised patients(sPCP). Implant survival/loss, technical complications, plaque index, papilla index, food impaction and degree of proximal contact tightness of each patient were assessed around the implants at follow-up. According to the implant papilla index, the implants were divided into two groups: the "filling" group with the mesial and distal aspects with papilla index=3 and the "no filling" group with at least one aspect with papilla index<3. Data on implant survival, technical complications were analyzed. Comparisons of the incidence of technical complications were performed between the patients with different periodontal conditions with chi-square or Fisher's exact test. The influences of the interproximal papillae loss on food impaction and efficacy of plaque control were estimated with chi-square and Mann-Whitney U tests.

RESULTSThe total implant survival rate was 100%(162/162) for all three groups. Technical complications were as following: veneer fractures(1.9%, 3/162), abutment screw loosening(1.9%, 3/162), prosthetic screw loosening(3.1%, 5/162) and decementation(3.1%, 5/162) in all subjects. No implant/screw fracture was noted. The incidence of technical complications in sPCP, mPCP and PHP did not yield statistically significant differences(P>0.05). The proportion of the implant with the mesial and distal papilla index=3 in the sPCP was less than that in the PHP and mPCP. The interproximal papillae loss did not appear to affect the food impaction and the plaque index in all three groups(P>0.05). However, for the PHP, the accumulation of plaque at buccal aspect was more in the "no filling" group compared with the "filling" group (implant plaque index[M(Q)]: 1[1] vs 0[0]), and for the sPCP, the accumulation of plaque at lingual aspect was more in the "filling" group compared with the "no filling" group(implant plaque index[M(Q)]: 1[1] vs 0[1], (P<0.05).

CONCLUSIONSThe patients with a history of severe periodontitis did not exhibit more technical problems compared with the periodontally healthy patients. The interproximal papillae loss did not show a negative impact on the plaque control and food impaction. However, for the sPCP, changing the morphology and the position of the interproximal contact point to reduce the interdental black triangle may lead to accumulation of plaque at lingual aspect. More attention should be placed on the morphology design of prosthesis, but not the papillae filling up the interproximal space.

Beijing ; Dental Abutments ; Dental Implants ; Dental Plaque ; diagnosis ; etiology ; prevention & control ; Dental Plaque Index ; Dental Prosthesis, Implant-Supported ; adverse effects ; classification ; statistics & numerical data ; Dental Restoration Failure ; statistics & numerical data ; Follow-Up Studies ; Food ; Gingiva ; Humans ; Jaw, Edentulous, Partially ; rehabilitation ; Periodontal Diseases ; classification ; therapy