OBJECTIVETo study the precise stress distribution of the apical foramen area of endodontic endosseous implant, in order to improve the prosthetics of endodontic endosseous implant.

METHODSAfter analysis of the two-dimensional endodontic endosseous implants model with finite element method, left and right areas beside the apical foramen were selected as infinite domains to calculate. D-N interactive method was used to connect the finite and infinite domains.

RESULTSUnder 45 degrees axial right oblique loading, the stress concentration occurred in both infinite domains of the apical foramen. The infinite domain nearing the load side was tension stress concentration, but the other side was compressive stress concentration. Two stress concentration points were just at the central points, which were intersections between implant and dentin. The stress reduced in all directions from these two stress concentration points, but in the ligament, the result was contrary.

CONCLUSIONSThe change of the tooth rotational center is helpful to the tooth stability and carrying capacity after restoration. In the implant area, the diameter of implant at the apical foramen of root shall not be reduced to protect root in clinical work. It is very important to preserve the tissue of periodontal ligament for endodontic endosseous implants.

Dental Implantation, Endosseous ; Dental Models ; Dental Stress Analysis ; methods ; Humans

OBJECTIVETo investigate the osteointegration of with self-drilling and self-tapping microscrew implants under immediate loading histomorphometrically.

METHODSThe buccal side of upper and lower jaws of three dogs was chosen as implant receipt site. Each dog accepted 8 implants (4 self-drilling and 4 self-tapping implants). Approximately 1.47-1.96 N continuous and constant forces were immediately applied between two microscrew implants with nickel-titanium coil spring for 9 weeks. Undecalcified sections of implants and surrounding tissue were studied with light microscope and fluorescent microscope.

RESULTSOsteointegration was seen in all samples and no fibrous tissue was seen between bone and implant. More original bone was seen in self-drilling group. Modeling and remodeling were more active in self-tapping group. Bone-to-implant contact values were statistically significant higher in self-drilling group [(41.7 +/- 10.7)%] than in self-tapping group [(25.9 +/- 8.0)%, P<0.01].

CONCLUSIONSImmediate loading had no influence on osteointegration in both self-drilling and self-tapping groups. The rates of bone-to-implant contact were higher in self-drilling group.

Animals ; Dental Implantation ; methods ; Dental Implantation, Endosseous ; Dental Implants ; Dogs ; Female ; Orthodontic Anchorage Procedures ; Osseointegration

Dental Implantation, Endosseous ; methods ; Dental Implants ; Dental Prosthesis, Implant-Supported ; methods ; Humans ; Surgery, Computer-Assisted

Dental Implantation, Endosseous ; methods ; Dental Implants ; Dental Restoration Failure ; Denture, Complete, Immediate ; Humans ; Jaw, Edentulous ; surgery

Alveolar Process ; surgery ; Dental Implantation, Endosseous ; methods ; Esthetics, Dental ; Gingiva ; surgery ; Humans

When selecting implant guidance methods or judging whether the patient can be implanted, many doctors ignore or only use visual inspection to estimate a patient's mouth opening. This phenomenon often leads to failure to complete the implantation due to insufficient mouth opening or the deflection of the implant due to limited angle, resulting in the high incidence of corresponding complications. The main reason is that doctors lack accurate analysis and control of the overall geometric conditions of the intraoral surgical area, and three-dimensional position blocking of surgical instruments occurs during the operation. In the past, mouth opening was defined as the distance between the incisor edges of the upper and lower central incisors when the patient opens his mouth widely, and the implant area could be in any missing tooth position. When it is in the posterior tooth area, the specific measurement scheme of the mouth opening could not be simply equivalent to the previous measurement method in the anterior tooth area. However, how to measure quickly and conveniently the mouth opening of any surgical area to determine whether it could be implanted and meet the needs of the selected guidance method remains unclear. This paper introduces new concepts, establishes new classification and corresponding accurate measurement scheme of implant area, and establishes a decision tree of implant methods guided by the actually measured value. Results provide a quantitative basis for rational formulation and implementation of implant treatment.
Humans ; Mouth ; Dental Implantation, Endosseous/methods* ; Incisor ; Clinical Decision-Making ; Dental Implants

Implant treatment in the esthetic area requires stable osseointegration and successful esthetic outcomes. Achieving this goal requires careful consideration of accurate implant axis and ideal three-dimensional position. Owing to the high esthetics and the special anatomical structure of the maxillary, a successful implant means a synthesized deli-beration of the residual bone dimensions, soft-tissue thickness, and the relationship of the residual alveolar ridge with the planned restoration. This article offers an in-depth analysis of the clinical decisions and key factors affecting the implant direction in the esthetic area.
Dental Implantation, Endosseous/methods* ; Dental Implants ; Esthetics, Dental ; Alveolar Ridge Augmentation/methods* ; Osseointegration ; Maxilla/surgery* ; Dental Implants, Single-Tooth

OBJECTIVETo investigate the anatomical features of iliac bone grafts used for mandibular reconstruction and dental implantation.

METHODSSixteen cadavers were dissected. The length, width, height and cortical thickness of the iliac bone were measured with respect to points determined by the relative dimensions of the bone.

RESULTSThe length of iliac bone graft was (77.2 ± 6.1) mm. The height was from (38.2 ± 4.2) mm to (41.9 ± 4.7) mm. The width decreased from iliac crest to base line. The least width 10 mm and 15 mm away from iliac crest were (8.4 ± 2.2) mm and (6.5 ± 2.1) mm respectively. The greatest mean cross-sectional cortical thickness at the intermediate line of the iliac crest was (3.4 ± 0.8) mm.

CONCLUSIONSAnatomical features of iliac bone are suitable for designing bone grafts for mandibular reconstruction followed by dental implantation.

Bone Transplantation ; Dental Implantation, Endosseous ; methods ; Humans ; Ilium ; anatomy & histology ; transplantation ; Mandible ; surgery ; Mandibular Reconstruction ; methods

OBJECTIVETo establish anisotropic mandible model with dental implants and to investigate the effect of anisotropy material on stress and strain distribution of implant-bone interface.

METHODSThree-dimensional finite element models of whole mandible with anisotropic and equivalent isotropic material were created by CT scanning and universal surgical integration system (USIS) software developed by the authors. Two ITI threaded implants were implanted in the posterior teeth area. The values of principal stress and principal strain on the bone around dental implants were calculated in two different finite element models with buccolingual load.

RESULTSIn the anisotropic mandible model, nearly all values of the principal stress and principal strain on cortical and cancellous bone increased compared with the equivalent isotropy model, 2.1%-74.1% for principal stress and 4.7%-57.3% for principal strain, but 10. 3%-71.4% for principal stress and 19.5%-63.4% for principal strain on cancellous bone.

CONCLUSIONSIn the three-dimensional finite element analysis, anisotropic mandible model with dental implants has an apparent effect on the stress and strains of the implant-bone interface. Anisotropic mechanical properties of mandible should be emphasized in biomechanical study.

Dental Implantation, Endosseous ; methods ; Dental Implants ; Dental Prosthesis Design ; Dental Stress Analysis ; Finite Element Analysis ; Mandible ; Models, Anatomic ; Stress, Mechanical

OBJECTIVETo compare the stress distribution of the staggered and straight placement of implants in the mandibular posterior region.

METHODSUsing three-dimensional finite element approach to analyze the stress distribution and variance regularity under the localized load.

RESULTSUnder vertical load, the stress peak value reduced when wide implant was placed straight (min: 3.70 MPa), but slightly increased when normal implant was placed staggered (max: 8.32 MPa); under the inclined load from buccal to lingual direction, the stress peak value reduced when the wide implant was placed in straight line (min: 12.29 MPa) or normal implant was placed staggered with buccal offset configuration (min: 15.48 MPa), but increased with lingual offset configuration (max: 23.60 MPa).

CONCLUSIONSWide implant (> or = 4 mm) with straight placement should be adopted to reduce the stress peak value and improve stress distribution, when the buccolingual diameter of the alveolar ridge in the mandibular posterior region was wide.

Adult ; Dental Implantation, Endosseous ; methods ; Dental Prosthesis Design ; Dental Prosthesis, Implant-Supported ; Dental Stress Analysis ; Finite Element Analysis ; Humans ; Mandible