The custom implant impression coping: technical note

Unsupported soft tissue can collapse around a submerged implant or abutment head during the time interval between removal of the provisional prosthesis and placement of the impression material. A technique is described for accurately recording the implant or abutment position as well as the position of the soft tissue for a single tooth restoration using the provisional prosthesis as a custom implant impression coping.     

Influence of residual ridge resorption patterns on fixture placement and tooth position, Part III: Presurgical assessment of ridge augmentation requirements

Implant diagnostic methods using computed tomography with barium-coated templates have revealed the relationship between the optimal final tooth position and the residual alveolar process or ridge. While information with regard to emergence axis, anatomic limitations, fixture length, buccolingual cantilever, and prediction of the the final prosthetic design is available, presurgical information relating to the reconstruction potential of smile zone deformities remains elusive. The use of a complete provisional wax-up and the modification of a barium-coated template design can provide the implant team with presurgical information regarding the need for augmentation of hard tissue and soft tissue and the volume of tissue needed for reconstruction. This information can assist the implant team in the development of realistic treatment objectives and in more accurately addressing the needs and concerns of the patient during presurgical treatment planning.     

Hard-tissue augmentation for the placement of anterior dental implants

Dental implants have become a popular alternative for replacing missing teeth in every region of the oral cavity. In the anterior zone, special esthetic concerns require not only a stably anchored implant for long-term success, but also the presence of adequate hard and soft peri-implant tissues. Anterior tooth loss is often accompanied by considerable loss of alveolar bone, so augmenting hard tissue before or in combination with implant placement becomes a critical part of therapy. One of the most successful augmentation techniques is guided bone regeneration (GBR). Thus far, augmentation procedures using expanded polytetrafluoroethylene membranes (ePTFEa) have proved to be the most efficient and predictable surgical technique to enhance deficient bone sites. This article discusses some critical biological and clinical/technical aspects of GBR and describes techniques for anterior hard-tissue augmentation with the photographic documentations of three clinical cases.     

HLA-A towards a high-resolution DNA typing

PURPOSE: This study assessed the soft tissue changes produced by the placement of hard tissue replacement (HTR) polymer chin implants for augmentation genioplasty and evaluated the dimensional stability as well as any bony changes associated with the implants. PATIENTS AND METHODS: The study group consisted of 18 patients (3 males, 15 females) with an average follow-up of 21.5 months (range, 12 to 44 months). All implants were placed through an intraoral incision and stabilized to the symphysis with a single 2.0-mm diameter titanium screw. Preoperative, postoperative, and long-term cephalometric radiographs were analyzed for changes in soft tissue thickness in the chin region, implant stability, and the presence of bone resorption. RESULTS: The net hard tissue chin augmentation achieved averaged 6.0 mm (range, 4.5 to 9 mm). Average preoperative soft tissue thickness was 12.1 mm (range, 11 to 14.5 mm) and postoperatively it was 10.6 mm (range, 10 to 13.5 mm). The average increase in soft tissue projection was 77.6% (range, 71.4% to 83.3%) of the implant thickness. There was no radiographic evidence of implant migration or bony resorption beneath the implant. CONCLUSIONS: HTR implants appear to be a predictable means of augmenting the chin, providing the desired aesthetic change, without causing resorption of underlying bone.     

Single implant restorations: prosthetically induced soft tissue topography

An aesthetic transition from the smaller diameter of the implant to the prosthetic restoration that resembles the size of the natural tooth has presented an ongoing challenge to the implant restorative dentists. The appearance of the surrounding soft tissue is of major importance, and various techniques have been developed to guide and optimize its topography. The learning objective of this article is to present a cervical contouring concept, whereby the soft tissue topography is optimally determined already in the laboratory phase. Using a custom abutment and provisional crown as components of the transmucosal prosthetic unit (TPU), the topography is transferred to the vital intraoral tissues, which predictably adapt to the enhanced aesthetic configuration. Clinical cases are presented to demonstrate the sequence of the technique in treating the anterior region of the maxilla.     

Esthetic and prosthetic procedures in single-tooth replacement

Loss of anterior maxillary teeth always results in bone resorption and loss of interdental papillae, and the resorption makes a single tooth replacement by a dental implant very difficult. When infections have been present and the patient's history shows previous surgery at the apex of the root, bone destruction is substantial, which results in an increased resorption defect, thereby further increasing the aesthetic and prosthetic problems. This paper describes the steps necessary for implant surgery and the prosthetics; a brief summary is provided. The quality and quantity of bone, along with the space available between the adjacent teeth, are the basic factors in treatment planning and determine the type of implant to be used. Some resorption and bone defects are usually present after a tooth extraction, and bone regeneration procedures can be performed either before or simultaneously with the implant placement, with numerous flap designs available. Soft tissue augmentation can be achieved by taking a connective tissue graft from the palatal side. Antirotational devices (eg, hex lock abutments) are necessary for all implants in single tooth replacement. Screw-retained abutments can be used in posterior areas and in angled positions in facial areas as well. With proper single tooth implant position, cementation of laboratory fabricated crowns can be considered.     

Bone rehabilitation to achieve optimal aesthetics

Treatment involving oral implants has established a high success rate, including implant survival on a long-term basis. The challenge facing the clinicians today is to achieve an optimal long-term aesthetic result. To address this challenge, the volume of the underlying hard and soft tissue must be restored either prior to or simultaneously with the implant placement. The learning objective of this article is to review the critical biologic and clinical criteria essential in achieving a predictable success in aesthetic enhancement of the implant site. The article discusses the five phases of ridge reconstruction, utilization of bone grafts (with or without membranes), and the use of membranes alone. Soft tissue management and augmentation in aesthetic and nonaesthetic regions are differentiated and presented. Surgical complications are recognized as a clinical reality, and exposure of the membranes is evaluated and discussed. Four cases are used to describe and illustrate the clinical procedure.     

A comparison of the effect of different occlusal forms in mandibular implant overdentures

STATEMENT OF PROBLEM: Posterior tooth form selection for implant overdentures is made according to personal preference and experience using the concepts of conventional complete denture prosthodontics. PURPOSE: This study (1) compared the masticatory efficiency of three occlusal forms, 0 degrees, 30 degrees, and lingual contact (lingualized occlusion), in subjects with mandibular implant overdentures, and (2) determined their effects on the implant supporting tissues. MATERIAL AND METHODS: Eight patients who had four root form implants in the mandibular symphysis area connected with a Hader bar were selected. Maxillary and mandibular dentures were constructed for each patient with interchangeable posterior segments and the three occlusal forms were tested. The masticatory efficiency for each posterior tooth form was assessed with objective food tests and a subjective patient preference questionnaire. Periodic evaluation of implant-supporting tissues also was performed. RESULTS: Reliability analysis showed that all R1 coefficients were > or =0.80 (<0.001), indicating high subject consistency between multiple chewing efficiency trials. MANOVA analysis indicated a significant difference in chewing efficiency among the three occlusal forms (p < 0.001). The 0 degree occlusal form was associated with a significantly higher number of chewing strokes compared with 30 degrees or lingualized occlusal forms. The different occlusal forms were not found to have a clinically detrimental effect on the peri-implant soft or hard tissues. CONCLUSION: Chewing efficiency tests and patient preference ratings showed that 30 degree teeth and lingual contact provided better chewing efficiency than 0 degree teeth. None of the tested occlusal forms showed any clinical or radiographic detrimental effect on the implant-supporting tissues.     

Parental awareness of dental caries in toddlers

Endodontic endosseous implants stabilize teeth that have crown-root ratios compromised by periodontal disease, trauma, or apical resorption. By increasing the crown-root ratio, the implant improves the prognosis of the tooth, thus increasing its longevity. The purpose of this study was to evaluate, in vivo, the healing response to a newly introduced titanium endodontic implant. Eight implants were placed in the maxillary incisors and mandibular premolars of two adult beagle dogs after completion of root canal and osseous preparation. Peri-implant tissues were examined radiographically and histologically at 6 months postinsertion. Radiographically, the periapical area and tissue surrounding the implants seemed normal. Histologically, fibrous connective tissue and healthy bone intimately surrounded the implant. Epithelium or chronic inflammatory cells were not observed along the length of the implant. These findings suggest that titanium is a biocompatible metal when used as an endodontic endosseous implant.     

Implant reconstruction following removal of tumors of the head and neck

Functional maxillofacial rehabilitation following tumor ablation depends on many variables. These include the magnitude of hard or soft tissue defects, the use of adjunctive chemotherapy or radiation therapy, and the presence of underlying systemic disease. The physiologic effects of tumor ablation and radiation therapy on local tissues and grafted bone are discussed in this article in relation to the ultimate use of implant supported prostheses. Cases are presented to illustrate a variety of clinical situations.     

Dentoalveolar morphology: evaluation of natural root form versus cylindrical implant fixtures

The function of implant-supported restorations is now routinely achieved. As a result, the emphasis in restorative implant dentistry has shifted from function to aesthetics and the biocompatibility of the materials utilized. The learning objective of this article is to review the three major components essential to achieving natural aesthetics in implant-supported restorations--hard tissue dynamics, soft tissue dynamics, and dental aesthetics. Particular emphasis is directed to the dentoalveolar anatomy and morphology. Analysis of the tooth root morphology and dimensions has resulted in the design and fabrication of restorative components with dimensions that closely resemble the natural tooth anatomy and aesthetics. A system of transmucosal abutments has been designed, and its utilization is presented in this review.     

Effect of working conditions on vision in microcomputer users

Tooth wear is becoming more common in both adults and children. The triad of attrition, abrasion and erosion has been known for many years, but the contribution of erosion (irreversible loss of dental hard tissue due to a chemical process not involving bacteria, or the loss of tooth surface not directly associated with mechanical or traumatic factors or caries) to excessive loss of tooth tissue is now being emphasized. The authors of this paper examine the problem and suggest ways of overcoming it.     

The implant quality scale: a clinical assessment of the health--disease continuum

Implant success is as difficult to describe as the success criteria required for a tooth. A range from health to disease exists in both conditions. The primary criteria for assessing implant quality are pain and mobility. The presence of either one greatly compromises the implant, and removal is usually indicated. Probing depths may be related to the presence of local disease or pre-existing tissue thickness before the implant was inserted. An increasing probing depth is more diagnostic and signifies bone loss, gingival hyperplasia or hypertrophy. Bone loss is usually evaluated best with probing rather than with radiographs. The most common cause of bone loss during the first few years of function are exaggerated factors of stress. The bleeding index is easily observed and indicates inflammation of the gingiva. However, implant health status is not as related to sulcular inflammation as would be the case for a natural tooth. Implant failure is easier to describe and may consist of a variety of factors. Any pain, vertical mobility, uncontrolled progressive bone loss, and/or generalized periradiolucency warrant implant removal. Implant quality factors were established by James and modified by Misch into an implant quality scale which not only assesses the implant health-disease continuum, but relates treatment and prognosis to the existing conditions.     

The relationship between myenteric neuronal denervation, smooth muscle thickening and epithelial cell proliferation in the rat colon

The aim of the present experiment was to (i) study the healing after 3 and 7 months of bone defects filled with cancellous bovine bone mineral and (ii) compare the healing around implants placed in normal bone and in defects filled with bovine bone mineral. 5 beagle dogs, about 1-year-old, were used. At baseline, extractions of all mandibular left and right premolars were performed. Bone defects were prepared in the left mandibular quadrant. The defect was immediately filled with natural bovine cancellous bone mineral particles (Bio-Oss, Geistlich Sons Ltd. Wolhusen, Switzerland). No resective surgery was performed in the right jaw quadrant. In both quadrants the flaps were adjusted to allow full coverage of the edentulous ridge and sutured. 3 months later, 2 dogs (group I) were euthanized and biopsies from the premolar regions obtained and prepared for histologic analysis. The 3 remaining dogs (group II) were at this time interval (3 months) subjected to implant installation in the premolar region of both the right and left mandibular jaw quadrants. 2 fixtures of the ITI Dental Implant System (Straumann, Waldenburg, Switzerland; solid-screw; 8 x 3.3 mm) were installed in each side. The fixtures in the test side were placed within the previously grafted defect area, while the fixtures in the control side were placed in normally healed extraction sites. A 4 month period of plaque control was initiated. At the end of this period, a clinical examination including assessment of plaque and soft tissue inflammation was performed and radiographs obtained from the implant sites. Biopsies were harvested and 4 tissue samples were yielded per dog, each including the implant and the surrounding soft and hard peri-implant tissues. The biopsies were processed for ground sectioning or "fracture technique" and the sections produced were subjected to histological examination. The volume of the hard tissue that was occupied by clearly identified Bio-Oss particles was reduced between the 3- and 7-month intervals. This indicates that with time, Bio-Oss becomes integrated and subsequently replaced by newly formed bone. In other words, this xenograft fulfils the criteria of an osteoconductive material. It was also observed that 4 months after implant installation, the titanium/hard tissue interface at test and control sites exhibited, from both a quantitative and qualitative aspect, a similar degree of "osseointegration".     

Presurgical prosthetic management of the periodontal patient--a modern adhesive approach

The comprehensive management of the periodontal prosthetic patient requires that treatment be provided in a logical sequence; initial therapy, presurgical prosthetic management, surgical management of hard and soft tissue lesions, post-surgical prosthetics, followed by maintenance therapy. This article focuses on some of the most perplexing challenges encountered during the presurgical prosthetic management phase of periodontal diagnosis and therapy, including the stabilization of mobile teeth, the immediate replacement of teeth that require removal due to advanced attachment loss, and the correction of visual defects created by soft tissue loss. A number of creative treatment modalities are described that utilize silane-treated etched-glass fiber ropes and tapes (GlasSpan, GlasSpan, Inc.) for the internal reinforcement of periodontal splints and for the attachment of composite and natural tooth pontics as transitional tooth replacements. Gingival-colored composite (Gingiblend, Jeneric Pentron) and its importance as a diagnostic aid during the early stages of periodontal therapy and as an esthetic permanent restorative material are also examined.     

The application of deproteinized bovine bone mineral for ridge preservation prior to implantation. Clinical and histological observations in a case report

Alveolar ridge preservation following tooth extraction is important when implant-supported oral rehabilitation is considered. The ability to maintain the ridge allows implant placement in an ideal position, fulfilling both functional and esthetic demands. A deproteinized bovine bone mineral (DBBM) was used as a socket site filler material to maintain ridge configuration, without applying an occlusive membrane. The material was grafted and packed onto the socket sites immediately after extractions, and subsequently primary soft tissue closure was attempted. The ridge healed for 9 months before the second surgical procedure, in which the implant was placed. New bone formation was observed in all histological specimens. DBBM particles adhered to a highly osteocyte-rich woven and lamellar-type bone. Clinically and histologically, this report demonstrated DBBM particles to be an effective biocompatible filler agent in extraction sockets for ridge preservation prior to titanium fixture implantation. Randomized controlled clinical trials are needed to fully evaluate the usefulness of this material in ridge preservation after tooth extraction.     

The traumatic anterior overbite

The position of the anterior teeth and skeletal base relationship establish many of our facial characteristics, yet these same tooth positions can result in a range of dental problems that are often specific for a particular incisal relationship. Excessive loss of tooth tissue on various surfaces may result in trauma to the soft tissue and temporomandibular joint dysfunction. A range of treatment options may be required and can often be conveniently classified by the form of incisal relationship.     

Epinephrine in digital blocks: revisited

STATEMENT OF PROBLEM: Implant treatment in the United Kingdom has been provided mainly in specialist, regional dental hospitals. However, increasingly, general dentists are providing implant-supported prostheses in a private office setting. PURPOSE: This study investigated the nature, timing, and frequency of complications associated with single tooth implant therapy in a dental hospital and two dental offices. METHODS: The dental records of 58 patients provided with 76 implants during the period of 1989-95 were reviewed retrospectively. Fifty-three single tooth crowns on implants were placed by general dentists and 23 by specialists in the dental hospital. RESULTS: Implant survival rate was 96%. Twenty-eight guided bone regeneration procedures were required, including 13 unplanned ones. Prosthodontic complications included the need for recontouring of three crowns and the recementation of three crowns. Only two abutment screws required retightening. Peri-implant soft tissue inflammation occurred around six crowns and recession around two. CONCLUSION: The single tooth implant-supported crown appears to be an effective and durable restorative treatment with a relatively low prevalence of postoperative complications.     

Using sound dental principles to salvage the compromised implant case

Implant failure can usually be determined by biologic and biomechanical factors that were not addressed during treatment planing and case design. In order to salvage the failing implant-supported prosthesis, these factors must be identified and corrected. Long-term success can only be achieved when prosthetic design, osseous and soft tissue architecture, and implant biomechanics are diagnosed and corrected.     

Microgrooved subcutaneous implants in the goat

We investigated the behavior of microgrooved implants in soft tissue using polystyrene implantable disks, either smooth or microgrooved (1-10 microm) on both sides. The implants were placed subcutaneously in a goat for 1, 4, or 12 weeks. Light and transmission electron microscopy showed that fibrous capsule formation around the implants was fairly uniform. After 1 week the implants were covered with a fibrous capsule about 80 microm thick. The collagen matrix was loose, and many inflammatory cells were present. After 4 weeks the matrix was more dense and contained many newly formed blood vessels. At the implant surface a layer of inflammatory cells about 10 microm thick had accumulated. Finally, after 12 weeks the matrix had densified. One cellular layer of inflammatory cells was present at the implant surface. We carried out histomorphometric measurements of capsule thickness, inflammatory layer thickness, and the number of blood vessels. Capsule thickness appeared not to decrease with time. Further, these measurements showed that there were no differences in tissue reaction between smooth and microgrooved implants. On the basis of our observations, we suggest that 1 microm deep and 1-10 microm wide microgrooves do not influence tissue response around polystyrene implants in soft tissue.