Implant materials, design, and surface topographies: their influence on osseointegration of dental implants

The purpose of this review is to describe commonly used dental implants with reference to their material composition, design factors, and surface topographies. The review includes a discussion of the biological principle of osseointegration and how this process of bone-implant interaction is influenced by different implant materials, designs, and surface characteristics

Effect of implant design on survival and success rates of titanium oral implants: a 10-year prospective cohort study of the ITI Dental Implant System

AIM

The aim of this 10-year study (observation time 8-12 years, mean: 10 years) was to compare the survival rates, success rates and incidences of biological complications using three different implant designs of the ITI Dental Implant System.

MATERIAL AND METHODS

In 89 dental patients treated comprehensively, a total of 112 hollow screw (HS), 49 hollow cylinder (HC) and 18 angulated hollow cylinder (AHC) implants were installed depending on the available bone volume and according to prosthetic needs. One and 10 years after surgical placement, clinical and radiographic parameters were assessed. The incidences of peri-implantitis according to various thresholds were registered over 10 years of maintenance.

RESULTS

Success criteria at 10 years were set at: pocket probing depth (PPD)< or =5 mm, bleeding on probing (BoP)-, bone loss < 0.2 mm annually. The survival rate for HS was 95.4%, for HC 85.7% and for AHC 91.7%. Ninety percent of all the HS, 71% of the HC and 88% of the AHC did not present with an incidence of peri-implantitis over the 10 years, HC having significantly higher incidence of peri-implantitis than HS (P< 0.004). With the success criteria set above, a success rate for HS of 74%, for HC of 63% and for AHC of 61% was identified at 10 years. However, including a definition of PPD< or =6 mm, BoP - and bone loss < 0.2 mm annually for success, the rates for HS were 78%, for HC 65% and for AHC 67%, respectively. Basing success criteria purely on clinical parameters (without radiographic analysis), such as: PPD< or =5 mm and BoP-, the success rates increased to 90%, 76% and 89%, respectively. With PPD< or =6 mm and BoP - as success criteria chosen, the respective rates were 94%, 82% and 94% for HS, HC and AHC implants, respectively.

CONCLUSIONS

A significantly higher survival rate as well as a significantly lower incidence of peri-implantitis was identified for hollow screw design ITI Dental Implants after 10 years of service when compared to hollow cylinder design ITI Dental Implants (95.4% vs. 85.7%; 10% vs. 29%). Depending on the setting of the threshold criteria for success, success rates are highly variable and hence, reporting of success rates with elaboration on the criteria set appears crucial for comparison of different studies.

Effect of GBR and fixture installation on gingiva and bone levels at adjacent teeth

Guided bone regeneration (GBR) is frequently used in oral implantology. It is unclear to what extent GBR affects the periodontium of adjacent teeth. Therefore, the present study quantifies changes in the proximal gingiva and bone levels at these teeth in 30 patients. Staged surgery involved a standard GBR treatment, randomly using resorbable membranes with a bone substitute or non-resorbable membranes with or without a bone substitute, followed by fixture installation at 6 months and abutment connection a further 6 months later. The data were sampled at each surgery and analysed using MANOVA. Twelve months after GBR, there was on average a small but statistically significant amount of proximal gingival recession (0.75 mm) and bone resorption (0.34 mm) observed, of which 50% was the result of GBR surgery. No significant differences were found between the different GBR treatment modalities. It is concluded that GBR treatment may have a small negative effect on the levels of the free gingival margin and alveolar bone at adjacent teeth, which is in most patients not clinically relevant.

Complications of mandibular molar replacement with a single implant: a case report

This case report describes prosthodontic complications resulting from the surgical placement of a single implant and treatment following these complications. Both the surgical and prosthodontic procedures are described for the treatment of a 57-year-old man who had previously received a single implant for the replacement of a missing molar. Using 2 implants, 1 mesial and 1 distal to the previously placed single implant proved reliable. A logical treatment solution is to use 2 implants for the replacement of a single molar to avoid prosthodontic complications.

[Risk factors for dental implant inflammation--a literature review]

Replacing missing teeth with osseointegrated dental implants is a predictable technique as evidanced by overall 5-years survival rate that range between 93% to 97%. Few studies, however have adressed the history and frequency of inflammatory complication associated with dental implant. Inflammatory complications are the main cause of failure of dental implants. In this review we classified the inflammatory complications to acute and chronic and to those limited to the hard tissue, to the soft tissue or both. The incidence of the complications is discussed with an emphasis on their risk factors.

The Prevalence of Surgical Complications of the Sinus Graft Procedure and Their Impact on Implant Survival

BACKGROUND

Grafting of the maxillary sinus floor has been performed successfully over the last decade. The ultimate goal of this procedure is to allow surviving implants to support a functional prosthesis. Surgical complications of the procedure are rarely reported and their impact on implant survival has been investigated even to a lesser extent. The purpose of this study was to evaluate the prevalence of surgical complications of the sinus graft procedure and their impact on implant survival.

METHODS

The study consisted of 70 patients who underwent 81 sinus graft procedures using the lateral wall approach from 1995 to 2000. A total of 212 screw-shaped implants were placed in the grafted sinuses and were restored by fixed prosthesis. Mean follow-up period for the implants was 43.6 months. Intra- and postoperative complications were thoroughly documented regarding clinical signs, times of occurrence, and treatment regimens.

RESULTS

Perforation of the Schneiderian membrane was the major intraoperative complication, observed in 36 of the 81 sinuses (44%). Of the 70 patients, seven (10%) suffered from postoperative complications, specifically related to the sinus graft procedure, which included an uncommon cyst formation and an infection. Membrane perforations were strongly associated with the appearance of postoperative complications (specific and non-specific to the procedure) (P < 0.001). However, no association was found between membrane perforations or postoperative complications and implant survival.

CONCLUSIONS

Intraoperative complications may lead to postoperative complications. Surgical complications did not significantly influence implant survival.

Initial Implant Position Determines the Magnitude of Crestal Bone Remodeling

BACKGROUND

The ability to predict the amount of bone remodeling around implants is important for a stable and predictable esthetic result. The purpose of this study was to investigate the amount of radiographic bone remodeling that occurs over time using a one-piece implant system.

METHODS

Twenty-seven patients receiving implants in the maxilla and 15 receiving implants in the mandible were included in the study. All implants were placed with a non-submerged surgical technique with varying locations of the rough-smooth border with respect to the alveolar crest. Clinical exams and radiographs were taken on the day of implant placement, at 6 months, and annually up to 5 years. Linear measurements from digitized radiographs were made from the implant shoulder to the first bone-to-implant contact at all time points.

RESULTS

A significant amount of bone remodeling compared to baseline occurred for all implants at the 6-month follow-up visit (1.10 mm), with the remaining time points showing virtually no change (0.1 mm). A relationship was found between the amount of bone remodeling and the location of the rough-smooth border with respect to the alveolar crest. Those implants with the rough-smooth border surgically placed below the crest had, on average, a greater amount of remodeling at 6 months (average 1.72 mm) than implants with the rough-smooth border placed at or near the crest (average 0.68 mm). In both situations, this remodeling: 1) occurred early (within 6 months), 2) reached a similar level, and 3) remained virtually unchanged up through 60 months (0.05 mm).

CONCLUSIONS

A physiologic dimension appears to exist between the bone and the implant-crown interface around one-piece implants that is established early and maintained over time. These results are significant because they demonstrate in patients that the magnitude of initial bone remodeling around these one-piece dental implants is dependent on the positioning of the rough-smooth border of the implant in an apico-coronal dimension. Furthermore, the dimension, from the crown-implant interface to the first bone-to-implant contact, is consistent with the formation of a biologic width similar to that found around the natural dentition.

Retrospective evaluation of the success of oral rehabilitation using the Frialit-2 implant system. Part 1: Influence of topographic and surgical parameters

PURPOSE

This retrospective longitudinal study evaluated the success of implant-prosthetic rehabilitation with the Frialit-2 implant system.

MATERIALS AND METHODS

The study was performed with 504 patients, from two treatment centers, who had received a total of 1,554 implants between May 1990 and May 2001. The data of these patients, who received the implants in various regions and for various indications, were analyzed with respect to clinical, topographic, and radiographic parameters. The mean observation period was 6.2 years, with a maximum of 134 months.

RESULTS

A survival rate of 94.8% was found for all implants. The implant survival rate of 92.6% in the maxilla remained constant after 68 months of observation. In the mandible, the implant survival rate of 96.7% showed no changes after 76 months. Kaplan-Meier analysis identified jaw, occurrence of postoperative complications, and region as statistically significant factors influencing implant survival. Multivariate Cox regression showed that gender, occurrence of postoperative complications, and jaw were factors that increased the risk of implant loss. Statistically significant correlations were found between the incidence of implant loss and vertical bone loss adjacent to the implant at the time of second-stage surgery.

CONCLUSION

Implant survival rate is influenced by implant site, gender, and occurrence of complications. On the whole, the Frialit-2 system proved successful in all areas of indication after long-term observation.

Histomorphometrical and clinical comparison of submerged and nonsubmerged implants subjected to experimental peri-implantitis in dogs

OBJECTIVES

Soft and hard tissue healing around submerged and nonsubmerged versions of one dental implant design was evaluated in an experimental canine peri-implantitis model.

MATERIAL AND METHODS

Forty-eight c.p. Ti-implants with integrated (one-piece=OPI) or screw-on (two-piece=TPI) abutments were inserted in edentulous mandibles of eight beagle dogs, one OPI and one TPI with connected abutments for nonsubmerged and one TPI without abutment (SMI) for submerged healing. After 3 months, all implants were functionally loaded, and at 4 months peri-implantitis was ligature-induced in one jaw side. Intravital polyfluorochrome labeling, monthly conventional radiography and gingival probing of all 48 implants were performed until sacrifice 8 months postimplantation. Undecalcified ground sections in the bucco-lingual and mesio-distal planes of four dogs (23 implants, one implant lost) were evaluated by light and fluorescence microscopy. The immunohistochemical and SEM-vascular corrosion cast results of the four other dogs (24 implants) will be reported elsewhere. Levels of alveolar bone-to-implant contact (ABICL), alveolar crest (ACL) and junctional epithelium-to-implant contact were determined by computer-assisted histometry. Peri-implant alveolar bone loss (=saucerization) was assessed on the radiographs and calculated as ACL minus ABICL from histometric data.

RESULTS

Around SMIs and OPIs without ligature less plaque adhesion and lower gingival indices were found when compared to TPIs. Radiologically, all ligatured, but also some nonligatured implants showed alveolar bone loss. Histometry demonstrated reduced ABICL around all these implants. Saucerization was more pronounced on the lingual and mesio-distal sides. Particularly around TPIs, bone resorption was still active or bone formation was impaired on fluorochrome labeling. Only around SMIs and one OPI without ligature continuing alveolar bone formation reflected by gains in ABICL were found.

CONCLUSION

The clinical and histometric results of this study demonstrate that healing of submerged SMIs was not impaired by the two-stage procedure, resulting in equally good healing as around nonsubmerged OPIs. However, peri-implantitis plaque-induced by ligature and/or dilated abutment connection microgaps in TPIs affected alveolar bone-to-implant contacts more than transmucosal or submerged healing mechanisms.

Association between periodontal and peri-implant conditions: a 10-year prospective study

OBJECTIVES

The aims of this study were to (1) compare prospectively the clinical and radiographic changes in periodontal and peri-implant conditions, (2) investigate the association of changes in periodontal parameters and peri-implant conditions over a mean observation period of 10 years (8-12 years) after implant installation, and (3) evaluate patient risk factors known to aggravate the periodontal conditions for their potential influence on the peri-implant tissue status.

MATERIALS AND METHODS

Eighty-nine partially edentulous patients with a mean age of 58.9 years (28-88 years) were examined at 1 and 10 years after implant placement. The patients contributed with 179 implants that were placed after comprehensive periodontal treatment and restored with crowns or fixed partial dentures. One hundred and seventy-nine matching control teeth were chosen as controls. Also, the remaining teeth (n=1770) in the dentitions were evaluated. Data on smoking habits and general health aspects were collected at 1 and 10 years as well.

RESULTS

At 10 years, statistically significant differences existed between implants and matching control teeth with regard to most of the clinical and radiographic parameters (P<0.01) with the exception of plaque index (PII) and recession. Multiple regression analyses were performed to associate combinations of periodontal diagnostic parameters to the peri-implant conditions: probing attachment level (PAL) at implants at 10 years was associated with implant location, full-mouth probing pocket depth (PPD) and full-mouth PAL (P=0.0001, r2=0.36). PPD at implants at 10 years correlated to implant location, full-mouth PPD and full-mouth PAL (P<0.001, r2=0.47). Marginal bone level at implants at 10 years was significantly associated to smoking, general health condition, implant location, full-mouth PAL and change over time in full-mouth PPD (P<0.001, r2=0.39).

CONCLUSIONS

These results present evidence for the association between periodontal and peri-implant conditions and the changes in these tissues over 10 years in partially edentulous patients.

Sublingual hematoma formation during immediate placement of mandibular endosseous implants

BACKGROUND

Sublingual hematoma during placement of mandibular endosseous dental implants is a rare, but potentially life-threatening, complication. The development of a sublingual hematoma during a dental procedure may result in the need for acute airway management, including intubation or even emergent tracheostomy. Dental implants are becoming a well-accepted treatment, and thousands of implants are placed every year by general practitioners and specialists, with few adverse sequelae. Clinicians rarely discuss this complication with patients before surgery, and no reports of death secondary to sublingual hematoma formation have been published. The incidence of this event is difficult to ascertain, and only, a few cases have been reported.

CASE DESCRIPTION

A 56-year-old man with severe caries underwent multiple mandibular tooth extractions and alveoloplasty and received endosseous implants. During the surgical procedure, the patient developed a large sublingual hematoma that required hospitalization.

CLINICAL IMPLICATIONS

Practitioners who perform implant surgery in the anterior mandible should notify patients of the potential risk of sublingual hematoma formation, and be able to manage acute airway issues that may result from this complication.

Alveolar distraction osteogenesis vs. vertical guided bone regeneration for the correction of vertically deficient edentulous ridges: A 1-3-year prospective study on humans

The purpose of this prospective study was to compare vertical guided bone regeneration (GBR) and vertical distraction osteogenesis (DO) for their ability in correcting vertically deficient alveolar ridges and their ability in maintaining over time the vertical bone gain obtained before and after implant placement. Eleven patients (group 1) were treated by means of vertical GBR with autogenous bone and e-PTFE membranes, while 10 patients (group 2) were treated by means of DO. In group 1, six patients received implants at the time of GBR (subgroup 1A), while five patients had implants placed at the time of membrane removal (subgroup 1B). In group 2, implants were placed at the time of distraction device removal. A total of 25 implants were placed in group 1 and 34 implants were placed in group 2 patients. Three to 5 months after implant placement, patients were rehabilitated with implant-borne dental prostheses. The following parameters were evaluated: (a) bone resorption of the regenerated ridges before and after implant placement; (b) peri-implant clinical parameters 1, 2, and 3 years after prosthetic loading of implants; (c) survival and success rates of implants. Bone resorption values before and after implant placement were significantly higher in group 1. The results suggested that both techniques may improve the deficit of vertically resorbed edentulous ridges, although distraction osteogenesis seems to be more predictable as far as the long-term prognosis of vertical bone gain is concerned. Implant survival rates as well as peri-implant clinical parameters do not differ significantly between the two groups, whereas the success rate of implants placed in group 2 patients was higher than that obtained in group 1 patients.

Surgical treatment of peri-implantitis

Surgical treatment of peri-implantitis lesions can be performed in cases with considerable pocket formation (larger than 5 mm) and bone loss after the acute infection has been resolved and proper oral hygiene has been instituted. A literature review was conducted to ascertain current knowledge about surgical treatment options for peri-implantitis around commercially pure titanium implants. Recently reported animal studies involving implants with a rough surface indicate that considerable bone regeneration and re-osseointegration can be obtained by using membrane-covered autogenous bone graft particles. However, comparisons of the treatment outcomes in studies involving humans and animals are difficult because of differences in implant type, graft type, and evaluation protocols. In addition, different treatment procedures, including implant surface decontamination methods, have been used. Therefore, further long-term studies in humans involving sufficient numbers of subjects are needed to provide a solid basis for recommendations regarding the surgical treatment of peri-implantitis. Moreover, the encouraging treatment outcomes of regenerative procedures recently revealed in animal experiments and applied in the treatment of peri-implantitis around implants with sandblasted/acid-etched surfaces have not yet been documented for implants with other surfaces, especially turned surfaces. Numerous implant surface decontamination methods have been suggested as part of the surgical treatment of peri-implantitis. Decontamination of affected implants with titanium plasma-sprayed or sandblasted/acid-etched surfaces may most easily and effectively be achieved by applying gauze soaked alternately in chlorhexidine and saline.

Diagnostic parameters for monitoring peri-implant conditions

PURPOSE

To review the literature on clinical, radiographic, and biochemical parameters used for monitoring peri-implant conditions.

MATERIALS AND METHODS

A MEDLINE search was conducted that included articles published in English until the end of August 2003. Results from human and experimental animal studies are presented.

RESULTS

The parameters that may be used to assess the presence of peri-implant health and the severity of peri-implant disease include plaque assessment, mucosal conditions, peri-implant probing depth, width of the peri-implant keratinized mucosa, periimplant sulcus fluid analysis, suppuration, implant mobility and discomfort, resonance frequency analysis, and radiographic evaluation.

DISCUSSION

Based on the analysis of the available evidence, it appears reasonable to use a number of clinical and radiographic parameters to discriminate between peri-implant health and disease.

CONCLUSIONS

Systematic and continuous monitoring of peri-implant tissues during maintenance care is recommended for the early diagnosis of peri-implant disease.

Antimicrobial treatment of peri-implant diseases

PURPOSE

To review the literature on the treatment of peri-implant diseases. Specific emphasis was placed on the use of antimicrobial therapy, defined as local or systemic administration of antiseptic and/or antibiotic agents.

MATERIALS AND METHODS

A search of MEDLINE, the Cochrane Controlled Trials Register, and The Cochrane Health Group Specialized Register was conducted, and articles published in English until July 31, 2003, were included. The results of experimental animal studies and human research are presented.

RESULTS

A variety of antimicrobial treatment regimens in combination with nonsurgical or surgical debridement with and without regenerative therapy were reported. Use of antimicrobials varied between studies with respect to type of drug, dosage, delivery system, duration, and commencement of antibiotic administration. Patient compliance and adverse effects related to the antimicrobials were mostly not mentioned.

DISCUSSION

While the majority of the case reports and studies presented showed positive outcomes following antimicrobial treatment, there were no non-medicated controls included, so the relative effect of the antimicrobial agent(s) cannot be evaluated.

CONCLUSIONS

Although antimicrobials are widely used for the treatment of peri-implant diseases, evidence of their benefit is limited, and randomized, controlled human trials should be initiated where ethically possible. In addition, prospective cohort studies designed to monitor consecutive cases treated using specific treatment protocols are required.

Contemporary implant concepts in aesthetic dentistry--Part 2: Immediate single-tooth implants

Immediate implant placement and provisionalization in the aesthetic region has demonstrated predictable long-term results. Use of the immediate loading protocol significantly reduces the need for a second surgical intervention following implant placement. Based on the patient's preoperative condition, this technique can also be incorporated in select cases without the need for complicated bone grafting and augmentation procedures in compromised ridges. This article discusses the placement of single-tooth implants in the anterior region and presents the advantages and limitations of the immediate placement protocol.

A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage

PURPOSE

The aim of this prospective clinical study was to assess the risk factors associated with failure of mini-implants used for orthodontic anchorage.

MATERIALS AND METHODS

A total of 140 mini-implants in 44 patients, including 48 miniplates and 92 freestanding miniscrews, were examined in the study. A variety of orthodontic loads were applied. The majority of implants were placed in the posterior maxilla (104/140), and the next most common location was the posterior mandible (34/140).

RESULTS

A cumulative survival rate of 89% (125/140) was found by Kaplan-Meier analysis. There was no significant difference in the survival rate between miniplates and freestanding miniscrews, but miniplates were used in more hazardous situations. The Cox proportional-hazards regression model identified anatomic location and peri-implant soft tissue character as 2 independent prognostic indicators. The estimated relative risk of implant failure in the posterior mandible was 1.101 (95% confidence interval, 0.942 to 1.301; P = .046). The risk ratio of failure for implants surrounded by nonkeratinized mucosa was 1.117 (95% confidence interval, 0.899 to 1.405; P = .026).

DISCUSSION AND CONCLUSION

The results confirmed the effectiveness of orthodontic mini-implants, but in certain situations adjustment of the treatment plan or modifications in the technique of implant placement may lead to improved success rates.

Periodontal Parameters Around Implants Anchoring Orthodontic Appliances: A Series of Case Reports

BACKGROUND

Implants replacing missing teeth provide advantages over clinical orthodontic treatment as compensation for reaction forces is no longer necessary and the lack of teeth is immediately resolved.

METHODS

A total of 38 two-stage implants were inserted (16 in maxilla, 22 in mandible) in 10 partially edentulous patients with orthodontic problems. Osseointegration and marginal bone levels were assessed via intra-oral radiographs taken at the abutment stage and at the completion of the orthodontic treatment and also via probing depth, measurement of recession toward the implant/abutment (I/A) interface, and sulcus bleeding index, recorded after completion of orthodontic treatment.

RESULTS

In the maxilla, the cumulative survival rate was 87.1% after 2 years; for the mandible, it remained 100%. Mean amount of bone loss was 1.6 mm for maxilla and 0.8 mm for mandible. No correlation could be found between directions of orthodontic forces and marginal bone loss. Mean percentage of bleeding sites was 38.5% and 25%, respectively, for implants in the maxilla and mandible. Attachment level was 1.2 mm (SD: 1.2) below I/A interface after completion of the orthodonic treatment.

CONCLUSION

No significant marginal bone loss was present. Using implants during orthodontics can result in an easier and more predictable treatment.

Periimplantitis

Orodental rehabilitation through the use of implants offers very high success rates. In this paper, we describe some of the complications involved with this technique, such as periimplant disease and, within this category, periimplantitis, an inflammatory reaction in which there is a loss of the bony support of the implant accompanied by inflammation. The aetiology of the disease is conditioned by the status of the tissue surrounding the implant, implant design, degree of roughness, the poor alignment of implant components, external morphology and excessive mechanical load. The microorganisms most commonly associated with implant failure are spirochetes and mobile forms of Gram-negative anaerobes, unless the origin is the result of simple mechanical overload. Diagnosis is based on changes of colour in the gum, bleeding and probing depth of periimplant pockets, suppuration, x-ray and gradual loss of bone height around the tooth. Treatment will differ depending upon whether it is a case of mucositis or periimplantitis. Therapeutic objectives focus on correcting technical defects by means of surgery and decontamination techniques (abrasion with carbon particles, citric acid solution, topical tetracycline application and laser surgery). This study also presents a microbiological study of periimplantitis conducted by the Barcelona School of Dentistry that determined that the antibiotic therapy proven to be most efficacious in the antibiogram was the association of amoxycillin and clavulanic acid.