Tactile Sensibility of Single‐Tooth Implants and Natural Teeth Under Local Anesthesia of the Natural Antagonistic Teeth

Introduction and Aim: The term osseoperception describes the capability of developing a subtle tactile sensibility over dental implants. The present clinical study aims at clarifying the question of how far tactile sensibility is to be attributed to the periodontium of the natural opposing tooth of the implant. Material and Method: Thirty‐two subjects with single‐tooth implants with natural opposing teeth were included in this clinical, single‐blind, split‐mouth study. The natural antagonistic tooth of the implant and the corresponding natural contralateral tooth were anesthetized with a locally infiltrated articaine anesthetic. In a computer‐assisted and randomized way, copper foils of varying thickness (0–100 µm) were placed interocclusally between the single‐tooth implant and the natural opposing tooth, and between the contralateral pair of natural opposing teeth in order to investigate the active tactile sensibility according to the psychophysical method of constant stimuli and evaluate it statistically by the Weibull distribution. Results: The average tactile sensibility of the implants with anesthetized antagonists at the 50% value calculated by means of the Weibull distribution was 20 ± 11 µm with a support area (90%–10% value) of 77 ± 89 µm. For the pair of natural teeth, the tactile sensibility at the 50% value was 16 ± 9 µm with a support area of 48.4 ± 93 µm. This resulted in an average intraindividual difference of 3.5 ± 7 µm at the 50% value and 29 ± 93 µm in the support area. The statistical calculations demonstrated an equivalent tactile sensibility (50% value) of the single‐tooth implant and the contralateral natural control tooth with the natural antagonists being anesthetized in each case (double t‐test, equivalence limit ± 8 µm, P < 0.01, power >80%). Conclusion: Apparently, the active tactile sensibility of single‐tooth implants with natural opposing teeth is not only to be attributed to the periodontium of the opposing tooth but also to a perception over the implant itself. This could support the hypothesis according to which the implant may have a tactile sensibility of its own.     

A prospective 3-year study of fixed bridges linking Astra Tech ST implants to natural teeth

BACKGROUND: Connecting teeth and osseointegrated implants in fixed reconstructions is not generally recommended because of differences in their response to loading. AIM: The aim of the present study was to assess the clinical and radiographic performance of the teeth and implants used to support three unit fixed bridges subjected to normal functional loads. SUBJECTS AND METHODS: Nineteen subjects (10 males, nine females, age range 27-65 years) with an edentulous posterior free end saddle in either maxilla or mandible (Kennedy Class 2), and opposing natural teeth or a tooth-supported fixed bridge were treated and completed the 3-year trial. An Astra Tech ST implant (length: 9 mm (n=2), 11 mm (n=9) or 13 mm (n=8); diameter: 4.5 mm) was placed immediately distal to the last tooth or leaving a single premolar sized space. The distal tooth received a gold coping and the implant was restored with a customised Prepable abutment (Astra Tech Profile BiAbutment: diameter 5.5 or 7 mm). A fixed bridge was placed linking the gold coping and implant abutment either with the pontic as a distal cantilever (n=6, length 7-8 mm) or as a fixed-fixed design (n=13, length 6-12 mm). Standardised radiographs and clinical records were taken at delivery of the prosthesis (baseline BL) and annually. RESULTS: Plaque scores at implant sites increased between BL and subsequent years (P<0.02). Statistically significant increases in probing depth were observed at both abutment teeth and implants between baseline and subsequent years (P<0.001). Marginal bone levels (mm) at the implant and tooth were stable between BL, 1-, 2- and 3-year examinations (implant: BL 0.65+/-0.42, 1 year 0.63+/-0.47, 2 years 0.88+/-0.55, 3 years 0.78+/-0.64; tooth: BL 2.29+/-0.82, 1 year 2.41+/-0.8, 2 years 2.38+/-1.02, 3 years 2.68+/-0.86). No signs of the intrusion of the abutment teeth were detected. One case of abutment screw loosening occurred. Eight bridges required re-cementation with a permanent cement in place of the temporary cement. There were eight subjects presenting with fractures/chips to the composite component of the bridges. CONCLUSION: The 3-year results demonstrate fully functional successful restorations with no evidence of tooth intrusion and with stable bone levels at both teeth and implants.     

Influence of occlusal contacts of implant on adjacent teeth and antagonists displacements

This study examined the optimum occlusal contacts of implant prostheses to maintain good oral condition after treatment. Three subjects who had two contiguously missing teeth (first and second molars) were selected. The displacement path of the implant, the adjacent tooth and the antagonistic tooth during clenching were measured using the type M-3 three-dimensional tooth displacement transducer. The occlusal contacts of implant prostheses changed according to the following four conditions. A contact: the inner inclination of the upper buccal cusp, B contact: the inner inclination of the upper lingual cusp, C contact: the outer inclination of the upper lingual cusp, and ABC contact: including the above three contacts. The measurements were performed at least six months after implant surgery. In each subject, the implants and the adjacent teeth were not affected by the change of the occlusal contact of the implant prosthesis, but the opposing teeth were affected. In the case of implantation in the lower side, the opposing tooth displaced in the buccal direction with A contact and C contact, which was a different direction to that of the natural tooth. The antagonist with B contact displaced in the lingual direction, which was the same direction as that of the natural tooth. The antagonist with ABC contact displaced in the lingual or buccal direction. It is concluded that the occlusal adjustment of implants needs much care: in the case of only A contact or C contact, non-physiological distortion might occur in periodontal tissues of the opposing teeth of the implant.     

Gingival papilla dimensions in anterosuperior regions adjacent to single-tooth implants

This study compared the dimensions of gingival papillae in anterosuperior areas presenting at natural teeth (teeth sites) or single-tooth implants adjacent to natural teeth (implant-tooth sites) by analyzing determined distances. A total of 45 teeth and 46 implant-tooth sites were carefully selected. Clinical evaluation consisted of visual and quantitative analyses with millimeter grids on radiographs. Implant-tooth sites showed a smaller gingival papilla dimension than tooth sites (P < .01). Both evaluated distances (contact point to bone crest and between the roots of adjacent teeth or implant platform to root of adjacent tooth) in all groups significantly influenced the presence/absence of gingival papillae (P < .01).     

Functional and esthetic considerations for single-tooth Ankylos implant-crowns: 8 years of clinical performance

PROBLEM: Following the loss of an anterior natural tooth, the mucogingival complex begins to collapse. The early placement of endosseous dental implants can prevent or reduce the extent of this collapse. If there is a long interval between the loss of the natural tooth and the placement of the implant prosthetic replacement, this collapse tends to increase significantly. PURPOSE: This paper will report on the clinical success of this implant product in the fabrication of esthetic, functional, and harmonious replacements for missing single, natural teeth for a period of 8 years. METHOD: A total of 275 single Ankylos implant tooth restorations in the anterior and posterior jaw regions were placed and monitored for 8 years. Of these, 264 implants were restored using the titanium Balance abutments, and only 11 were restored using ceramic abutments. The final restorations were either metal-ceramic or full-ceramic crowns and were cemented with glass ionomer cement. RESULTS: The survival rate was 98.2%, with only 5 implants being lost during the healing phase. There were no other implant losses in the postloading period that averaged 3.2 years. To date, there have been no mechanical complications associated with the prosthetic components (ie, screw loosening, screw breaking, or crown breaking) for either the titanium or the ceramic abutments. CONCLUSIONS: Experience with the Ankylos system with single-tooth replacement indications may be considered positive with regard to the esthetic and functional results of the treatment. The lack of mechanical complications and problems with the hard and soft tissue in the loading phase of the implants suggests the functional safety of the tapered connection between implant and abutment.     

Single-tooth implants and their role in preserving remaining teeth: a 10-year survival study

The use of teeth as abutments for fixed and removable partial dentures can result in biologically destructive consequences. Teeth adjacent to edentulous spaces should exhibit improved prognoses if restorative trauma is to be avoided or minimized. Implants offer a method of tooth replacement without relying upon the surrounding dentition for support. This investigation evaluates implant survival and prosthetic complications of implants that replaced single missing teeth and were placed in clinical practice during a 10-year period. It further examines preoperative status and survival of teeth adjacent to these implant restorations during the same 10-year time span. Ninety-nine patients treated with 116 implants and 112 single-tooth implant prostheses in a prosthodontic practice were examined between 1988 and 1998. The purpose of this study was to evaluate the role of implants in preventing the use of intact teeth for initial support of prostheses and in avoiding the use of additional teeth as abutments upon the replacement of existing restorations. Three implants failed over a 10-year period, for a survival rate of 97.4%. Complications included the loss of 2 implant crowns, screw loosening, broken screws, cement washout, margin exposure, and porcelain fracture. Of 196 teeth adjacent to edentulous spaces, 156 (79.6%) were intact or minimally restored. Only 3 of these teeth were restored as part of initial prosthodontic therapy. Over the ensuing 10 years, only 1 tooth required a replacement restoration, and 1 tooth was extracted. Results of this patient evaluation demonstrated that implant survival over a 10-year period was favorable, with minimal prosthetic complications. Furthermore, teeth adjacent to single-tooth implants exhibited an extremely low complication rate. This report indicates that implants can be effective in preserving intact teeth in patients undergoing initial prosthodontic therapy and in preventing the use of additional teeth as abutments in patients whose existing prostheses must be replaced.     

Retrospective cross sectional comparison of initial nonsurgical endodontic treatment and single-tooth implants

Initial root canal treatment and the replacement of a single tooth with implants are both viable treatment options, but various success rates have been reported for each treatment modality. This study compared 196 implant restorations and 196 matched initial nonsurgical root canal treatment (NSRCT) teeth in patients for four possible outcomes- success, survival, survival with subsequent treatment intervention and failure. Cross classifications/tabulations were analyzed using Pearson's chi(2) test for association of the two classifications (endo vs. implant and outcome). Polytomous regression with likelihood ratio tests were used in testing association with tooth location and outcome. Outcomes were as follows for implants and NSRCT outcomes, respectively: success 73.5% and 82.1%; survival with no intervention 2.6% and 8.2%; survival with intervention 17.9% and 3.6%; and failure 6.1% and 6.1%. Location of the restoration in the mouth did not affect outcome. This study suggests that restored endodontically treated teeth and single-tooth implant restorations have similar failure rates, although the implant group showed a longer average and median time to function and a higher incidence of postoperative complications requiring subsequent treatment intervention.     

Comparative evaluation of the oral tactile function bv means of teeth or implant‐supported prostheses

To clarify more of the tactile function of oral implants, both an interocclusal thickness detection and discrimination task were carried out in 4 different test conditions on 37 patients: t (tooth)/t, i (implant)/t, i/i and d (denture)/o (overdenture supported by implants). For the interocclusal detection of steel foils, the 50% detection threshold level (RL) in the 4 conditions was 20, 48, 64 and 108 microns, respectively, which indicates significant differences. The ability to discriminate interdental thickness differences was tested with a 0.2 and 1.0 mm standard. It was evaluated as the 75% discrimination level (DL). In the 0.2 mm discrimination task, corresponding DL-values for the t/t, i/t, i/i and d/o condition were 25, 55, 66 and 134 microns, whereas the 1.0 mm standard gave values of 193, 293, 336 and 348 microns, respectively. All results differed significantly from each other (p less than 0.05) except for the i/i-d/o comparison of the 1.0 mm discrimination task where the difference was negligible. The present findings indicate that the tactile sensibility of implants is reduced with regard to natural teeth. Remaining receptors of the peri-implant tissues might play a compensatory role in the decreased exteroceptive function.     

Comparison of interproximal soft tissue height for single implants and contra-lateral natural teeth

Objective: To compare the interproximal soft tissue dimensions adjacent to single implant restorations in the premolar–molar position with those adjacent to the contra-lateral natural teeth.
Material and methods: Twenty-five patients with a single-tooth implant in premolar–molar position and healthy contra-lateral teeth were enrolled in this retrospective cross-sectional study. The reason for the extraction was periodontitis. Radiographs were used to measure the shortest distance from the tip of the papilla to the crestal bone in single implants and contra-lateral teeth. A Wilcoxon's signed-ranks test was used to examine the differences between the interproximal soft tissue dimensions adjacent to the single-tooth implant restorations (IS-STI) from those of the contra-lateral natural teeth (IS-NT).
Results: We found no significant difference between the mesial IS-STI and the mesial IS-NT (3.28±0.83/3.31±0.62; P =0.861), or between the distal IS-STI and the distal IS-NT (3.09±0.72/3.3±0.63; P =0.263).
Conclusions: The interproximal soft tissue height adjacent to single-implant-supported restorations in the premolar–molar position is similar to that adjacent to the contra-lateral natural teeth.     

A retrospective analysis of peri-implant tissue responses at immediate load/provisionalized microthreaded implants

PURPOSE: The aim of this retrospective study was to examine the peri-implant tissue status at immediately provisionalized anterior maxillary implants 12 to 30 months following tooth replacement. MATERIALS AND METHODS: This is a retrospective study of 43 microthreaded, TiO2 grit-blasted implants placed in healed ridges and immediate extraction sockets to restore maxillary anterior and premolar teeth in 28 patients. The cortical bone position relative to the implant reference point was evaluated at implant placement and 6 to 30 months following restoration. Radiographs were assessed using 7x magnification. The distance from the reference point to the cortical bone was measured to +/- 0.1 mm. The relationship of the peri-implant mucosa to the incisal edge of the definitive prosthesis was recorded. RESULTS: Four implants in 3 individuals failed during the first 6 weeks following placement and provisional loading. Cortical bone adaptation from the time of implant placement up to 30 months following restoration ranged from 0.0 mm to 1.5 mm (average, 0.33 +/- 0.40 mm mesially and 0.28 +/- 0.37 mm distally). The mean radiographic measurements from the interproximal crestal bone to the contact point were 4.53 +/- -0.91 mm (mesial) and 4.06 +/- 0.98. Maintenance and growth of papilla was observed in this group of immediate provisionalized single-tooth implants. Definitive abutment or abutment screw loosening was not observed. DISCUSSION: The linear clinical and radiographic measures of peri-implant tissue responses suggest that proper implant placement is followed by supracrestal biological width formation along the abutment and preservation of toothlike tissue contours. This may influence buccal peri-implant tissue dimensions. CONCLUSIONS: Generalized maintenance of crestal bone and the increased soft tissue dimension with maintenance of peri-implant papilla were identified as expected outcomes for immediate loading/provisionalization of microthreaded, TiO2 grit-blasted implants. Control of peri-implant tissues can be achieved to provide predictable and esthetic treatment for anterior tooth replacement using dental implants.     

The single-tooth implant: a viable alternative for single-tooth replacement

BACKGROUND: The use of dental implants for single-tooth replacement cases introduces a challenge to the performance of these restorations. Clinical data suggest that single-tooth implant restorations do not benefit from lateral support from the surrounding dentition as do bridged implants, and that these restorations are subjected to greater masticatory forces. Therefore, single-tooth implants are exposed to an increased risk of failure. This prospective clinical trial was designed to evaluate the cumulative success rate of dual acid-etched single-tooth replacement implants in two clinical centers. METHODS: The study protocol included 59 patients between 19 and 73 years. Implants were evaluated for mobility, infection, and crestal bone loss from 30.9 to 60 months. RESULTS: Seventy-one (71) implants were placed in 59 patients, 20 male and 39 female. Forty-seven (47) were placed in the maxilla and 24 in the mandible. The percentages of anterior and posterior implants were 45.1% and 54.9%, respectively. A total of 13 (18.4%) implants were placed in soft, poor quality (Type IV) bone. Beginning 1 month post-implant placement, cases were followed for 30.9 to 60 months with a mean follow-up of 45.9 months. One implant failed (peri-implant infection) yielding an overall success rate of 98.6%. CONCLUSIONS: This success rate for single-tooth replacement dual acid-etched implants compares favorably with bridged implants and with success rates of other single-tooth implant studies. Dual acid-etched implants performed well even under conditions of poor quality bone, where concomitant bone augmentation was performed, and when used for immediate replacement of extracted teeth.     

Factors associated with implant recommendation for single-tooth replacement

The use of dental implants for single-tooth replacement has been established as a predictable treatment option; yet, limited data are available as to how frequently this option is recommended to patients. The aim of the present study was to examine the frequency of implant recommendation by general dental practitioners after single-tooth extraction and factors influencing their decision to recommend an implant. All single-tooth extractions performed in 26 general dental practice clinics in Kuwait over a 30-day period were examined. Dentists in these centers used the study form to record demographic data, the type of tooth extracted, reason for extraction, and replacement options presented to the patients. Univariate and logistic regression analyses were used to examine associations between background factors and decisions to recommend implant therapy. A total of 1367 patients (mean age, 37.9 +/- 11.8 years) had an extraction of one tooth during the study period. Forty-three patients were offered implants as a replacement option (3.3% of the total sample; 8.6% of patients who were offered tooth replacement options). Factors associated significantly with the recommendation of an implant by Kuwaiti dentists to their patients included younger age, regular dental maintenance visits, and adequate oral hygiene practices (P < 0.05; binary logistic regression). Dental implant recommendation for single-tooth replacement in the present sample of dentists was low. Factors associated significantly with dentist recommendation of an implant for single-tooth replacement included age, history of dental maintenance, and oral hygiene practices.     

Status of teeth adjacent to single-tooth implants

PURPOSE: This study evaluated the status of teeth adjacent to single-tooth implants in the anterior and posterior jaw during a follow-up of more than 3 years. MATERIALS AND METHODS: Seventy-eight single-tooth implants and 148 adjacent teeth were followed for a mean of 58 months. Implant survival rate, peri-implant structures, and prosthetic complication rates were evaluated. Crowns and periodontal status of adjacent teeth were compared at crown placement and at the last examination. Horizontal distance from the implant edge to adjacent teeth was calculated and compared for anterior and posterior regions. The influence of approximal crestal bone resorption of the adjacent teeth was calculated using multivariate regression analysis. RESULTS: The clinical findings for implants (one loss), peri-implant structures, and prosthetic complication rates (three crown fractures) were excellent. There was a high proportion of intact adjacent teeth in both anterior and posterior regions at crown placement and at the follow-up examination. No adjacent teeth required extraction or endodontic treatment, and only four required restoration. Comparison of the periodontal status at crown placement and at follow-up revealed no differences for plaque and bleeding indices or for pocket depth of adjacent teeth. There was a significant influence of the horizontal distance on approximal bone loss in the closer distance of the anterior region, but not in the posterior region. CONCLUSION: The crown and periodontal status of teeth adjacent to single-implant restorations was excellent. The approximal bone crest reduction of the adjacent teeth was significantly influenced by the horizontal distance between the implant edge and neighboring tooth.     

A review of factors influencing treatment planning decisions of single-tooth implants versus preserving natural teeth with nonsurgical endodontic therapy

One of the major issues confronting the contemporary dental clinician is the treatment decision between extracting a tooth with placement of a dental implant or preserving the natural tooth by root canal treatment. The factors that dictate the correct selection of one procedure over the other for each particular case are not yet established by randomized controlled studies. The aim of this review is to evaluate key factors allowing the clinician to make clinical decisions on the basis of the best evidence and in the patient's best interests. General considerations are discussed that will help the reader analyze clinical studies focused on this problem. Importantly, the major studies published to date indicate that there is no difference in long-term prognosis between single-tooth implants and restored root canal-treated teeth. Therefore, the decision to treat a tooth endodontically or to place a single-tooth implant should be based on other criteria such as prosthetic restorability of the tooth, quality of bone, esthetic demands, cost-benefit ratio, systematic factors, potential for adverse effects, and patient preferences. It can be concluded that endodontic treatment of teeth represents a feasible, practical, and economical way to preserve function in a vast array of cases and that dental implants serve as a good alternative in selected indications in which prognosis is poor.     

Sensory responses from loading of implants: a pilot study

PURPOSE: Osseointegrated implants lack a periodontal ligament. Nevertheless, masticatory function in subjects with implant-supported restorations appears similar to function in those with natural dentition. It is not clear how the neurophysiologic mechanisms that modulate jaw movement are associated with osseointegrated implants. This study examined the output from the inferior alveolar nerve during implant loading. MATERIALS AND METHODS: In 3 dogs, 3 premolars were extracted in the mandible and 2 endosseous titanium implants were placed, allowed to osseointegrate for 3 months, and loaded with vibration force at the threshold response for tooth vibration, at 2x threshold, and at 3x threshold. Neurophysiologic recordings were made from the inferior alveolar nerve during loading of both implants and the adjacent molar and canine. The response magnitude in action potentials in the 50- ms poststimulus period and latency of inferior alveolar afferents in milliseconds were compared following implant loading. RESULTS: Detectable inferior alveolar nerve responses were recorded following loading from both the implants and the teeth at 2x and 3x threshold. However, the response magnitude of teeth (canine, 2.38 +/- 0.18 at 2x, 2.78 +/- 0.2 at 3x; molar, 2.2 +/- 0.16 at 2x, 2.5 +/- 0.21 at 3x) was twice that of the implants (anterior, 1.3 +/- 0.12 at 2x, 1.68 +/- 0.13 at 3x; posterior, 0.8 +/- 0.1 at 2x, 1.53 +/- 0.15 at 3x). The differences in response magnitude between the teeth and implants were significant (P < .05). The latency of response was similar. DISCUSSION: Management of the occlusion for implant-supported restorations has been empirically developed. An underlying assumption has been that implant-guided jaw function lacks significant proprioception to modulate mastication and related jaw movements. This animal study provides preliminary evidence that force application to implants does elicit a proprioceptive response. CONCLUSION: Loading of implants does elicit a sensory response that can be observed in the inferior alveolar nerve. The implications are that during occlusal function, information from regions associated with the implant can provide knowledge that could potentially modulate jaw activity in a manner similar to natural teeth.     

Tooth-implant and implant supported fixed partial dentures: a 10-year report

PURPOSE: The use of implants for prosthetic rehabilitation of partially edentulous patients is increasing. However, the possibilities of placing implants in the posterior part of the mandible are often limited. The purpose of this longitudinal study with 10 years of follow-up was to evaluate the use of short implants supporting fixed partial dentures (FPD) in the posterior part of the mandible, and to compare implant supported FPDs to tooth-implant supported FPDs. MATERIALS AND METHODS: The patient material comprised 23 patients with residual mandibular anterior teeth, and each patient received FPDs unilaterally. On one side the FPD was supported by two implants, and on the other side by one implant and one tooth, thus permitting intraindividual comparison. The distribution of the two types of FPDs in each jaw was randomized. Implant success rates, marginal bone changes, and mechanical complications were studied. RESULTS: The tooth-implant connection did not demonstrate any negative influences on the overall success rates for the 10-year period, nor were the shorter implants found to be less favorable. CONCLUSION: It is suggested that a prosthetic construction supported by both a tooth and an implant may be recommended as a predictable and reliable treatment alternative in the posterior mandible.     

Aesthetic outcome of single-tooth implant restorations following early implant placement and guided bone regeneration: crown and soft tissue dimensions compared with contralateral teeth

Objectives: The aim of this study was to compare crown and soft tissue dimensions of single-tooth implant restorations following early implant placement and guided bone regeneration (GBR) with contralateral non-restored teeth.
Material and methods: Twenty-seven patients treated by one and the same surgeon and prosthodontist to restore a single-tooth gap with a class I bone defect in the premaxilla by means of an implant-supported restoration were reviewed. Patients were examined at least 6 months following placement of the crown. All implants had been inserted 6–8 weeks following tooth extraction in conjunction with GBR. At evaluation, crown dimensions, soft tissue dimensions, clinical conditions and patients' aesthetic satisfaction were assessed by one clinician who had not been involved in the treatment.
Results: Implant-supported crowns were not significantly longer than contralateral teeth and midfacial soft tissues showed comparable levels after on average 21 months of function. Our data also indicated significant papilla loss especially at the distal aspect of the implants. As the patient's aesthetic appreciation was favourable in 88% of the cases, this appeared to be of trivial importance.
Conclusions: Favourable aesthetics may be achieved for single-tooth implant restorations following early implant placement and GBR. The impact of the latter on papilla levels, however, remains to be determined in longitudinal studies.     

Passive tactile sensibility in edentulous subjects treated with dental implants: a pilot study

STATEMENT OF PROBLEM: Edentulous patients treated with implant-supported prostheses have shown increased passive tactile sensibility compared with those using conventional complete dentures. This is thought to be due to the close mechanical coupling between the implant and bone via the osseointegrated interface, yet the phenomenon has received little attention. PURPOSE: The purpose of this study was to measure passive tactile sensibility in a group of edentulous subjects treated with dental implants, and to relate the measured sensibility to a range of factors thought to be of possible relevance, namely, patient age, gender, time since implant placement, implant length, and implant separation.MATERIAL AND METHODS: Twenty edentulous subjects successfully treated with 2 or more Nobel Biocare dental implants in the anterior mandible were studied. The inclusion criteria were : (1) age of less than 50 years, (2) a period of at least 12 months since implant placement, (3) implant length of at least 10 mm and of standard diameter (excluding narrow and wide platform designs), and (4) implant separation of at least 18 mm. Using a computer-controlled custom-made device, pushing forces (2.1, 2.4, 2.7, and 3.0 N/s) were applied directly and perpendicular to the long axes of the implant abutments until the subjects felt the first sensation of pressure. The magnitude of these forces was measured with an integral transducer. The applied force had a ramped staircase pattern, and force application rates were varied between 2.1 and 3.0 N/s. Multilevel modeling was used to analyze the collected data (alpha=.05). RESULTS: The threshold values of passive tactile sensibility ranged between 3.1 and 15.7 N (mean 10.9; SD 3.9). Analysis failed to show any significant association between passive tactile sensibility and the variables studied. CONCLUSION: Within the limitations of this study, which included a small sample size, no relationship was found between passive tactile sensibility associated with long-standing implants and any of the variables studied (age, gender, time since implant placement, implant length, and implant separation).     

Single-tooth replacement: bridge vs. implant-supported restoration

Options for restoring a single tooth include fixed partial denture, resin-bonded restoration and single-tooth implant. In this paper, we discuss the advantages and disadvantages of these methods and factors that must be considered when choosing between them for the replacement of a single tooth. Although in some cases a fixed partial denture is the most appropriate choice, implants have the advantage of allowing preservation of the integrity of sound teeth adjacent to the edentulous area.