Implant survival and patient satisfaction of reduced diameter implants made from a titanium-zirconium alloy: A retrospective cohort study with 550 implants in 311 patients

The aim of the study was to evaluate implant survival of reduced-diameter implants compared to regular-diameter implants. A retrospective evaluation of 154 Straumann Bone Level Roxolid^® implants (diameter 3.3 mm) with SLActive^®-surface in 107 patients, which were inserted between 2009 and 2010 in private practice, was performed. The mean observation period was 22.4 ± 8.2 months. 396 Straumann SLActive^® implants (4.1 mm and 4.8 mm) in 204 patients, with an observation period of 28.4 ± 10.1 months served as control group. Implant survival rate, resonance frequency analysis and patient satisfaction were evaluated. The implant survival rate was 97.4% in the test vs. 98.5% in the control group. Resonance frequency analysis showed statistically significant lower values for the reduced-diameter implants. Patient satisfaction showed no significant difference between the test and the control group. Reduced-diameter implants displayed high survival rates during the period investigated and represent a convincing treatment alternative. Long-term follow-up investigations confirmed the high implant survival rates of 96.8% (after 69.7 ± 12.3 months) in the test group and 98.5% (after 76.0 ± 13.6 months) in the control group.

Effectiveness of temporary implants in teenage patients: a prospective clinical trial

AIMS

The objective of this study was to assess prospectively the outcomes of extra-narrow diameter implants (XNDI) placed in teenage patients as a temporary restorative option.

MATERIAL AND METHODS

Twenty consecutive young patients presenting one or several missing teeth received XNDI that were immediately restored with composite, Polymethylmethacrylate (Acrylic) or ceramic crown. Clinical and radiographical outcomes were assessed for a minimum follow-up period of 1 year. Additionally, each patient completed retrospectively a satisfaction questionnaire using Visual Analog Scale (VAS).

RESULTS

A total of 30 implants were placed and followed for a period of 1-7.4 years (mean: 3.59 years). One implant failed after 3 weeks and was replaced successfully. No further biological complications occurred during the follow-up period, leading to an implant survival rate of 96.6%. The patient satisfaction evaluations displayed high levels of comfort and function.

CONCLUSION

Immediately restored XNDI to replace missing teeth on teenager patients seems to be an effective temporary restorative option to replace missing teeth in young patients. Composite or ceramic crowns should be preferred. Clinical trials with long-term follow-ups and the assessment of passive egression are needed.

Dental Implant Length and Diameter: A Proposed Classification Scheme

PURPOSE

To propose a length-and-diameter-based classification scheme for dental implants to standardize terminology in the dental literature and communication between interested parties.

MATERIALS AND METHODS

This study was mainly based on searching two major resources: published scientific research papers and 14 of the most popular dental implant manufacturers. Indexed databases were searched from January 2004 up to and including February 2016 using the keywords "dental implant length" and "dental implant diameter." Retrieved titles and abstracts were screened, and related full-text articles were reviewed. Full-text articles that clearly stated the terms and measurements of implants used were included and considered for proposing this classification scheme.

RESULTS

The initial search for implant diameter and length yielded 1007 and 936 articles, respectively. A total of 85 studies (41 about diameter, 44 about length) were selected and reviewed. The remaining studies (966 about diameter, 892 about length) that did not abide by the eligibility criteria were excluded. The terms "long," "short," "standard," "wide," and "narrow" were the most commonly used terms in the literature. A classification scheme for implants by diameter and length was proposed.

CONCLUSIONS

Indexed publications contain a variety of terms used by authors to describe diameter and length of dental implants without conformity and standardization. The classification scheme proposed in this article could serve as a reference for interested parties.

Rehabilitation of resorbed mandibular ridges using mini implant retained overdentures: A case series with 3 year follow-up

With the increasing average life expectancy of human beings, the need to cater geriatric patients is ever increasing. Complete dentures are an indispensable tool in this regard. The loose and unstable lower complete denture owing to residual ridge resorption is one of the most common problems faced by edentulous patients. Dental implant retained overdentures have emerged as an efficient treatment modality for such patients. Though useful, not every patient is a suitable candidate to go for conventional implant-borne prosthesis, limitation being the available bone width. In such cases, mini implants may be used for augmenting the retention of the dentures and improving the quality of life of patients. In this case series, rehabilitation of three compromised cases with mini implant retained overdentures have been described wherein patients are experiencing instability of lower denture due to thin resorbed mandibular ridges. In one of the cases, three mini implants placed in A, C, and E position were splinted using a cemented bar to retain the mandibular denture. The other two cases were rehabilitated using unsplinted ball type one piece mini implants placed in A, C, and E position in one case and B and D position in another case. Though splinted bar design should be preferred but the lack of available vertical space precluded the utilization of bar in other two cases. The results were found to be satisfactory with no complications reported during a follow-up period of over 3 years in all the cases.

Influence of rapid- and slow-rate resorption collagen membrane in maxillary sinus augmentation

OBJECTIVE

To evaluate the effects of low- and rapid-resorption-rate bioabsorbable collagen membranes in maxillary sinus augmentation procedure in rabbits considering Schneiderian membrane (SM) reaction and bone tissue formation.

MATERIALS AND METHODS

Eighteen male adult rabbits underwent bilateral maxillary sinus augmentation with particulate bovine hydroxyapatite to be divided into three groups, as follows: Group C - control, no membrane; Group RR - rapid resorbable collagen membrane; and Group SR - slow-resorbable collagen membrane. The animals were euthanized after 30 and 120 days for specimen's removal to be prepared and analyzed under light microscopy, histomorphometry, and immunohistochemistry for Runx2 and VEGF labeling.

RESULTS

Histopathology evaluation presented similar healing pattern among the groups with a satisfactory response of SM, both at day 30 and day 120. Bone histomorphometry did not reveal significant differences among the groups, as well as immunohistochemistry analysis, which presented intense immunolabeling for both proteins in all groups.

CONCLUSIONS

The presence of both membranes did not negatively interfere in bone formation and remodeling, and the focal mild inflammatory reaction caused by their degrading process did not impair the reconstructive procedure.

Immediate Implants Placed in Fresh Sockets Associated with Periapical Pathology: A Split-Mouth Design and Survival Evaluation after 1-Year Follow-Up

PURPOSE

To compare the immediate implant success rates between sites with chronic apical lesions and healthy sites in the same patients 1 year postdelayed loading.

MATERIALS AND METHODS

One hundred sixty-eight immediate implants were placed in sixty patients at upper incisor, canine, and premolar sites. A split-mouth design was used, placing a minimum of two implants, one in a fresh socket associated with chronic periapical disease, the average lesion size was larger than 4 mm and less than 8 mm (test group), and the other(s) in a healthy fresh socket (control group). Implant survival rate at 1 year postloading delayed was compared between the groups.

RESULTS

The implant survival rate was 98.2% for the total sample (n = 168); out of the three implants lost, two were from the test group, and one was from the control group (in the same patient as one of the former). Among the surviving implants, five were also considered failures due to excessive bone loss (n = 3) and also because of the recurrence of the periapical lesions (n = 2). Survival rates were significantly lower in the test than control sites at 12 months postloading.

CONCLUSIONS

Implant survival rates were significantly lower after the immediate implantation in postextraction sockets associated with chronic periapical disease (90.8%) than in healthy postextraction sockets (98.1%).

Small-diameter titanium grade IV and titanium-zirconium implants in edentulous mandibles: five-year results from a double-blind, randomized controlled trial

BACKGROUND

The aim of this study was to compare the 5-year survival and success rates of 3.3 mm dental implants either made from titanium-zirconium (TiZr) alloy or from Grade IV titanium (Ti Grade IV) in mandibular implant-based removable overdentures.

METHODS

The core study had a follow-up period of 36 months and was designed as a randomized, controlled, double-blind, split-mouth multicenter clinical trial. Patients with edentulous mandibles received two Straumann Bone Level implants (diameter 3.3 mm, SLActive®), one of TiZr (test) and one of Ti Grade IV (control), in the interforaminal region. This follow-up study recruited patients from the core study and evaluated the plaque and sulcus bleeding indices, radiographic crestal bone level, as well as implant survival and success 60 months after implant placement.

RESULTS

Of the 91 patients who initially received implants, 75 completed the 36 month follow-up and 49 were available for the 60 month examination. Two patients were excluded so that a total of 47 patients with an average age of 72 ± 8 years were analysed. The characteristics and 36-month performance of the present study cohort did not differ from the non-included initial participants (p > 0.05). In the period since the 36-month follow-up examination, no implant was lost. The cumulative implant survival rate was 98.9 % for the TiZr group and 97.8 % for the Ti Grade IV group. Crestal bone level changes at 60 months were not different in the test and control group (TiZr -0.60 ± 0.69 mm and Ti Grade IV -0.61 ± 0.83 mm; p = 0.96). The cumulative implant success rate after 60 months was 95.8 and 92.6 % for TiZr and Ti Grade IV, respectively.

CONCLUSIONS

After 60 months, the positive outcomes of the 36 month results for TiZr and Ti Grade IV implants were confirmed, with no significant differences with regard to crestal bone level change, clinical parameters and survival or success rates. TiZr implants performed equally well compared to conventional Ti Grade IV 3.3 mm diameter-reduced implants for mandibular removable overdentures.

TRIAL REGISTRATION

Registered on www.clinicaltrials.gov: NCT01878331.

Mini vs. Standard Implants for Mandibular Overdentures

A mandibular implant-retained overdenture is considered a first-choice treatment for edentulism. However, some aspects limit the use of standard implants—for example, the width of edentulous ridges, chronic diseases, fear, or costs. This randomized trial compared mandibular overdentures retained by 2 or 4 mini-implants with standard implants, considering oral health–related quality of life (OHRQoL), patient satisfaction, and complications such as lost implant. In sum, 120 edentulous men and women (mean age, 59.5 ± 8.5 y) randomly received 4 mini-implants, 2 mini-implants, or 2 standard implants. Participants provided data regarding OHRQoL and satisfaction until 12 mo. Clinical parameters, including implant survival rate, were also recorded. Both 2 and 4 mini-implants led to better OHRQoL, compared with 2 standard implants. Treatment with 4 mini-implants was more satisfying than 2 standard implants, with 2 mini-implants presenting intermediate results. Implant survival rate was 89%, 82%, and 99% for 4 mini-implants, 2 mini-implants, or 2 standard implants, respectively. Overdentures retained by 4 or 2 mini-implants can achieve OHRQoL and satisfaction at least comparable with that of 2 standard implants. However, the survival rate of mini implants is not as high as that of standard implants ( ClinicalTrials.gov NCT01411683).

Narrow- versus mini-implants at crestal and subcrestal bone levels. Experimental study in beagle dogs at three months

OBJECTIVE

The objective of this study was to evaluate the osseointegration and crestal bone loss (CBL) in two implant designs with different diameters (Mini Sky® and Narrow Sky®) implants, placed at different vertical levels at healed canine ridges.

MATERIAL AND METHODS

The second, third, and fourth mandibular premolars of six Beagle dogs were extracted bilaterally. After 2 months healing, four implants divided into two groups according to their diameters (i.e., Narrow Sky® and Mini Sky®) were placed in each hemi-mandible at the level of the bone crest or 2 mm subcrestally. The animals were euthanized at 12 weeks and undecalcified samples were processed for histology. Histomorphometric analysis was carried out to compare bone-to-implant contacts (BIC) and crestal bone loss (CBL).

RESULTS

There were not significant differences in CBL between groups when the implants were placed at subcrestal bone level (p > 0.05), meanwhile the CBL was significantly higher for both groups when the implants were inserted at crestal level (p < 0.05). All implants were osseointegrated presenting a minimum BIC percentage of 56%. The major percentages of BIC were found for both groups at subcrestal level (p < 0.05).

CONCLUSIONS

Within the limitations of this experimental study may be concluded that the implant diameter does not affect the CBL. BIC values are affected by implant diameter and design been higher for narrow implants compared to mini-implants. Subcrestal insertion of both implants favors crestal bone preservation but crestal insertion of both designs is associated with crestal bone loss

CLINICAL RELEVANCE

The study shows that narrow implants protect peri-implant crestal bone.

Temporary replacement of missing maxillary lateral incisors with orthodontic miniscrew implants in growing patients: rationale, clinical technique, and long-term results

The missing maxillary lateral incisor in adolescent patients presents an orthodontic challenge. Historically, there have been three treatment options to address this clinical problem: (1) canine substitution, (2) tooth auto-transplantation, and (3) dental restoration. Unfortunately, these methods are not without limitation. A novel treatment concept, originating in 2003 and utilizing orthodontic miniscrew implants, is presented along with the rationale, clinical technique and 8 years of follow-up.

Immediate restoration of fixed partial prostheses supported by one-piece narrow-diameter selective laser sintering implants: a 2-year prospective study in the posterior jaws of 16 patients

PURPOSE

Selective laser sintering (SLS) is a new technique that allows implants to be produced by annealing titanium powder microparticles in a focused laser beam, according to a computer-generated model. The aim of this study was to evaluate the survival and success rate of immediately restored 1-piece narrow-diameter SLS implants, placed in the posterior jaws, after 2 years of functional loading.

MATERIALS AND METHODS

At the 2-year follow-up examination, several parameters were assessed. Success criteria included absence of pain, suppuration, exudation, implant mobility; distance between the implant shoulder and the first visible bone-to-implant contact <2.0 mm; and absence of prosthetic complications.

RESULTS

Thirty-seven implants were placed in the posterior jaws (14 maxilla, 23 mandible) of 16 patients (9 males, 7 females). The prosthetic restorations comprised 16 immediately restored fixed partial prostheses. No implant failure occurred, resulting in a 100% survival rate. The implant success was 94.6%, and the mean distance between the implant shoulder and the first visible bone-to-implant contact (DIB) was 0.4 ± 0.3 mm.

CONCLUSIONS

This study supports the hypothesis that 1-piece narrow-diameter SLS implants can be used in fixed prosthetic rehabilitations in the posterior regions of both jaws with a predictable positive outcome.

Implant diameter and length influence on survival: interim results during the first 2 years of function of implants by a single manufacturer

OBJECTIVES

The aim of the present study was to evaluate the influence of implant length and diameter on implant survival.

METHODS

A retrospective cohort of 787 consecutive patients from 2 private practices between the years 2008 and 2011 had been evaluated. Patient demographics, site and implant characteristics, and time of follow-up were recorded from the medical files.

RESULTS

Overall, 3043 implants were investigated. Overall survival rate was 98.7% with 39 implant failures recorded. Survival rates for narrow- (<3.75 mm), regular- (3.75-5 mm), and wide- (>5 mm) diameter implants were 98.2%, 98.7%, and 98.5%, respectively (P = 0.89). Survival rates of short (<10 mm) and regular (10 mm and above) implants were 97% and 98.7%, respectively (P = 0.22).

CONCLUSIONS

Implant length and diameter were not found to be significant factors affecting implant survival during the first 2 years of function in the present investigation of this specific implant system by a single manufacturer. Further long-term follow-up studies are warranted because 2-years are only interim short-term results when dealing with dental implants.

Less Invasive Surgical Procedures Using Narrow-Diameter Implants: A Prospective Study in 20 Consecutive Patients

Narrow-diameter implants (NDIs) are increasingly produced and used in implant dentistry, especially since the introduction of new, more resistant materials. The objective of the present study was to evaluate the clinical performance of NDIs (3.3 mm) placed in thin alveolar crests. Twenty consecutive patients needing implant-supported fixed partial dentures and presenting an alveolar thickness ≤6 mm were treated with 1 or several NDIs. The surgical protocol was chosen according to the clinical situation: (1) flapless, (2) mini-cervical flap, (3) wide flap, (4) wide flap + guided bone regeneration (GBR). Implants were immediately loaded if the primary stability was higher than 20 Ncm. Implant survival and success, prosthodontic success rates, and patient-centered outcomes were evaluated after a follow-up period of 1 year. A total of 39 implants were placed in 20 patients, 12 and 27 implants in the anterior regions and in the posterior mandible, respectively. All but 1 implant reached an insertion torque higher than 20 Ncm and were loaded within 48 hours. The implant survival and success rates both reached 94.7%. The need for GBR was avoided in 60% of the implant sites. The mean peri-implant bone remodeling after a follow-up period of 1 year was -0.35 mm at the implant level. Peri-implant bone remodeling was higher in the posterior region, when the alveolar crest was thinner than 4 mm and GBR was required in addition. In conclusion, use of NDIs to restore partial edentation in sites with limited horizontal thickness seems to be an effective treatment option that prevented GBR in the majority of the present cases. Immediate provisionalization of NDIs does not seem to impair the results.

Lateral forces exerted through ball or bar attachments in relation to the inclination of mini-implant underneath overdentures: in vitro study

OBJECTIVE

Lateral force to mini-implants should be avoided because mini-implants are weak mechanically because of its small diameter. Overdentures retained by mini-implants are usually formed using ball attachments. However, bar attachments can offer the advantage of splinting the mini-implants. This study examined the effect of attachments in withstanding these lateral forces in tilted mini-implants of overdentures.

MATERIALS AND METHODS

Strain gauges were attached to the mini-implants (2.5 × 18 mm) embedded in an acrylic resin block. Two mini-implants were inserted vertically (Control) or with one mini-implant inclined at 10° or 20° (10-inclined and 20-inclined, respectively). The female portions of the attachments were secured to the denture base. A prefabricated ball attachment and CAD/CAM-fabricated bar attachment were compared. A vertical load of 49 N was applied to the occlusal surface at a distance 10 mm away from the center of two mini-implants. The lateral force borne by the mini-implants was measured via the attached strain gauge. Mann-Whitney U-test and an analysis of Bonferroni correction were used to compare differences between the two attachments and among the three models (P < 0.05).

RESULTS

The lateral force exerted to the inclined mini-implant was significantly greater than that borne by a vertical mini-implant for both attachment types. The lateral force on the 20° inclined mini-implants with bar attachments was smaller than that on mini-implants with ball attachments.

CONCLUSION

Inclined mini-implants are subjected to greater stresses than vertical ones, and a bar attachment can reduce the lateral forces borne by the mini-implant when one mini-implant inclined at 20°.

Small-diameter titanium Grade IV and titanium-zirconium implants in edentulous mandibles: three-year results from a double-blind, randomized controlled trial

OBJECTIVE

The aim of this study was to compare crestal bone-level changes, soft tissue parameters and implant success and survival between small-diameter implants made of titanium/zirconium (TiZr) alloy or of Grade IV titanium (Ti) in edentulous mandibles restored with removable overdentures.

MATERIALS AND METHODS

This was a randomized, controlled, double-blind, split-mouth multicenter clinical trial. Patients with edentulous mandibles received two Straumann bone-level implants (diameter 3.3 mm), one of Ti Grade IV (control) and one of TiZr (test), in the interforaminal region. Implants were loaded after 6-8 weeks and removable Locator-retained overdentures were placed within 2 weeks of loading. Modified plaque and sulcus bleeding indices, radiographic bone level, and implant survival and success were evaluated up to 36 months.

RESULTS

Of 91 treated patients, 75 completed the three-year follow-up. Three implants were lost (two control and one test implant). The survival rates were 98.7% and 97.3%, and the mean marginal bone level change was -0.78 ± 0.75 and -0.60 ± 0.71 mm for TiZr and Ti Grade IV implants. Most patients had a plaque score of 0 or 1 (54% for test and 51.7% for control), and a sulcus bleeding score of 0 (46.1% for test and 44.9% for control). No significant differences were found between the two implant types for bone-level change, soft tissue parameters, survival and success.

CONCLUSIONS

After 36 months, similar outcomes were found between Ti Grade IV and TiZr implants. The results confirm that the results seen at 12 months continue over time.

Osseointegration of short titan implants: A pilot study in pigs

Reduced vertical bone level in the implantation area is often considered one of the limiting factors before implant insertion. Inserting implants of reduced length might be useful in order to avoid vertical bone augmentation prior to implantation. To the present day, no official guidelines exist as to the optimal length for these implants. It is nevertheless well known that the stability of an implant depends primarily on its osseointegration, which could otherwise be influenced by modifying implant surface texture. The aim of our study was to evaluate osseointegration in correlation with implant length and surface texture. Three different variations of titan implants (n=5) were compared: two types, each with an acid-etched and ceramic blasted surface, were inserted in the upper jaw of adult female minipigs at different lengths (tioLogic ST Shorty, 5mm length; tioLogic ST, 9mm length) and were compared to a control group (tioLogic ST, 9mm length, ceramic blasted surface). Eight weeks after unloaded healing, bone tissue specimens containing the implants were processed, stained with Masson-Goldner-trichrome and analyzed histologically. Regardless of implant length and surface texture, new bone formation with no signs of inflammation could be detected in the area of the threads. Implants with a modified surface showed no statistically significant difference in bone-implant-contact (BIC) (tioLogic ST Shorty, 56.5%; tioLogic(©)ST; 77.2%), but a statistically significant difference could be found, when the 9mm implants were compared to the control group (BIC 48.9%). Surface modification could positively influence osseointegration as well as contribute to overcoming the adverse effects of length reduction.

A Prospective Noninterventional Study to Evaluate Survival and Success of Reduced Diameter Implants Made From Titanium-Zirconium Alloy

Narrow diameter implants may be at increased risk of overload due to occlusal forces; therefore, implants with higher fatigue strength may be beneficial. The aim of this observational study was to evaluate survival and success of narrow diameter (Ø 3.3 mm) TiZr alloy (Roxolid, Institut Straumann AG, Basel, Switzerland) implants for 2 years in daily dental practice. This was a prospective, non-interventional, multicenter study; no specific patient inclusion or exclusion criteria were applied. Each patient received at least one TiZr implant; the treatment plan, including implant loading and final restoration, was at the investigator's discretion. The primary outcome was implant survival and success after 1 year. Secondary outcomes included 2-year survival and success and marginal bone level change. A total of 603 implants were placed in 357 patients. Cumulative survival and success rates were 97.8% and 97.6%, respectively, after 1 year and 97.6% and 97.4%, respectively, after 2 years. Bone levels remained stable in the majority of patients, and soft tissue remained stable up to 2 years. Within the limitations of a non-interventional study design, TiZr implants showed excellent survival and success with minimal bone loss up to 2 years in daily dental practice. The results compare favorably with those of small-diameter implants in controlled clinical trials.

Narrow-diameter implants: are they a predictable treatment option? A literature review

OBJECTIVE

To evaluate the predictability of narrow-diameter implants as a treatment option in routine clinical practice. A literature review was performed of studies reporting clinical results obtained with these implants. Survival rates, peri-implant bone loss and related complications were evaluated. The working hypothesis was that narrow-diameter implants offer clinical results similar to those obtained with implants of greater diameter.

MATERIAL AND METHODS

A Medline-PubMed search covering the period between 2002 and 2012 was carried out. Studies published in English and with a follow-up period of at least 12 months were considered for inclusion. A manual search was also conducted in different journals with an important impact factor. results: Twenty-one studies meeting the screening criteria were included in the literature review. A total of 2980 narrow-diameter implants placed in 1607 patients were analyzed.

CONCLUSIONS

The results obtained from the literature indicate that narrow-diameter implants are a predictable treatment option, since they afford clinical results comparable to those obtained with implants of greater diameter.

Geriatric slim implants for complete denture wearers: clinical aspects and perspectives

Background

Advances made in prevention have helped postpone complete edentulism in older patients. However, in the elderly, the physiological state reduces patients’ ability to adapt to oral rehabilitation and degrades the patient’s oral condition. Consequently, elderly edentulous subjects avoid many types of foods, which can lead to substantial nutritional consequences. Complete dentures retained by implants are, currently, the treatment of reference in prosthodontic mandibular rehabilitation. Indeed, the mandibular symphysis generally tolerates implantation, even when the mandible is strongly resorbed. However, in the elderly, implant rehabilitation is compromised by the complexity of the surgical protocol and possible postoperative complications. In this context, the use of geriatric “slim implants” (GSI) offers an interesting alternative.

Methods

In the present study, the surgical and prosthetic procedures for the use of GSI in a French dental hospital are presented. The objective was the stabilization of a complete mandibular denture in an elderly person, with the immediate implantation of four GSI.

Results

The operating procedure was found to be less invasive, less expensive, simpler, and more efficient than the conventional procedure.

Conclusion

The result strongly suggests that this protocol could be used systematically to treat complete edentulism in very elderly patients. Long-term monitoring and the evaluation of the reliability of this type of rehabilitation should be undertaken.

The influence of implant diameter on its survival: a meta-analysis based on prospective clinical trials

BACKGROUND

The use of narrow-diameter implants has been proposed to restore small edentulous spans, thus avoiding extensive bone augmentation procedures and reducing the surgical complexity of implant rehabilitations. Although success rates of narrow-diameter implants have already been analyzed in the literature, to the best of the authors' knowledge, no meta-analysis based on prospective and randomized controlled trials has been performed. The aim of this study is to analyze the survival rates of narrow-diameter implants compared with standard or wide-diameter implants.

METHODS

An electronic search from three databases and a hand search in implant-related journals of studies published in English before September 1, 2012 were performed. Prospective human clinical studies with at least 10 implants and a follow-up period of 1 year were included in the meta-analysis. Implants were divided into two groups based on their diameters.

RESULTS

The initial search yielded 484 articles, of which 49 were evaluated in full text for eligibility. Finally, 16 studies were chosen and separated into two groups: 1) implants of diameter <3.3 mm (group 1) and 2) implants of diameter ≥3.3 mm (group 2). A meta-analysis performed for groups 1 and 2 showed survival rates of 75% and 87%, respectively.

CONCLUSIONS

This meta-analysis showed that narrower implants (<3.3 mm) had significantly lower survival rates compared with wider implants (≥3.3 mm). Other variables, such as type of prosthesis, implant surface, and timing of prosthetic loading, were found to have influenced the implant survival rates.

Patient satisfaction with mini-implant stabilised full dentures. A 1-year prospective study

The purpose of this study was to evaluate patient-centred outcomes with regard to function and comfort after placement of mini-implants for stabilisation of complete dentures. The trial was designed as a prospective cohort of 12-months duration and involved 21 subjects in the age of 50-90 years having a full denture in the maxilla or the mandible with poor stability during function. Flapless installation of 2-4 narrow-body Dentatus Atlas(®) implants was performed and retention for the existing denture was obtained by the use of a silicone-based soft lining material (Tuf-Link(®)). Patients' judgement of perceived satisfaction with function and comfort of the dentures was recorded at baseline, 1- and 12-months post-treatment using 10-centimetre visual analogue scales (VAS) and a questionnaire. Clinical examination of the conditions of the peri-implant soft tissues was performed at 12 months. Nineteen of the 21 patients were available for the 12-month follow-up examination. The two drop-out subjects lost all implants within 1 month and rejected retreatment. Further six subjects lost 1-2 implants, but were sucessfully retreated by insertion of new implants. Overall satisfaction, chewing and speaking comfort were all markedly improved from pre-treatment median VAS scores of around 4-5 to median scores of 9·0-10 (10 = optimal) at the final examination. The prevalence of positive answers to questions regarding stability/function of the denture increased significantly to almost 100% for all questions. Treatment involving maxillary dentures and the use of short implants (7-10 mm) was associated with an increased risk of implant failure. The results indicate that placement of mini-implants as retentive elements for full dentures with poor functional stability has a marked positive impact on the patients' perception of oral function and comfort as well as security in social life.

Effect of dental implant diameter on fatigue performance. Part I: mechanical behavior

AIM

The purpose of this study was to evaluate the effect of the implants' diameter on the mechanical function and load-fatigue performance of dental implants.

MATERIALS AND METHODS

Three groups of implants with different diameters (3.3 mm, 3.75 mm and 5 mm), were tested under static and cyclic compressive loading. A total number of 15 implants for the static test and 112 implants for the cyclic-fatigue test. In the cyclic test, the machine ceased operating when the structure collapsed or when it reached 5 × 10(6) cycles without apparent failure. The load versus the number of cycles was plotted as curves for biomechanical analysis (S-N curve) for each implant diameter.

RESULTS

The S-N curve plotted for the 5 mm implants showed classic fatigue behavior with a finite life region starting from 620N. The same was observed for the 3.75 mm diameter implants, with a finite life region starting below 620N. By contrast, the 3.3 mm diameter implants failed to show predictable fatigue behavior and a fatigue limit could not be defined.

CONCLUSIONS

The results of this study emphasize the importance of implant diameter on fatigue behavior. Narrow implants failed to show typical fatigue behavior which might be attributed to the implant design.