Rehabilitation of irradiated patients with modified and conventional sandblasted acid-etched implants: preliminary results of a split-mouth study

Purpose: The aim of this study was to evaluate the success rate of chemically modified and conventional sandblasted acid‐etched surface (SLA) titanium implants in irradiated oral squamous cell carcinoma patients. Material and methods: Twenty patients with a mean age of 61.1 years were treated with dental implants after ablative surgery and radio‐chemotherapy of oral cancer. All patients were non‐smokers. The placement of SLA and modSLA implants was performed bilaterally according to a split‐mouth design. All 102 implants (50 SLA, 52 modSLA) placed showed an unloaded healing time of 6 weeks in the mandible and 10 weeks in the maxilla. Mean crestal bone changes using standardized orthopantomographies and clinical parameters like pocket depths, mPII and mBI were evaluated. Results: Of 102 implants, 55 implants (27 SLA implants, 28 modSLA) were located in the maxilla and 47 implants (23 SLA, 24 modSLA) in the mandible. The average observation period was 14.4 months. The amount of bone loss at the implant shoulder of SLA implants was 0.4 mm mesial and 0.4 mm distal. The modSLA implants displayed a bone loss of mesial 0.3 mm and distal 0.3 mm. Two SLA implants were lost resulting in a success rate of 96%. The success rate of modSLA implants was 100%. Conclusion: Regarding the data found in this investigation, we can conclude that implants with chemically modified and conventional SLA titanium surface show high success rates in irradiated patients. SLA implants with or without a chemically modified surface regardless of the location can be restored with a high predictability of success at least in the short time range observed. To cite this article:
Heberer S, Kilic S, Hossamo J, Raguse J‐D, Nelson K. Rehabilitation of irradiated patients with modified and conventional sandblasted, acid‐etched implants: preliminary results of a split‐mouth study.
Clin. Oral Impl. Res. 22 , 2011; 546–551
doi: 10.1111/j.1600‐0501.2010.02050.x     

Immediate loading short implants inserted on low bone quantity for the rehabilitation of the edentulous maxilla using an All‐on‐4 design

More studies evaluating the outcome of short‐length dental implants in immediate loading are needed. To evaluate the use of short‐length tapered implants in immediate loading for complete edentulous maxillae rehabilitations using an All‐on‐4 design. This retrospective clinical study included a cohort of 43 patients with 172 implants (74 short‐length implants) inserted in low bone quantity. The patients were followed between 4 months and 6 years (average = 3 years). Outcome measures were implant survival, marginal bone remodelling, biological and mechanical complications. Two patients with four short‐length implants were lost to follow‐up during the first year. Three short and three long implants failed in four patients, rendering an overall cumulative survival rate implant and patient level, respectively, of 95·7% and 95·1% for short implants, 100% for regular implants and 96·6% and 95·2% for long implants. The average marginal bone remodelling at 1 and 3 years was 0·97 and 1·25 mm for the short implants, 0·82 and 0·87 mm for regular implants and 0·87 and 0·98 mm for long implants. Three patients presented 4 short‐length implants with peri‐implant pockets (3 implants in 2 patients were pseudo‐pockets). Mechanical complications were registered in 13 patients (7 provisional prostheses fractures and 6 abutment screw loosening). All complications were treated successfully. Within the limitations of this clinical study, the short‐term outcome of fixed prosthetic complete edentulous maxillae rehabilitations supported by short‐length implants inserted in low bone quantity areas is viable. Long‐term clinical studies are necessary for evaluating the outcome of these implants.     

Histological evaluation of the peri‐implant tissues of three human‐retrieved Straumann implants

The most frequently‐used histological parameters to define dental implant osseointegration include bone‐to‐implant contact and quantitative and qualitative assessments of the surrounding tissue (rate of mineralized/non‐mineralized tissue and proportion of lamellar and woven bone compared to soft tissue or bone marrow). The aim of this paper was to present the histological features of the bone tissue surrounding three well‐functioning Straumann SLA and SLActive implants placed in two patients after 12 and 60 months of loading. The percentage of osseointegration ranged from 66.4% and 71.9% for SLA surfaces, to 88.3% for the SLActive implant. Such results confirm that osseointegration occurs with high rates of bone‐to‐implant contact in humans, and that implants can be similarly clinically successful, although they show different bone‐to‐implant contact values.     

Prospective 10‐Year Cohort Study Based on a Randomized Controlled Trial (RCT) on Implant‐Supported Full‐Arch Maxillary Prostheses. Part 1: Sandblasted and Acid‐Etched Implants and Mucosal Tissue

Background: There have been very few long‐term controlled studies (i.e., over 5 years duration) focusing on marginal conditions for implants with a sandblasted, large grit, and acid‐etched (SLA) surface. Purpose: To evaluate and report 10‐year data on outcomes of implants with an SLA surface placed in the edentulous maxilla. Materials and Methods: In a randomized controlled trial (RCT) cohort of 24 patients, the outcomes of implants with an SLA surface were registered. The RCT cohort has previously been reported after 1 year, 3 years, and 5 years of loading. Results: One patient dropped out of the study prior to the 10‐year control. Of the 23 remaining patients, the implant survival rate was 95.1%. If implants of unknown status were also considered lost, that is, one drop‐out patient with three implants for whom no information could be obtained, the implant survival rate was 93%. The mean marginal bone loss from baseline (139 implants) to 10 years (102 implants) was 1.07 mm (standard deviation 0.98). One implant out of 102 available for radiographic examination according to the original protocol showed a bone loss exceeding 4 mm. Of the 84 implants available for clinical examination, none showed a Plaque Index or sulcus bleeding index of 3. The mean implant stability quotient was significantly higher for mesial–distal versus buccal–palatal measurements. Conclusion: The implant survival was 95.1%. The mean value of bone loss after 10 years was 1.07 mm. Peri‐implantitis were noted at the 5‐year follow‐up for one patient with a previous history of periodontitis; this patient did not attend the 10‐year follow‐up. This study shows that sandblasted and acid‐etched implants offers predictable long‐term results as support for full‐arch maxillary prostheses.     

10‐Year Survival and Success Rates of 511 Titanium Implants with a Sandblasted and Acid‐Etched Surface: A Retrospective Study in 303 Partially Edentulous Patients

Purpose: This retrospective study assessed the 10‐year outcomes of titanium implants with a sandblasted and acid‐etched (SLA) surface in a large cohort of partially edentulous patients. Materials and Methods: Records of patients treated with SLA implants between May 1997 and January 2001 were screened. Eligible patients were contacted and invited to undergo a clinical and radiologic examination. Each implant was classified according to strict success criteria. Results: Three hundred three patients with 511 SLA implants were available for the examination. The mean age of the patients at implant surgery was 48 years. Over the 10‐year period, no implant fracture was noted, whereas six implants (1.2%) were lost. Two implants (0.4%) showed signs of suppuration at the 10‐year examination, whereas seven implants had a history of peri‐implantitis (1.4%) during the 10‐year period, but presented with healthy peri‐implant soft tissues at examination. The remaining 496 implants fulfilled the success criteria. The mean Plaque Index was 0.65 (±0.64), the mean Sulcus Bleeding Index 1.32 (±0.57), the mean Probing Depth 3.27 mm (±1.06), and the mean distance from the implant shoulder to the mucosal margin value ?0.42 mm (±1.27). The radiologic mean distance from the implant shoulder to the first bone‐to‐implant contact was 3.32 mm (±0.73). Conclusion: The present retrospective analysis resulted in a 10‐year implant survival rate of 98.8% and a success rate of 97.0%. In addition, the prevalence of peri‐implantitis in this large cohort of orally healthy patients was low with 1.8% during the 10‐year period.     

Carbon fibre versus metal framework in full‐arch immediate loading rehabilitations of the maxilla – a cohort clinical study

Frameworks made of carbon fibre‐reinforced composites (CFRC) seem to be a viable alternative to traditional metal frameworks in implant prosthodontics. CFRC provide stiffness, rigidity and optimal biocompatibility. The aim of the present prospective study was to compare carbon fibre frameworks versus metal frameworks used to rigidly splint implants in full‐arch immediate loading rehabilitations. Forty‐two patients (test group) were rehabilitated with full‐arch immediate loading rehabilitations of the upper jaw (total: 170 implants) following the Columbus Bridge Protocol with four to six implants with distal tilted implants. All patients were treated with resin screw‐retained full‐arch prostheses endowed with carbon fibre frameworks. The mean follow‐up was 22 months (range: 18–24). Differences in the absolute change of bone resorption over time between the two implant sides (mesial and distal) were assessed performing a Mann–Whitney U‐test. The outcomes were statistically compared with those of patients rehabilitated following the same protocol but using metal frameworks (control group: 34 patients with 163 implants – data reported in Tealdo, Menini, Bevilacqua, Pera, Pesce, Signori, Pera, Int J Prosthodont, 27, 2014, 207). Ten implants failed in the control group (6·1%); none failed in the test group (P = 0·002). A statistically significant difference in the absolute change of bone resorption around the implants was found between the two groups (P = 0·004), with greater mean peri‐implant bone resorption in the control group (1 mm) compared to the test group (0·8 mm). Carbon fibre frameworks may be considered as a viable alternative to the metal ones and showed less marginal bone loss around implants and a greater implant survival rate during the observation period.     

Early osseointegration to hydrophilic and hydrophobic implant surfaces in humans

Objective: To evaluate the rate and degree of osseointegration at chemically modified moderately rough, hydrophilic (SLActive) and moderately rough, hydrophobic (SLA) implant surfaces during early phases of healing in a human model. Material and methods: The devices used for this study of early healing were 4 mm long and 2.8 mm in diameter and had either an SLActive chemically modified or a moderately rough SLA surface configuration. These devices were surgically installed into the retro‐molar area of 49 human volunteers and retrieved after 7, 14, 28 and 42 days of submerged healing. A 5.2‐mm‐long specially designed trephine with a 4.9 mm inside diameter, allowing the circumferential sampling of 1 mm tissue together with the device was applied. Histologic ground sections were prepared and histometric analyses of the tissue components (i.e. old bone, new bone, bone debris and soft tissue) in contact with the device surfaces were performed. Results: All device sites healed uneventfully. All device surfaces were partially coated with bone debris. A significant fraction of this bone matrix coating became increasingly covered with newly formed bone. The process of new bone formation started already during the first week in the trabecular regions and increased gradually up to 42 days. The percentage of direct contact between newly formed bone and the device (bone‐to‐implant contact) after 2 and 4 weeks was more pronounced adjacent to the SLActive than to the SLA surface (14.8% vs. 12.2% and 48.3% vs. 32.4%, respectively), but after 42 days, these differences were no longer evident (61.6% vs. 61.5%). Conclusion: While healing showed similar characteristics with bone resorptive and appositional events for both SLActive and SLA surfaces between 7 and 42 days, the degree of osseointegration after 2 and 4 weeks was superior for the SLActive compared with the SLA surface. To cite this article :
Lang NP, Salvi GE, Huynh‐Ba G, Ivanovski S, Donos N, Bosshardt DD. Early osseointegration to hydrophilic and hydrophobic implant surfaces in humans.
Clin. Oral Impl. Res. 22 , 2011; 349–356. doi: 10.1111/j.1600‐0501.2011.02172.x     

An analysis of the implant‐supported overdenture in the edentulous mandible

This investigation examined the cumu‐lative survival rate of the implant‐supported overdenture using two types of attachments in patients treated at Show Chwan Memorial Hospital Implant Center from 1992 to 2006. Fifty‐one patients (30 men and 21 women) were treated with mandibular implant‐supported overdentures. Attachment systems used were the Hader bar with bilateral, cast ERA attachments (Group A, 31 patients with 15 men and 16 women, 134 implants) and the Hader bar with bilateral, distal extension cantilevers (Group B, 20 patients with 15 men and 5 women, 85 implants). Two hundred and four implants remained at the end of the follow‐up period. Among failed implants, 10 implants were in Group A (failure rate: 10/134 = 7·5%), whereas five implants were in Group B (failure rate: 5/85 = 5·9%). Sixty‐six point seven per cent (10/15) of failed implants were placed in the distal anterior mandible, and 33·3% (5/15) were placed in the middle anterior mandible. Survival was also examined with respect to condition of the opposing arch. Patients wearing a maxillary removable partial denture had the highest implant failure rate (5/51 = 9·8%), whereas the failure rate of the maxillary complete denture group was only 5·7%. The most frequent need for maintenance was wear over patrix component of ERA or Hader clip (n = 56). Eight patients experienced connector fracture between ERA and Hader bar, and one experienced distal extension cantilever fracture. The implant‐supported overdenture can be an effective and reliable alternative to the conventional complete mandibular denture. Fewer prosthetic complications were seen in overdentures retained with distal extension cantilever attachments.     

A 10‐Year Prospective Study of Single Tooth Implants Placed in the Anterior Maxilla

Purpose: The aim of the study was to evaluate the biological and technical outcomes of early and delayed placed single tooth implants after 10 years of follow‐up. Materials and Methods: Twenty consecutive patients who needed a single tooth replacement in the anterior maxilla were included in this study. Ten implants were placed with an early placement protocol, that is, 4 weeks after tooth extraction, whereas the other 10 implants were placed with a conventional delayed placement protocol, for example, 12 weeks after tooth extraction. At the baseline and at the annual re‐examinations, pain from implant regions, mobility, plaque, mucositis, and marginal bone levels were recorded. Biological and technical complications were registered. The patients evaluated the functional and aesthetic outcomes subjectively on a visual analogue scale after 3 and 10 years. Results: All implants were still in situ after 10 years. The cumulative implant survival rate was 100%. Two implant‐supported crowns were remade because of ceramic fractures. The 10‐year crown survival rate was 90%. No significant differences in implant survival rates were found between the early and delayed protocols, regarding plaque retention, mucositis, or marginal bone levels. After 10 years, the mean marginal bone loss at both sides of the implants was less than 1.0 mm in the two groups. During the 10‐year interval, 1 patient lost more than 1.5 mm of marginal bone, 3 patients lost between 1.0 mm and 1.4 mm of bone, and 16 patients lost less than 1.0 mm of bone as an average of the mesial and distal bone loss. Conclusions: This 10‐year prospective clinical trial demonstrated a 100% implant survival and a 90% crown survival. The average marginal bone level change was less than 1 mm, and there was no difference between early and delayed implant placement. Patient satisfaction with the implant‐supported single crowns reduced with time.     

One‐piece zirconia oral implants for single‐tooth replacement: Three‐year results from a long‐term prospective cohort study

Aim

This 3‐year report of a prospective long‐term cohort investigation aimed to evaluate the clinical and radiographic outcomes of a one‐piece zirconia oral implant for single‐tooth replacement.

Materials and Methods

Sixty‐five patients received a 1‐stage implant surgery with immediate temporization. Standardized radiographs were taken at implant insertion, after 1 year, and after 3 years to monitor peri‐implant bone levels. A univariate analysis of the association of different baseline parameters on marginal bone loss from implant insertion to 36 months was performed. Soft‐tissue parameters were evaluated at prosthesis insertion, after 6 months, after 1 year, and at the 3‐year follow‐up.

Results

After 3 years, six posterior site implants were lost, giving a cumulative survival rate of 90.8%. The mean marginal bone loss was 1.45 mm; 35% of the implants lost at least 2 mm bone, and 22% more than 3 mm. The univariate analysis did not identify any parameter associated with marginal bone loss. Probing depth, clinical attachment level, and bleeding index increased over 3 years, and plaque index decreased.

Conclusions

The low survival rate of the presented ceramic implant and especially the high frequency of advanced bone loss are noticeable but remain unexplained.     

Early loading of single crowns supported by 6‐mm‐long implants with a moderately rough surface: a prospective 2‐year follow‐up cohort study

Aim: To evaluate prospectively the clinical and radiographic outcomes after 2 years of loading of 6 mm long moderately rough implants supporting single crowns in the posterior regions. Material and methods: Forty SLActive Straumann^® short (6 mm) implants were placed in 35 consecutively treated patients. Nineteen implants, 4.1 mm in diameter, and 21 implants, 4.8 mm in diameter, were installed. Implants were loaded after 6 weeks of healing. Implant survival rate, marginal bone loss and resonance frequency analysis (RFA) were evaluated at different intervals. The clinical crown/implant ratio was also calculated. Results: Two out of 40 implants were lost before loading. Hence, the survival rate before loading was 95%. No further technical or biological complications were encountered during the 2‐year follow‐up. The mean marginal bone loss before loading was 0.34±0.38 mm. After loading, the mean marginal bone loss was 0.23±0.33 and 0.21±0.39 mm at the 1‐ and 2‐year follow‐ups. The RFA values increased between insertion (70.2±9) and the 6‐week evaluation (74.8±6.1). The clinical crown/implant ratio increased with time from 1.5 at the delivery of the prosthesis to 1.8 after 2 years of loading. Conclusion: Short implants (6 mm) with a moderately rough surface loaded early (after 6 weeks) during healing yielded high implant survival rates and moderate loss of bone after 2 years of loading. Longer observation periods are needed to draw more definite conclusions on the reliability of short implants supporting single crowns. To cite this article:
Rossi F, Ricci E, Marchetti C, Lang NP, Botticelli D. Early loading of single crowns supported by 6‐mm‐long implants with a moderately rough surface: a prospective 2‐year follow‐up cohort study.
Clin. Oral Impl. Res. 21 , 2010; 937–943.
doi: 10.1111/j.1600‐0501.2010.01942.x     

Influence of Apico‐Coronal Implant Placement on Post‐Surgical Crestal Bone Loss in Humans

Background: Contradictory results exist regarding influence of apico‐coronal implant placement on crestal bone levels. Methods: Complete charts of patients ≥18 years old with one or more dental implants were included. Demographic, medical, surgical, and prosthetic information was recorded. Implant bone levels were evaluated at initial placement, implant uncovery, prosthetic delivery, and 3 to 6, 7 to 11, and 12 to 18 months post‐implant placement. Results: Charts of 55 patients and 134 implants were included. At baseline, 19.5%, 67.3%, and 13.3% of implants were recorded as equicrestal, subcrestal, and supracrestal, respectively, on their mesial aspect, and 32.1%, 50.0%, and 17.9% on their distal aspect, respectively. At time of prosthetic delivery, mesial aspect implant position was equicrestal in 35.4%, subcrestal in 17.7%, and supracrestal in 46.9% of cases, whereas on their distal aspects, the same categorical positions were found in 28.4%, 21.1%, and 50.5% of implants. For the mesial aspect of the implant, 3‐ to 6‐, 7‐ to 11‐, and 12‐ to 18‐month intervals, and for the distal aspect of the implant, 7‐ to 11‐ and 12‐ to 18‐month intervals, along with diabetes (for both mesial and distal), were associated with a statistically more apical position of the bone compared with baseline. Although the odds ratio of a subcrestal implant position at follow‐up times was statistically greater for implants located subcrestally at surgery, linear measures of differential crestal bone loss (CBL) as a function of the categorical initial placement of the implant (supracrestal, equicrestal, subcrestal) at 3‐ to 6‐, 7‐ to 11‐, and 12‐ to 18‐month time points generally showed no significant differences among groups. Conclusion: A subcrestal position of the implant at time of surgery leads to reduced odds of having implant threads exposed; however, it is associated with similar linear CBL compared with an equicrestal or supracrestal surgical position.     

Vertical Osteoconductive Characteristics of Titanium Implants with Calcium‐Phosphate‐Coated Surfaces – A Pilot Study in Rabbits

Introduction: Osteoconductive characteristics of different implant surface coatings are in the focus of current interest. The aim of the present study was to compare the vertical osteoconductivity at the implant shoulder of supracrestal inserted calcium‐phosphate coated implants (SLA‐CaP) with conventional sand‐blasted/acid‐etched (SLA) implants in a rabbit model. Materials and Methods: SLA‐CaP and SLA implants were inserted bilaterally in the mandible of four rabbits in a split‐mouth design. The implants were placed 2 mm supracrestal. After 3 weeks, at the left and right implant shoulder, the percentage of linear bone fill (PLF) as well as bone‐implant contact (BIC‐D) were determined. Results: After 3 weeks, newly formed woven bone could be found at the shoulder of the most of both surface‐treated implants (75%). PLF was significantly higher in SLA‐CaP implants (11.2% vs. 46.5%; n = 8, p = .008). BIC‐D was significantly increased in the SLA‐CaP implants (13.0% vs. 71.4%; n = 8, p < .001) as well. Conclusion: The results of this study show for the first time that calcium‐phosphate coated surfaces on supracrestal inserted implants have vertical osteoconductive characteristics and increase the bone‐implant contact at the implant shoulder significantly in a rabbit model. In clinical long‐term settings, these implants may contribute to a better vertical bone height.     

Marginal Bone Loss in Implants Placed in the Maxillary Sinus Grafted With Anorganic Bovine Bone: A Prospective Clinical and Radiographic Study

Background: Sinus elevation is a reliable and often‐used technique. Success of implants placed in such situations, even with bone substitutes alone, prompted the authors of this study to strive for bone loss close to zero and research variables that cause higher or lower rates of resorption. The objective of this study is to evaluate survival rates and marginal bone loss (MBL) around implants placed in sites treated with maxillary sinus augmentation using anorganic bovine bone (ABB), and identify surgical and prosthetic prognostic variables. Methods: Fifty‐five implants were placed in 30 grafted maxillary sinuses in 24 patients. Periapical radiographs were evaluated immediately after implant placement (baseline), 6 months, and at the most recent follow‐up. MBL was calculated from the difference between initial and final measurements, taking into account a distortion rate for each radiograph compared with original implant measurements. Results: Survival rate was 98.2%, with only one implant lost (100% survival rate after loading) over a mean follow‐up time of 2.0 ± 0.9 years. MBL ranged from 0 to 2.85 mm: 75.9% of mesial sites and 83.4% of distal sites showed <1 mm of MBL, whereas 35.2% of mesial sites and 37% of distal sites exhibited no bone loss. MBL was significantly (P <0.05) greater in open‐flap compared with flapless surgery. Conclusions: Within the limitations of the present study, it was concluded that maxillary sinus elevation with 100% ABB gives predictable results, and that flapless surgery results in less MBL compared with traditional open‐flap surgery.     

Clinical and radiographic study of implant treatment outcome in periodontally susceptible and non-susceptible patients: a prospective long-term study

Objectives: To evaluate the implant survival rate, periodontal and radiographic parameters of non‐submerged screw implants with two different surfaces (TPS and SLA) in periodontally non‐susceptible patients (NSP) and in patients with chronic adult periodontitis (CAP) or with generalized aggressive periodontitis (GAP). Material and methods: In 110 healthy partially edentulous subjects, 68 patients with CAP and 16 patients with GAP, a total of 513 implants were installed and followed for on average 48.1±25.9 months. Only fixed partial dentures were used as suprastructures. All patients were offered a supportive periodontal maintenance program. Smoking habits, health impairment, plaque score, bleeding on probing (BOP), type of surface, bone score, bone loss on radiographs and the number of failed implants were noted. Results: Implant survival in the NSP and CAP group was 98% and 96% after 140 months (NS), but only 80% after 100 months in the GAP group (P=0.0026). The overall rate of implant loss was 4.7%, but 15.25% in the GAP group (6/16 patients). The average marginal bone loss for all implants was 0.12±0.71 mm on the mesial side and 0.11±0.68 mm on the distal side. Bone loss/year was 0.08±0.31 and 0.07±0.3 mm in the NSP group, but 0.17±0.2 and 0.17±0.19 mm in the GAP group. Only in the GAP group, was bone loss significantly related to BOP, age, inflammation, presence of plaque, probing depth. Implants with a TPS surface had a lower survival than implants with an SLA surface (93% vs. 97%; P=0.06), especially in the GAP group (80% vs. 83%; P=0.005). Smoking habits had a significant influence on implant survival only in the GAP group (P=0.07), declining in current smokers to 63%, and to 78% in former smokers. Overall, impaired general health had no significant influence (P=0.85). However, impaired health further reduced implant survival in the GAP group (survival: 71%). In a statistical model to predict the chance for implant failing, only periodontal classification (P=0.012) and implant surface type (P=0.027) were significant. Conclusion: Periodontally healthy patients and patients with CAP show no difference in peri‐implant variables and implant survival rate, but patients with GAP have more peri‐implant pathology, more marginal bone loss and a lower implant survival implant rate. SLA surface had a better prognosis than the TPS surface.     

Narrow‐ and regular‐diameter implants in the posterior region of the jaws to support single crowns: A 3‐year split‐mouth randomized clinical trial

Objectives

The objective of this 3‐year split‐mouth randomized controlled clinical study was to compare narrow‐diameter implants (NDIs) to regular‐diameter implants (RDIs) in the posterior region of the jaws (premolars and molars) in regards to (i) the marginal bone level (MBL) and (ii) implant and prosthesis survival and success rates.

Material and Methods

A total of 22 patients were included in the study. Each patient received at least one implant of each diameter (Ø3.3 and Ø4.1 mm), placed either in the maxilla or mandible to support single crowns. A total 44 implants (22 NDIs and 22 RDIs) were placed and included in the study. Twenty‐one implants were placed in the premolar, whereas 23 were placed in molar areas. Radiographic evaluations to access the MBL were performed immediately after implant placement, 1 and 3 years after implant loading. Peri‐implant clinical variables including probing pocket depth (PPD) and bleeding on probing (BoP) were obtained after crown delivery, 1 and 3 years after loading. Furthermore, the survival and success rates of the implants and prosthesis were also evaluated.

Results

Twenty patients were able to complete the study. There was no statistically significant difference regarding MBL between groups at implant placement (p = .084), 1‐year (p = .794) and 3‐year (p = .598) time intervals. The mean peri‐implant bone loss at 3‐year follow‐up was ?0.58 ± 0.39 mm (95% CI: ?0.751 to ?0.409) and ?0.53 ± 0.46 mm (95% CI: ?0.731 to ?0.329) for NDIs and RDIs, respectively. BoP was present at 15% and 10% of NDIs and RDIs, respectively, at 3‐year follow‐up. PPD >5 mm was observed in 5% and 0% of the implants of NDIs and RDIs, respectively, at 3‐year follow‐up. At the 3‐year examination, the implant success rates were in the NDIs and RDIs sites, respectively, 95% and 100%. The corresponding values for prosthesis success rates were 90% for NDIs and 95% for RDIs.

Conclusion

The present study demonstrated that NDIs placed to support single crowns in the posterior region did not differ to RDIs in regards to MBL, implant survival, and success rates.     

A 3‐year prospective radiographic evaluation of marginal bone level around different implant systems

Summary The aim of this study was to evaluate the change of marginal bone level radiographically around three different implant systems after 3 years in function. Fifty‐four patients were included and randomly assigned to three treatment groups of rough‐surface implants (TiUnite, n = 37), hybrid of smooth and rough‐surface implants (Restore, n = 38) and rough surface with microthread implants (Hexplant, n = 45). Clinical and radiographic examinations were conducted at the time of implant loading (baseline), 1 and 3 years after loading. A three‐level mixed‐effect analysis of covariance (ancova ) was used to test the significance of the mean marginal bone change of the three implant groups. A total 120 of 135 implants completed the study. None of the implants failed to integrate. Significant differences were noted in the marginal bone loss recorded for the three groups (P < 0·0001). At 3 years, the rough surface with microthread implants had a mean crestal bone loss of 0·59 ± 0·30 mm; the rough‐surface implants, 0·95 ± 0·27 mm; and the hybrid surface implants, 1·05 ± 0·34 mm. Within the limitations of this study, rough‐surface implants with microthread at the coronal part might have a long‐term positive effect in maintaining the marginal bone level against functional loading in comparison with implants without these two features.     

Factors influencing resonance frequency analysis assessed by Osstell™mentor during implant tissue integration: II. Implant surface modifications and implant diameter

Objectives: To monitor the development of the stability of Straumann^® tissue‐level implants during the early phases of healing by resonance frequency analysis (RFA) and to determine the influence of implant surface modification and diameter. Material and methods: A total of twenty‐five 10 mm length implants including 12 SLA RN ?4.1 mm implants, eight SLActive RN ?4.1 mm implants and five SLA WN ?4.8 mm implants were placed. Implant stability quotient (ISQ) values were determined with Osstell^?mentor at baseline, 4 days, 1, 2, 3, 4, 6, 8 and 12 weeks post‐surgery. ISQ values were compared between implant types using unpaired t‐tests and longitudinally within implant types using paired t‐tests. Results: During healing, ISQ decreased by 3–4 values after installation and reached the lowest values at 3 weeks. Following this, the ISQ values increased steadily for all implants and up to 12 weeks. No significant differences were noted over time. The longitudinal changes in the ISQ values showed the same patterns for SLA implants, SLActive implants and WB implants. At placement, the mean ISQ values were 72.6, 75.7 and 74.4, respectively. The mean lowest ISQ values, recorded at 3 weeks, were 69.9, 71.4 and 69.8, respectively. At 12 weeks, the mean ISQ values were 76.5, 78.8 and 77.8, respectively. The mean ISQ values at all observation periods did not differ significantly among the various types. Single ISQ values ranged from 55 to 84 during the entire healing period. Pocket probing depths of the implants ranged from 1 to 3 mm and bleeding on probing from 0 to 2 sites/implant post‐surgically. Conclusions: All ISQ values indicated the stability of Straumann^® implants over a 12‐week healing period. All implants showed a slight decrease after installation, with the lowest ISQ values being reached at 3 weeks. ISQ values were restored 8 weeks post‐surgically. It is recommended to monitor implant stability by RFA at 3 and 8 weeks post‐surgically. However, neither implant surface modifications (SLActive) nor implant diameter were revealed by RFA. To cite this article:
Han J, Lulic M, Lang NP. Factors influencing resonance frequency analysis assessed by Osstell^?mentor during implant tissue integration: II. Implant surface modifications and implant diameter.
Clin. Oral Impl. Res. 21 , 2010; 605–611.
doi: 10.1111/j.1600‐0501.2009.01909.x     

Dental implants in diabetic patients: retrospective cohort study reporting on implant survival and risk indicators for excessive marginal bone loss at 5 years

More studies evaluating the outcome of dental implant restorations in diabetics are needed. To investigate the outcome of immediate function implant rehabilitations in diabetic patients. This retrospective cohort study included 70 diabetic patients (type 1 = six patients; type 2 = 64 patients; 33 females and 37 males, mean age=59 years), rehabilitated with 352 implants. Primary outcome measure was implant survival estimated at 5 years through the Kaplan–Meier product limit estimator using the patient as unit of analysis (first implant failure as reference); secondary outcome measures were marginal bone loss and biological complications. Risk indicators associated with bone loss >2·0 mm were tested in a multivariate logistic regression model. The level of significance considered was 5%. Seven patients were lost to follow‐up (10%). Seven patients lost ten implants rendering a global implant cumulative survival rate for diabetic patients of 89·8% (type 1 = 80·0%; type 2 = 90·5%). The average (95% confidence interval) marginal bone loss at 1 and 5 years was 1·64 mm (0·00;3·32) and 2·55 mm (1·38;3·72) for type 1 diabetic patients, 0·79 mm (0·59;1·00) and 1·45 mm (1·09;1·82) for type 2 diabetic patients and 0·88 mm (0·65;1·10) and 1·56 mm (1·21;1·91) overall. Biological complications occurred in seven patients. Female gender (OR = 28·1) and smoking habits (OR = 10·3) were risk indicators for marginal bone loss >2·0 mm at 5 years when controlled for other variables of interest. Implant rehabilitations represent a valid treatment for diabetic patients, with a good risk/benefit ratio. Female gender and smoking habits were risk indicators for a higher marginal bone resorption at 5 years.