Novel Implant Design Improves Implant Survival in Multirooted Extraction Sites: A Preclinical Pilot Study

Background: The primary aim is to evaluate clinical, radiographic, and histologic parameters of novel implants with “three roots” design that were inserted into fresh multirooted extraction sockets. A secondary aim is to compare this new implant to standard root‐form dental implants. Methods: Immediate implantation of novel or standard design 6 × 6‐mm implants was performed bilaterally into multirooted sockets in mandibles of mini‐pigs. Twelve weeks later, clinical, radiographic, stability, histomorphometric, and microcomputed tomography (micro‐CT) analyses were performed. Results: Survival rates were significantly higher in the test implants compared with control (92.8% versus 33.3%, respectively; P <0.001). Bone loss was greater in the control compared with the test by sounding (mean 3.42 ± 0.68 versus 1.96 ± 0.34 mm) and radiography (mean 3.35 ± 0.62 versus 2.27 ± 0.33 mm). Histologic and micro‐CT analyses demonstrated bone fill in the inner part of the test implants. Moreover, bone‐to‐implant contact was higher in the test implants (55.50% ± 3.68% versus 42.47% ± 9.89%). Contrary to the clinical, radiographic, and histomorphometric results, resonance frequency analysis measurements were greater in the control group (77.74 ± 3.21 implant stability quotient [ISQ]) compared with the test group (31.09 ± 0.28 ISQ), P = 0.008. Conclusions: The novel design implants resulted in significantly greater survival rate in multirooted extraction sites. Further studies will be required to validate these findings.     

One-year clinical and radiographic assessment of fluoride-enhanced implants on immediate non-functional loading in posterior maxilla and mandible: a pilot prospective clinical series study

Objective: The functional, esthetic, and psychological problems of 3–6 months of edentulousness and also discomfort of two‐stage surgery might cause many patients to avoid implant‐supported restorations. Therefore, the immediate non‐functional loading protocol might be of value. Methods: Twenty Astra Tech implants, 11–13 mm in length and 3.5–4 mm in diameter, were placed in maxillary and mandibular posterior sites of 10 healthy patients (two for each) with adequate alveolar bone. Temporary prostheses were relieved of all centric and eccentric contacts. Functional permanent prostheses were fabricated 13 weeks postoperatively. Clinical and radiographic examinations (including the implant stability quotient [ISQ]) were carried out immediately after implantation and 3, 6, and 12 months postoperatively. Results: A 100% success rate was observed within 1 year. The plaque and bleeding indices, and pocket‐probing depths did not show a significant change throughout the study. The ISQ values after implant insertion, and 3, 6, and 12 months later were respectively 76.6 ± 6.57, 77.6 ± 10.54, 81.8 ± 6.8, and 82.43 ± 3.7. The increase was statistically significant (P=0.004) according to the Freidman test. The ISQ values measured after the implant insertion were significantly different from those measured in the sixth and 12th postoperative months (P<0.008) according to the Wilcoxon signed‐ranks test. The mean crestal alveolar bone resorption values in the third, sixth, and 12th postoperative months were 0.4 ± 0.55, 0.48 ± 0.37, and 0.48 ± 0.21 mm, respectively; and the change in marginal alveolar bone loss was not significant according to the Freidman test. Conclusion: Within the limitations of this pilot study, non‐functional immediate loading might meet the expectations of both the patients and clinicians. To cite this article:
Rismanchian M, Fazel A, Rakhshan V, Eblaghian G. One‐year clinical and radiographic assessment of fluoride‐enhanced implants on immediate non‐functional loading in posterior maxilla and mandible: a pilot prospective clinical series study.
Clin. Oral Impl. Res. xx , 2011; 000–000.
doi: 10.1111/j.1600‐0501.2010.02134.x     

A prospective,controlled clinical trial evaluating the clinical and radiological outcome after 3 years of immediately placed implants in sockets exhibiting periapical pathology

Objectives: The aim of the present study was to compare the clinical and radiological outcome of immediately placed implants in sockets with or without periapical pathology 3 years after implant placement. Materials and methods: Twenty‐nine patients with immediate implant placement were clinically and radiologically followed 3 years after implant placement (test group: 16 patients without periapical pathology, control group: 13 patients with periapical pathologies). Clinical (full‐mouth bleeding score, full‐mouth plaque score, clinical attachment level measurements and width of keratinized mucosa buccaly of the implant) and radiological parameters (vertical distance from the implant shoulder to the first bone‐to‐implant contact [IS‐BIC]) were assessed. Both 95% confidence intervals, as well as results of statistical tests (one‐sample, two‐sample and paired t‐test) were provided. Results: The implant survival rate was 100% for all 29 implants after 3 years. The clinical and radiological parameters showed no statistically significant difference between the test and the control group at 3 years (two‐sample t‐test). The IS‐BIC was between 1.54 ± 0.88 mm (mesial, test) and 1.69 ± 0.92 mm (distal, test). Between the 1‐ and 3‐year visit the IS‐BIC increased in both groups significantly on one side of the implant: 0.30 ± 0.37 mm (mesial, test) and 0.33 ± 0.43 mm (distal, control) (one‐sample t‐test). None of the 13 examined radiographs of implants immediately placed in sockets with periapical pathologies revealed retrograde peri‐implantitis after 3 years. Conclusion: It is concluded within the limitations of this study, that after careful debridement of the extraction socket, immediate placement of implants into sites with periapical pathologies can be a successful treatment modality for at least 3 years with no disadvantages in clinical and radiological parameters to immediately placed implants into healthy sockets. To cite this article:
Truninger TC, Philipp AOH, Siegenthaler DW, Roos M, Hämmerle CHF, Jung RE. A prospective, controlled clinical trial evaluating the clinical and radiological outcome after 3 years of immediately placed implants in sockets exhibiting periapical pathology.

Clin. Oral Impl. Res. 22 , 2011; 20–27.
doi: 10.1111/j.1600‐0501.2010.01973.x     

Effect of platform switching on peri-implant bone levels: a randomized clinical trial

Objective: The concept of platform switching has been introduced to implant dentistry based on observations of reduced peri‐implant bone loss. However, randomized clinical trials are still lacking. This study aimed to test the hypothesis that platform switching has a positive impact on crestal bone‐level changes. Material and methods: Two implants with diameters of 4 mm were inserted epicrestally into one side of the posterior mandibles of 25 subjects. After 3 months of submerged healing, the reentry surgery was performed. On the randomly placed test implant, an abutment 3.3 mm in diameter was mounted, resulting in a horizontal circular step of 0.35 mm (platform switching). The control implant was straight, with an abutment 4 mm in diameter. Single‐tooth crowns were cemented provisionally. All patients were monitored at short intervals over the course of 1 year. Standardized radiographs and microbiological samples from the implants' inner spaces were obtained at baseline (implant surgery), and after 3, 4, and 12 months. Results: After 1 year, the mean radiographic vertical bone loss at the test implants was 0.53±0.35 mm and at the control implants, it was 0.58±0.55 mm. The mean intraindividual difference was 0.05±0.56 mm, which is significantly <0.35 mm (P=0.0093, post hoc power 79.9%). The crestal bone‐level changes depended on time (P<0.001), but not on platform switching (P=0.4). The implants' internal spaces were contaminated by bacteria, with no significant differences in the total counts between the test and the control at any time point (P=0.98). Conclusions: The present randomized clinical trial could not confirm the hypothesis of a reduced peri‐implant bone loss at implants restored according to the concept of platform switching. To cite this article:
Enkling N, Jöhren P, Klimberg V, Bayer S, Mericske‐Stern R, Jepsen S. Effect of platform switching on peri‐implant bone levels: a randomized clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 1185–1192.
doi: 10.1111/j.1600‐0501.2010.02090.x     

The clinical and radiographic outcome of implants placed in the posterior maxilla with a guided flapless approach and immediately restored with a provisional rehabilitation: a randomized clinical trial

Objectives: To evaluate and compare the outcome of dental implants placed using a flapless protocol and immediate loading with a conventional protocol and loading after 6 weeks. Materials and methods: Fourteen patients with bilateral maxillary edentulous areas were treated using Straumann SLA‐implants. Using a randomized split‐mouth design, implants were placed in one side of the maxilla using a stereolithographic surgical guide for flapless surgery and immediately loaded on temporary abutments with a bridge (test). Implants in the other side were placed using the conventional protocol and loaded after 6 weeks of healing (control). Clinical and radiographic evaluation of peri‐implant tissues was performed at time of implant surgery, and after 1 week, 6 weeks, 3, 6, 12 and 18 months. Results: A total of 70 implants were placed (36 test and 34 control). One implant (test) was lost after 3 months, resulting in a survival rate of 97.3% for the test implants and 100% for the control implants. Marginal bone levels were not statistically significantly different between the test and control implants but at baseline the marginal bone level was significantly lower compared to the other evaluation periods (P < 0.05). The mean bone level for test and control implants was 1.95 mm ± 0.70 and 1.93 mm ±0.42 after 18 months, respectively. There was a significant change in height of the attached mucosa at implants placed with a conventional flap between post‐operative and 1 week and between 1 week and 6 weeks. Statistically significant differences were found between the test side and the control side for opinion about speech, function, aesthetics, self‐confidence and overall appreciation the first 6 weeks. Conclusion: Implants can successfully integrate in the posterior maxilla using a flapless approach with immediate loading similar to a conventional protocol. The mucosal tissues around implants placed with a conventional flap changed significantly compared with flapless placed implants. To cite this article:
Van de Velde T, Sennerby L, De Bruyn H. The clinical and radiographic outcome of implants placed in the posterior maxilla with a guided flapless approach and immediately restored with a provisional rehabilitation: a randomized clinical trial.
Clin. Oral Impl. Res. 21 , 2010; 1223–1233.
doi: 10.1111/j.1600‐0501.2009.01924.x     

Factors influencing resonance frequency analysis assessed by Osstell™mentor during implant tissue integration: I. Instrument positioning,bone structure,implant length

Aim: To monitor longitudinally the development of implant stability of SLA Straumann^® tissue‐level implants using resonance frequency analysis (RFA) and to determine the influence of instrument positioning, bone structure and implant length on the assessment of RFA. Material and methods: Thirty‐two healthy adult patients received either 8 mm, ?4.1 mm Straumann^® Standard Plus tissue‐level implants (n=16: Group A) or 10 mm, ?4.1 mm Straumann^® Standard Plus tissue‐level implants (n=16: Group B). During healing, RFA was performed on Weeks 0,1, 2, 3, 4, 5, 6, 8 and 12. The implants were restored after 10 weeks (impression taking) and 12 weeks. In addition, probing depth, presence of plaque and bleeding on probing were assessed. Implant stability quotient (ISQ) values of Groups A and B were compared using unpaired t‐tests and longitudinally applying paired t‐tests between Week 0 and the subsequent time points. Results: Positioning of the Osstell^?mentor device did not affect the ISQ values. Generally, ISQ values increased continuously during healing from a mean of 65.1 (SD 16.97) to 74.7 (SD 5.17) (significantly from Week 0 to Weeks 6, 8 and 12). Lower bone density (Type III or IV) resulted in significantly lower ISQ values up to Week 8. Implant length affected the increase in ISQ values over time. While no significant increase was observed with 10 mm implants, ISQ values of 8 mm implants increased significantly from Week 0 to Weeks 6, 8 and 12. Conclusions: Using Osstell^?mentor, ISQ values are reproducible irrespective of instrument positioning. ISQ values are affected by the bone structure and implant length. Hence, no predictive values can be attributed to implant stability. To cite this article:
Sim CPC, Lang NP. Factors influencing resonance frequency analysis assessed by Osstell^?mentor during implant tissue integration: I. Instrument positioning, bone structure, implant length.
Clin. Oral Impl. Res. 21 , 2010; 598–604.
doi: 10.1111/j.1600‐0501.2009.01878.x     

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     

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     

A 2-year prospective study on immediate loading with fluoride-modified implants in the edentulous mandible

Objectives: Chemically modified surfaces were introduced during the last decade to improve indications for implant treatment. The fluoride‐modified implant (Osseospeed^®) was launched in 2004 and clinical studies suggest a more rapid bone formation and stronger bone to implant contact. However, limited clinical data are available on marginal bone loss and the outcome after >1 year under immediate loading conditions is not fully understood. Hence, the purpose of this prospective study was to present implant survival and marginal bone level data when fluoride‐modified implants are supporting a fully functional rehabilitation from the day after surgery in the completely edentulous mandible. Materials and methods: Twenty‐five patients, completely edentulous in the mandible, were consecutively treated with five fluoride‐modified implants that were functionally loaded with a provisional screw retained restoration. Marginal bone loss was measured from day of surgery to 3, 6, 12 and 24 months. Implants were considered successful after 24 months if radiographic bone loss did not exceed 1 mm and no pain or mobility was caused under a torque of 20 N cm. Statistical analysis was carried out on both patient and implant levels. Results: All implants survived and mean bone loss on implant level after 3, 6, 12 and 24 months was 0.14, 0.13, 0.11 and 0.11 mm, respectively. Bone loss was only statistically significant between baseline and 3 months (P<0.001) and remained unchanged afterward. None of the implants lost >1 mm of bone after 2 years. On the patient level, the mean bone loss after 2 years was 0.12 mm (SD 0.14; range ?0.06 to 0.55) with probing pocket depth 2.45 mm (SD 0.43; range 1.3–3.1) and bleeding index 0.55% (SD 0.34; range 0–1). Conclusion: Immediate loading of fluoride‐modified implants is a predictable treatment yielding a high survival and success rate after 2 years. To cite this article:
Collaert B, Wijnen L, De Bruyn H. A 2‐year prospective study on immediate loading with fluoride‐modified implants in the edentulous mandible.
Clin. Oral Impl. Res. 22 , 2011; 1111–1116.
doi: 10.1111/j.1600‐0501.2010.02077.x     

Mandibular single‐implant overdentures: preliminary results of a randomised‐control trial on early loading with different implant diameters and attachment systems

Objectives: To determine surgical and prosthodontic outcomes of mandibular single‐implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. Materials and methods: Thirty‐six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6‐week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8‐mm‐wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non‐parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). Results: Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Conclusions: Mandibular single‐implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems. To cite this article:
Alsabeeha NHM, Payne AGT, De Silva RK, Thomson WM. Mandibular single‐implant overdentures: preliminary results of a randomised‐control trial on early loading with different implant diameters and attachment systems.
Clin. Oral Impl. Res. 22 , 2011; 330–337.
doi: 10.1111/j.1600‐0501.2010.02004.x     

Relationship between the bone density estimated by cone-beam computed tomography and the primary stability of dental implants

Objectives: The aims of this study were to objectively assess bone quality with density values obtained by cone‐beam computed tomography (CBCT) and to determine the correlations between bone density and primary stability of dental implants. Material and methods: Eighteen Straumann implants were inserted into 18 fresh femoral heads of swine. The bone densities of implant recipient sites were preoperatively determined by the density value using CBCT. The maximum insertion torque value of each implant was recorded using a digital torque meter. Resonance frequency, which represented a quantitative unit called the implant stability quotient (ISQ), was measured using an Osstell^® Mentor immediately after the implant placement. Spearman's correlation coefficient was calculated to evaluate the correlations among density values, insertion torques, and ISQs at implant placement. Results: The density values ranged from 98 to 902. The mean density value, insertion torque, and ISQ were 591±226, 13.4±5.2 Ncm, and 67.1±8.1, respectively. Statistically significant correlations were found between the density values and insertion torque (r_s=0.796, P<0.001), density values and ISQ (r_s=0.529, P=0.024), and insertion torque and ISQ (r_s=0.758, P<0.001). Conclusions: The bone quality evaluated by specific CBCT showed a high correlation with the primary stability of the implants. Hence, preoperative density value estimations by CBCT may allow clinicians to predict implant stability. Whether the density values obtained by the CBCT device used in the present study could be applied to other devices requires further elucidation. To cite this article:
Isoda K, Ayukawa Y, Tsukiyama Y, Sogo M, Matsushita Y, Koyano K. Relationship between the bone density estimated by cone‐beam computed tomography and the primary stability of dental implants.
Clin. Oral Impl. Res. 23 , 2012; 832–836
doi: 10.1111/j.1600‐0501.2011.02203.x     

Stability, marginal bone loss and survival of standard and modified sand-blasted, acid-etched implants in bilateral edentulous spaces: a prospective 15-month evaluation

Objectives: Chemical modification of the already proven sand‐blasted and acid‐etched (SLA) implant had increased its surface wettability and consequent early‐term osseointegration characteristics. The aim of this clinical trial was to compare the stability changes, success, survival, peri‐implant parameters and marginal bone loss (MBL) of the early‐loaded standard (SLA) and modified sand‐blasted, acid‐etched (modSLA) implants. Material and methods: A total of 96 SLA and modSLA implants were placed in a bi‐lateral, cross‐arch position to the jaws of 22 patients. Resonance frequency analysis (RFA) was used to measure the implant stability in the surgery and following healing after 1, 3 and 6 weeks. At the stage of loading, a panoramic X‐ray was obtained and RFA measurement was repeated for all implants. Implants were restored by metal–ceramic crowns and followed for 1 year to determine the success, survival rate, peri‐implant parameters and MBL. Results were compared by one‐ and two‐way ANOVA, log‐rank test and generalized linear mixed models (P<0.05). Results: One modSLA implant was lost after 3 weeks following the surgery yielding to a 100 and 97.91% success rate for SLA and modSLA implants, respectively (P=0.323). At the loading stage, modSLA implants showed significantly lower MBL (0.18 ± 0.05 mm) than SLA implants (0.22 ± 0.06 mm; P=0.002). In the loading stage, RFA value of the modSLA implants (60.42 ± 6.82) was significantly higher than the both implant types in the surgical stage (55.46 ± 8.29 and 56.68 ± 8.19), and following 1 (56.08 ± 7.01 and 55.60 ± 9.07) and 3 weeks of healing (55.94 ± 5.95 and 55.40 ± 6.50 for SLA and modSLA implants, respectively). Conclusions: modSLA implants demonstrated a better stability and a reduced MBL at the loading stage. Both SLA and modSLA implants demonstrated a favorable success and survival at the end of 15‐month follow‐up. To cite this article :
Karabuda ZC, Abdel‐Haq J. Arιsan V. Stability, marginal bone loss and survival of standard and modified sand‐blasted, acid‐etched implants in bilateral edentulous spaces: a prospective 15‐month evaluation.
Clin. Oral Impl. Res. 22 , 2011; 840–849
doi: 10.1111/j.1600‐0501.2010.02065.x     

Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures

Objectives: To determine the primary stability of the Southern wide diameter (8 mm) implants, Neoss regular diameter (4 mm) implants, and Southern regular diameter (3.75 mm) implants placed in the midline of edentulous mandibles for single‐implant overdentures. Variables related to host site and implant characteristics were investigated to determine their influence on the primary stability of the implants. Materials and methods: A total of 36 implants were placed in the midline symphysis of the edentulous mandibles of 36 participants. Their primary stability was then measured using the magnetic Osstell mentor device. Analysis of variance (ANOVA) was used to compare the mean implant stability quotient (ISQ) scores with one‐way ANOVA for multiple comparisons. Results: The highest measurement (ISQ) of primary stability was for the Southern 8 mm wide diameter implants (84.8, SD 9.8), followed by the Neoss 4 mm regular diameter (82.3, SD 4.8) implants and the Southern 3.75 mm regular diameter implants (75.3, SD 8.4), respectively. The Southern 3.75 mm regular diameter implants had a significantly lower mean ISQ value than the same system 8 mm wide diameter (P=0.004) and the Neoss 4 mm regular diameter implants (P=0.03). No significant differences were observed between the 8 mm and the 4 mm diameter implants (P>0.05). Conclusions: Host‐site variables such as age, gender, bone volume, and quality do not appear to influence the primary stability of the implants. No clear correlation was established between ISQ values and implant diameter. To cite this article:
Alsabeeha NHM, De Silva RK, Thomson WM, Payne AGT. Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures.
Clin. Oral Impl. Res. 21 , 2010; 563–566.
doi: 10.1111/j.1600‐0501.2009.01890.x     

Immediate and early loading of Straumann implants with a chemically modified surface (SLActive) in the posterior mandible and maxilla: 1-year results from a prospective multicenter study

Objective: Immediate and early loading of implants can simplify treatment and increase patient satisfaction. This 3‐year randomized‐controlled trial will therefore evaluate survival rates and bone‐level changes with immediately and early loaded Straumann implants with the SLActive surface. Material and methods: Partially edentulous patients ≥18 years of age were enrolled. Patients received a temporary restoration (single crown or two to four unit fixed partial denture) out of occlusal contact either immediately (immediate loading) or 28–34 days later (early loading group), with permanent restorations placed 20–23 weeks after surgery. The primary endpoint was change in crestal bone level from baseline (implant placement) to 12 months; the secondary variables were implant survival and success rates. Results: A total of 383 implants (197 immediate and 186 early) were placed in 266 patients; 41.8% were placed in type III and IV bone. The mean patient age was 46.3±12.8 years. Four implants failed in the immediate loading group and six in the early loading group, giving implant survival rates of 98% and 97%, respectively (P=NS). There were no implant failures in type IV bone. The overall mean bone level change from baseline to 12 months was 0.77±0.93 mm (0.90±0.90 and 0.63±0.95 mm in the immediate and early groups, respectively; P<0.001). However, a significant difference in implantation depth between the two groups (P<0.0001) was found. After adjusting for this slight difference in initial surgical placement depth, time to loading no longer had a significant influence on bone‐level change. Significant influence was found for: center (P<0.0001), implant length (P<0.05) and implant position (P<0.0001). Bone gain was observed in approximately 16% of implants. Conclusions: The results demonstrated that Straumann implants with the SLActive surface are safe and predictable when used in immediate and early loading procedures. Even in poor‐quality bone, survival rates were comparable with those from conventional or delayed loading. The mean bone‐level change was not deemed to be clinically significant and compared well with the typical bone resorption observed in conventional implant loading.     

Long-term follow-up of turned single implants placed in periodontally healthy patients after 16-22 years: radiographic and peri-implant outcome

Objectives: Retrospectively evaluate the survival, radiographic and peri‐implant outcome of single turned Brånemark^? implants after at least 16 years. Materials and methods: From 134 patients (C‐group), 101 could be contacted concerning implant survival and 50 (59 remaining implants) were clinically examined (I‐group). Marginal bone level was radiographically measured from the implant–abutment junction at baseline (=within 6 months after abutment connection) and 1–4, 5–8 and 16–22 years post‐operatively. Probing depth, gingival and plaque index were measured. Marginal bone‐level changes were analyzed using Friedman's and Wilcoxon's signed ranks tests. Spearman's correlations between radiographic and clinical parameters were calculated. Results: In the C‐group, 13 out of 166 implants in 11 out of 134 patients failed (CSR=91.5%). In the I‐group (28 males–22 females; mean age 23.9 years at baseline; range 14–57), the mean follow‐up was 18.4 years (range 16–22). The mean bone level was 1.7±0.88 mm (range ?0.8 to 5) after 16–22 years. Changes in the mean marginal bone level were statistically significant between baseline and the second measuring interval (1–4 years). Thereafter, no significant differences could be demonstrated. The mean interproximal probing depth, gingival and plaque indices were 3.9±1.27 mm, 1.2±0.81 and 0.2±0.48, respectively. Probing depth was moderately correlated with gingival inflammation (r=0.6; P<0.001) but not with bone level (P>0.05). 81.4% of the implants had a bone level ≤2nd thread and 91.5% had a probing depth ≤5 mm. 76.3% had both bone level ≤2nd thread and probing depth ≤5 mm. Conclusions and clinical implications: The single turned Brånemark^? implant is a predictable solution with high clinical survival and success rates. In general, a steady‐state bone level can be expected over decades, with minimal signs of peri‐implant disease. A minority (5%), however, presents with progressive bone loss. To cite this article :
Dierens M, Vandeweghe S, Kisch J, Nilner K, De Bruyn H. Long‐term follow‐up of turned single implants placed in periodontally healthy patients after 16–22 years: radiographic and peri‐implant outcome.
Clin. Oral Impl. Res. 23 , 2012; 197–204. doi: 10.1111/j.1600‐0501.2011.02212.x     

Stability and marginal bone level measurements of unsplinted implants used for mandibular overdentures: a 1-year randomized prospective clinical study comparing early and conventional loading protocols

Objectives: The aim of this study was to compare the performance of two non‐splinted implants used as retention for a mandibular overdenture when applying conventional or early loading protocols. Material and methods: Twenty edentulous patients were treated with two unsplinted and non‐submerged implants (15 mm long, TiUnite RP, Brånemark System) in the anterior mandible. The patients were randomly allotted into two groups: (i) test group (Group A), in which the overdenture was connected 1 week after surgery, and (ii) control group (Group B), in which the overdenture was connected after 12 weeks of healing. Resonance frequency analyses (RFA) for implant stability measurements were performed at implant surgery and after 1, 3, 6, 9 and 12 months. Marginal bone levels were evaluated at implant surgery and after 6 and 12 months. Results: No implant from either group was lost and all implants showed less than 1 mm of marginal bone resorption during the first year. The mean implant stability quotient (ISQ) values at implant surgery were 76.2±2.8 for Group A and 75.6±4.5 for Group B. The 12‐month measurements showed 76.4±2.5 ISQ and 76.4±2.8 ISQ for Groups A and B, respectively. There were no statistically significant changes between or within the groups with time. There were no differences in marginal bone loss, which was on average 0.3 mm for both groups after 1 year. Conclusion: Although a limited number of patients were followed for 1 year only, the results of the present study indicate that early loading of two unsplinted 15 mm long implants with an overdenture does not negatively affect implant stability or marginal bone conditions when compared with implants subjected to 12 weeks of healing before loading.     

Role of Clinician's Experience and Implant Design on Implant Stability. An Ex Vivo Study in Artificial Soft Bones

Objectives: Clinical experience in implant placement is important in order to prevent implant failures. However, the implant design affects the primary implant stability (PS) especially in poor quality bones. Therefore, the aim of this study was to compare the effect of clinician surgical experience on PS, when placing different type of implant designs. Methods: A total of 180 implants (90 parallel walled‐P and 90 tapered‐T) were placed in freshly slaughtered cow ribs. Bone quality was evaluated by two examiners during surgery and considered as ‘type IV’ bone. Implants (ø 5 mm, length: 15 mm, Osseotite, BIOMET 3i, Palm Beach Gardens, FL, USA) were placed by three different clinicians (master/I, good/II, non‐experienced/III, under direct supervision of a manufacturer representative; 30 implants/group). An independent observer assessed the accuracy of placement by resonance frequency analysis (RFA) with implant stability quotient (ISQ) values. Two‐way analysis of variance (ANOVA) and Tukey's post hoc test were used to detect the surgical experience of the clinicians and their interaction and effects of implant design on the PS. Results: All implants were mechanically stable. The mean ISQ values were: 49.57(± 18.49) for the P‐implants and 67.07(± 8.79) for the T‐implants. The two‐way ANOVA showed significant effects of implant design (p < .0001), clinician (p < .0001), and their interaction (p < .0001). The Tukey's multiple comparison test showed significant differences in RFA for the clinician group I/II (p = .015) and highly significant (p < .0001) between I/III and II/III. The P‐implants presented (for I, II, and III) mean ISQ values 31.25/49.18/68.17 and the T‐implants showed higher ISQ values, 70.15/62.08/68.98, respectively. Clinicians I and II did not show extreme differences for T‐implants (p = .016). In contrast, clinician III achieved high ISQ values using P‐ and T‐implants following the exact surgical protocol based on the manufacturer guidelines. T‐implants provided high stability for experienced clinicians compared with P‐implants. Conclusion: T‐implants achieved greater PS than the P‐implants. All clinicians consistently achieved PS; however, experienced clinicians achieved higher ISQ values with T‐implants in poor quality bone.     

A randomized clinical 1‐year trial comparing two types of non‐submerged dental implants

Objectives: This study compared the implant stability and clinical outcomes obtained with two types of non‐submerged dental implants that have different thread designs and surface treatments. Materials and methods: A randomized clinical trial with 1 year of follow‐up was performed on 56 participants with 75 implants (control group, 36 implants in 28 subjects; experimental group, 39 implants in 28 subjects). The experimental group received the Osstem SSII Implant system; the control group received the Standard Straumann^® Dental Implant System. The diameter and length of the fixture were uniform at 4.1 mm and 10 mm and all the implants restored the unilateral loss of one or two molars from the mandible. To compare implant stability, the peak insertion torque, implant stability quotient (ISQ), and periotest value (PTV) were evaluated during surgery, and at 4 and 10 weeks after surgery. To compare marginal bone loss, standard periapical radiographs were obtained during surgery, and at 10 weeks and 1 year after surgery. Results: This study showed statistically significant differences between the two groups in peak insertion torque (P=0.009) and ISQ (P=0.003) but not in PTV (P=0.097) at surgery. In contrast, there was no statistically significant difference in the pattern of change of ISQ during the 10 weeks after surgery (P=0.339). For marginal bone loss, no significant difference was observed between the control and the experimental groups before functional loading (P=0.624), but after 1 year of follow‐up, a borderline difference was observed (P=0.048). Conclusion: The success rate after 1 year of follow‐up was 100% for both implant system despite the presence of a significant difference in implant stability during surgery. There was a borderline difference in marginal bone loss after 1 year of follow‐up. To cite this article:
Park J‐C, Ha S‐R, Kim S‐M, Kim M‐J, Lee J‐B, Lee J‐H. A randomized clinical 1‐year trial comparing two types of non‐submerged dental implant.
Clin. Oral Impl. Res. 21 , 2010; 228–236.
doi: 10.1111/j.1600‐0501.2009.01828.x     

Transmucosal healing around peri‐implant defects: crestal and subcrestal implant placement in dogs

Objective: This study was designed to evaluate the transmucosal healing response of implants placed with the junction of the smooth surfaces, either crestal or subcrestal, into simulated extraction defects after healing periods of 1 and 3 months. Materials and methods: A total of 23 Straumann SP ?3.3 mm NN, SLA^® 10 mm implants were placed in the mandibular premolar regions of three greyhound dogs 3 months after the teeth were removed. Five control implants were placed at the crestal bone level, and test implants with surgically created peri‐implant defects of 1.25 mm wide × 5 mm depth were placed either at the crestal (nine implants) or at the 2 mm subcrestal (nine implants) bone level. Implants on the right side were placed 1 month before the dogs were sacrificed, and implants on the left side were placed 3 months before sacrifice. All dogs had daily plaque control following surgery and were sacrificed 3 months after implant placement for histological and histometric analyses. Results: Mesial–distal ground sections of the control and test implant specimens showed a greater %BIC in the coronal defect region after 3 months of healing. This healing response was incomplete for the test implants compared with the control implants after a 1‐month healing period. The histometric measurements for test implants placed at the crestal bone level or 2 mm subcrestal with surgically created peri‐implant defects were more coronal or closer to the implant margin compared with the control implants. Additionally, the degree of osseointegration between the newly formed bone and the implant surface was similar between the test implants. Conclusion: Peri‐implant defects of 1.25 mm width healed with spontaneous bone regeneration around implants placed transmucosally at crestal or 2 mm subcrestal with a high degree of osseointegration after a 3‐month healing period. To cite this article:
Tran BLT, Chen ST, Caiafa A, Davies HMS, Darby IB. Transmucosal healing around peri‐implant defects: crestal and subcrestal implant placement in dogs.
Clin. Oral Impl. Res. 21 , 2010; 794–803.
doi: 10.1111/j.1600‐0501.2010.01911.x     

Initial stability and bone strain evaluation of the immediately loaded dental implant: an in vitro model study

Objectives: The aim of this study was to evaluate the effects of cortical bone thickness and trabecular bone elastic modulus on the strain in the bone surrounding an immediately loaded implant. We also examined the correlations between bone structure and the following indices of primary implant stability: insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ). Material and methods: The ITV, PTV, and ISQ were measured in 24 artificial jaw bone models representing cortical bone with four thicknesses (0, 1, 2, and 3 mm) and trabecular bone with four elastic moduli (137, 47.5, 23, and 12.4 MPa). Two loading conditions were applied (force of 130 N applied vertically and at 45° laterally), and the strains in the crestal region were measured by rosette strain gauges with a data acquisition system. Results: When the cortical bone thickness and the elastic modulus of trabecular bone decreased, the bone strains increased by 10.3–52.1% and 39–73.1%, respectively, for vertical loading and by 35–62% and 42.4–56.2% for lateral loading. The cortical bone thickness has a stronger correlation (R²=0.95–0.71) with ITV, PTV, and ISQ than the elastic modulus of trabecular bone (R²=0.89–0.59). Conclusions: The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the elastic modulus of trabecular bone; however, these parameters are not totally linearly correlated with ITV, PTV, and ISQ. The placement of an immediately loaded implant in cases with thin cortical bone and/or weak trabecular bone can induce extreme bone strains and may increase the risk of implant failure. To cite this article:
Huang H‐L, Chang Y‐Y, Lin D‐J, Li Y‐F, Chen K‐T, Hsu J‐T. Initial stability and bone strain evaluation of the immediately loaded dental implant: an in vitro model study.
Clin. Oral Impl. Res. 22 , 2011; 691–698
doi: 10.1111/j.1600‐0501.2010.01983.x