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.     

Implant design and intraosseous stability of immediately placed implants: a human cadaver study

Objective: The objective of this study was to explore effects of implant macrodesign and diameter on initial intraosseous stability and interface mechanical properties of immediately placed implants. Material and method: Mandibular premolars of four fresh‐frozen human cadavers were extracted. Ø 4.1/4.8 mm ITI® TE®, Ø 4.1 and 4.8 mm solid screw synOcta® ITI® implants were placed into freshly prepared extraction sockets. Resonance frequency analysis was conducted to quantify primary implant stability quotient (ISQ). Installation torque value (ITV) and removal torque value (RTV) of the implants were measured using a custom‐made strain‐gauged torque wrench connected to a data acquisition system at a sample rate of 10,000 Hz. The vertical defect depth around the collar of each implant was measured directly by an endodontic spreader. The bone–implant contact was determined in digitalized images of periapical radiographs and expressed as percentage bone contact. Results: The ISQ values of the TE® implant was higher than the Ø 4.1 mm implant (P<0.01), and comparable with the Ø 4.8 mm implants (P>0.05). ITVs and RTVs of TE® and Ø 4.8 mm implants were higher than the Ø 4.1 mm implant, although the differences between groups were statistically insignificant (P>0.05). The vertical defect depths around all types of implants were similar. In the radiographic analyses, percentage bone–implant contact of the TE® and Ø 4.8 mm implants were comparable at the marginal bone region and both were higher than that of the Ø 4.1 mm ITI® implant. Nonparametric correlations between groups revealed a significant correlation between ITV and RTV (r=0.838; P<0.001), but not between ISQ values and ITVs and RTVs (P>0.05). Conclusion: Immediately placed ITI® TE® implant leads to initial intraosseous stability and interface mechanical properties comparable with a wide diameter implant.     

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     

In Vitro Assessment of Primary Stability of Straumann® Implant Designs

Background: Primary implant stability (PS) is one of the main factors influencing implant survival rate. Several methods to determine the PS have been used, such as Periotest values (PVs) and resonance frequency analysis (RFA) with implant stability quotient (ISQ) values. Purpose: The aim of this study was to compare different implant designs in regard to PS assessed by Periotest and RFA in vitro. Materials and Methods: A total of 90 implants were placed in freshly slaughtered cow ribs. The implants (Straumann®, Institute Straumann AG, Basel, Switzerland; length 10 mm, ø3.3 mm) had the following three designs: Bone Level (BL, 30 implants), Standard Plus (SP, 30 implants), and Tapered Effect (TE, 30 implants). Before implant placement, the investigator was calibrated for every design according to the manufacturer's instructions. An independent observer, blinded to the study, assessed the accuracy of placement. RFA based on the Osstell device and PVs were performed after abutment connection. One‐way analysis of variance and Tukey's post hoc test were used for statistical evaluation. Results: All implants were mechanically stable. The mean PV for BL was ?4.67(± 1.18), for SP, ?6.07(± 0.94), and for TE, ?6.57(± 0.57). The mean ISQ values were 75.02(± 3.65), 75.98(± 3.00), and 79.83(± 1.85), respectively. The one‐way ANOVA showed significant difference among three implant designs in PV (p < .0001) and for the ISQ between BL/TE or SP/TE implants (p < .0001). In addition, the Tukey's (pair‐wise comparison) test showed significant differences in PV and RFA between the BL/TE (p < .0001). Conclusion: Within the limitations of this study, higher implant stability was found for tapered designed implants.     

Ridge alterations following immediate implant placement and the treatment of bone defects with Bio-Oss in an animal model

Background: Conflicting data exist on the outcome of placing Bio‐Oss® (Geitslich Pharm AG, Wolhausen, Switzerland) into extraction sockets. It is therefore relevant to study whether the incorporation of Bio‐Oss into extraction sockets would influence bone healing outcome at the extraction sites. Purpose: The aim of this study was to assess peri‐implant bone changes when implants were placed in fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles in a canine mandible model. Materials and Methods: Six mongrel dogs were used in the study. In one jaw quadrant of each animal, the fourth mandibular premolars were extracted with an elevation of the mucoperiosteal flap; implants were then placed in the fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles. After 4 months of healing, micro‐computed tomography at the implant sites was performed. Osseointegration was calculated as the percent of implant surface in contact with bone. Additionally, bone height was measured in the peri‐implant bone. Results: Average osseointegration was 28.5% (ranged between 14.8 and 34.2%). The mean crestal bone loss was 4.7 ± 2.1 mm on the buccal aspect, 0.4 ± 0.5 mm on the mesial aspect, 0.4 ± 0.3 mm on the distal aspect, and 0.3 ± 0.4 mm on the lingual aspect. Conclusion: The findings from this study demonstrated that the placement of implants and Bio‐Oss® particles into fresh extraction sockets resulted in significant buccal bone loss with low osseointegration.     

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     

Stereoscopic Technique for Conversion of Radiographic Guide into Implant Surgical Guide

Purpose: The aim of this study was to develop and evaluate a new stereoscopic technique for conversion of radiographic guide into surgical guide for dental implant placement. Materials and Methods: Ten partially dentate patients requiring 18 implants for tooth replacement were recruited. Radiographic guides were modified with the addition of index rods for double computed tomography scanning. Implant positions were planned with implant planning software, and the stereoscopic angulations were measured. The radiographic guides were converted into surgical guides using either a generic bench drill (Group A, n = 9) or a milling machine (Group B, n = 9). Stereolithographic surgical guides were also made for three patients (Group S, n = 5). Differences between the planned and actual angulations were tested by pair‐sample t‐test. Difference of mean angle deviation among groups was tested by Brown–Forsythe test. Differences were considered significant if p < .05. Results: Eighteen implant sites were successfully treated with the converted surgical guides. The mean angle deviation of Group A (1.3 ± 0.6°) was significantly greater than Group S (0.4 ± 0.6°), while no differences were found between Group B (0.9 ± 0.3°) and Group S. The linear error was greatest in Group A with 1.5 mm at the head and 1.8 mm at the apex of the implant. Conclusions: The use of this new stereoscopic technique appears to be an acceptable alternative method for converting radiographic guide into surgical guide.     

Influence of Thread Design on Implant Positioning in Immediate Implant Placement

Background: It is generally believed that implants placed in extraction sockets have a tendency to shift in the facial direction during insertion. The purpose of this study is to investigate the effect of different thread designs on the final implant position in immediate implant placement. Methods: In a split‐mouth design involving 11 cadaver heads, each specimen received two implants, one with a square and one with a V‐shaped thread design, in maxillary incisor extraction sockets. The facio‐lingual locations of the drills and the implant were tracked, and the displacements were compared between the two groups. Results: No statistically significant differences were observed between the square and V‐shaped thread design groups. The mean displacements of the different groups showed a general tendency of the implants to be positioned facially compared with the initial drill trajectory. This tendency was greater for implants with square thread design. Conclusion: There was no significant effect of implant thread design on the positioning of implants in extraction sockets.     

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     

Influence of placement depth on bone remodeling around tapered internal connection implant: a clinical and radiographic study in dogs

Background: The aim of this study is to evaluate the influence of placement depth on bone remodeling around implants with two different types of tapered internal implant–abutment interface (IAI): tapped‐in (TI) tapered internal IAI and screwed‐in (SI) tapered internal IAI in dogs. Methods: The second, third, and fourth premolars and the first molar in mandibles of six beagle dogs were extracted. After 8 weeks, two SI implants and two TI implants were placed in one side of the mandible. There were four experimental groups: 1) SI placed crestally (SIC); 2) TI placed crestally (TIC); 3) SI placed 1.5 mm subcrestally (SIS); and 4) TI placed 1.5 mm subcrestally (TIS). Healing abutments were connected 12 weeks after implant surgery. Implants and teeth were brushed every second day during the healing period. Clinical and radiographic parameters were recorded at 4, 10, and 16 weeks after second‐stage surgery. Results: Differences between SI and TI implants inserted in the same vertical position were not significant for peri‐implant probing depth (PD), clinical attachment level (CAL), or bone resorption (P >0.05). Subcrestal placement of both implants had greater PD and CAL compared to crestal groups. However, distance from IAI to the first bone–implant contact was lower in subcrestal groups compared to crestal groups (1.27 ± 0.42 mm for SIC versus 0.46 ± 0.26 mm for SIS, P <0.05; 1.36 ± 0.31 mm for TIC versus 0.78 ± 0.42 mm for TIS, P <0.05). Conclusions: Tapered internal IAI configuration had no significant effect on crestal bone resorption. Moreover, subcrestal placement of tapered internal IAI had a positive impact on crestal bone preservation around the cervix of the implant.     

Flapless Implant Surgery Using a Mini‐Incision

Background: Traditional flapless implant surgery using a soft tissue punch device requires a circumferential excision of keratinized tissue at the implant site. A new flapless implant technique that can submerge implant fixtures is needed. Purpose: This article describes a flapless implant surgery method using a mini‐incision and compares the effects of soft tissue punch and mini‐incision surgery on both the amount of osseointegration and the bone height around the implants using a canine mandible model. Materials and Methods: Bilateral, edentulated, flat alveolar ridges were created in the mandibles of six mongrel dogs. After a 3‐month healing period, two implants were placed on each side of the mandible using either soft tissue punch or mini‐incision procedures. After an additional 3‐month healing period, a second stage surgery and transmucosal abutment attachment was performed for mini‐incision implant cases. Following a 2‐month healing period, the dogs were sacrificed to evaluate the osseointegration and bone height around the implants. Results: Average bone height was 9.6 ± 0.4 mm in the soft tissue punch group and 9.8 ± 0.3 mm in the mini‐incision group (p > .05). Average osseointegration was 70.4 ± 6.3% in the soft tissue punch group and 71.2 ± 7.1% in the mini‐incision group (p > .05). No significant differences were noted between the two groups in vertical alveolar ridge height or bone/implant contact. Conclusions: Our findings support the clinical use of mini‐incision implant surgery at sites where implants need to be protected below the soft tissue during the early phase of healing, particularly for patients with poor bone quality and/or low primary implant stability.     

Immediate vs. early loading of dental implants: 3‐year results of a randomized controlled clinical trial

Objectives: The aim of the present study was to test whether or not immediately loaded implants exhibit the same survival rates as early loaded implants. Material and methods: Eleven patients with bilateral free end mandibles were randomly assigned to treatment either with immediately (test) or early loaded implants (control). Test implants received provisionals in occlusion on the day of surgery, control implants 6 weeks later. Parameters assessed included implant stability quotient (ISQ), plaque, prosthesis stability and radiographs at baseline (implant insertion), 1 and 3 years. The statistical analysis was performed by means of Student's paired t‐test and Wilcoxon's signed‐rank test. The level of significance was set at P<0.05. Results: After a mean observation period of 39.8 months (36.7–53.1), three test implants were lost in two patients resulting in a survival rate of 85% compared with 100% for control implants. At baseline, the mean marginal bone level was significantly higher at test implants (mean=0.36 mm, SD ±0.5) compared with control implants (1.08±0.37 mm). For both test and control implants, the bone level significantly decreased from baseline to 3 years (test: 1.51±0.79 mm; control: 0.89±0.94 mm). The bone loss until 3 years was not significantly different between test and control group. There was no significant difference for ISQ both at test and control implants between baseline (test: 63.59±4.62 mm, control: 65.35±7.43 mm) and 3 years (test: 66.47±7.47 mm, control 68.80±8.75 mm). Conclusions: Immediate loading was associated with a lower implant survival rate. Although the test implants were placed with increased sink depth compared with the control implants, the marginal bone levels were not different between test and control at 3 years. To cite this article:
Zembi? A, Glauser R, Khraisat A, Hämmerle CHF. Immediate vs. early loading of dental implants: 3‐year results of a randomized controlled clinical trial.
Clin. Oral Impl. Res. 21 , 2010; 481–489.
doi: 10.1111/j.1600‐0501.2009.01898.x     

Effects of Implant Design and Surface on Bone Regeneration and Implant Stability: An Experimental Study in the Dog Mandible

Background: Previous experimental studies have shown a higher degree of bone‐implant contact for surface‐enlarged implants compared with machined implants. Yet, there is insufficient evidence that such implants show higher stability and an increased survival rate. Purpose: The purpose of this investigation was to study the integration and stability of grit‐blasted implants with retention elements on the implant neck, with and without marginal bone defects, compared with machined implants without retention elements. Materials and Methods: After tooth extraction of the mandibular premolars in six dogs, two grit‐blasted, partly microthreaded Astra Tech implants and one standard Branemark implant were bilaterally placed in each dog. On one side, 3 ± 3 mm large buccal defects were created, to expose three to four implant threads. The contralateral side served as control, and no defects were made. The animals were sacrificed after 4 months of healing. Implant stability was measured using resonance frequency analysis at implant installation and after 4 months of healing. Histologic and histomorpho‐metric evaluation was made after 4 months of healing. Results: Resonance frequency analysis indicated that all implants in the test and control groups were osseointegrated after 4 months, with a tendency toward higher implant stability for the Astra Tech implants. There was a statistically significant higher increase in resonance frequency for the Astra test implants compared with their corresponding controls. Histology and histomorphometry showed well‐integrated implants with varying degrees of bone repair at the defect sites. The greater bone‐implant contact for the Astra implants was statistically significant. No significant difference between the implants in amount of bone filling the threads was recorded. Conclusions: The Astra Tech implants tested showed a higher degree of bone—implant contact and higher level of bone regenerated at defect sites compared with the Brånemark implants. Resonance frequency analysis demonstrated a significantly higher increase in the Astra test implants compared with their control groups than did the Brånemark test implants versus their controls.     

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.     

Immediate Implant Placement in Infected Sites: A Case Series

Background: Immediate implant placement has several advantages, such as reduction in the number of surgical treatments and reduction of the time between tooth extraction and the placement of the definitive prosthesis. However, there are still some situations that could jeopardize the success of the aforesaid therapy, such as the presence of an infection caused by periodontal disease or periapical lesions. The aim of this case series is to evaluate the clinical success of implants placed in fresh extraction sockets that showed clinical signs of periodontal disease. Methods: Thirteen patients (six males and seven females, 24 to 65 years old) are included in this case series. After initial examination and treatment planning, all patients underwent the periodontal treatment deemed necessary to facilitate wound healing. Twenty teeth were extracted as a result of an infection. Second‐stage surgery was performed 4 months after the initial procedure. The following clinical parameters were evaluated for each patient at the time of implant placement and at the end of the 12‐month follow‐up period: 1) clinical attachment level (CAL); 2) presence or absence of mobility; 3) presence or absence of pain; and 4) presence or absence of suppuration. The bone level was measured as the distance from the implant shoulder to the first bone–implant contact (distance bone–implant [DIB]) by periapical radiographs. The stability and health of the soft tissue were clinically evaluated by means of the plaque score. Results: The healing period was uneventful for all the patients. All the implants were osseointegrated. At the end of the 12‐month follow‐up period, patients were asymptomatic and showed no signs of infection or bleeding when probed. The mean CAL at the mid‐buccal location per implant was 0.8 mm at baseline and 0.9 mm at the end of the follow‐up. The mean width of keratinized mucosa measured at the mid‐buccal location per implant at baseline and 1‐year visits was 3.2 ± 0.4 mm and 3.3 ± 0.5 mm, respectively. The periapical radiographs, obtained in a standardized manner, revealed a mean increase of 0.5 mm in the DIB value. At the 12‐month follow‐up, the presence of plaque was observed in 44 of the 80 sites analyzed. Conclusion: Based on the results of this case series, placement of implants in fresh extraction sockets affected by infection may be a valid operative technique that leads to predictable results if adequate preoperative and postoperative care is taken.     

Extraction socket preservation graft before implant placement with calcium sulfate hemihydrate and platelet-rich plasma: a clinical and histomorphometric study in humans

Background: The aim of this investigation is to evaluate clinical and histologic outcome of using medical‐grade calcium sulfate hemihydrate (MGCSH) mixed with platelet‐rich plasma (PRP) for extraction socket preservation graft before implant placement. Methods: This study is a single‐site, randomized and controlled investigation. Sixteen patients with a non‐restorable tooth requiring extraction followed by implant placement were enrolled in this study. After extraction of a tooth, eight selected patients randomly received MGCSH mixed with PRP in the extraction sockets (test group), and eight selected patients randomly received collagen resorbable plug dressing material (control group). At the time of extraction and 3 months later (at implant placement surgery), vertical and horizontal socket dimensions were measured. Bone core samples were retrieved from the center of the healed socket before implant placement for histomorphometric analysis. Results: There was a statistically significant difference between the two groups based on histomorphometric analysis (P <0.05). New vital bone percentage regenerated after 3 months of healing was 66.5% ± 10.4% in sockets grafted with MGCSH mixed with PRP compared to 38.3% ± 9.3% collagen resorbable plug. There was no statistically significant difference in the amount of vertical and horizontal bone resorption (P >0.05) between groups. In all cases but two in the control group, implants were placed with primary stability. Conclusion: MGCSH mixed with PRP showed greater vital bone volume at 3 months with rapid enhancement of bone healing compared to PRP‐free collagen resorbable graft.     

Bone‐to‐Implant Contact Around Immediately Loaded Direct Laser Metal‐Forming Transitional Implants in Human Posterior Maxilla

Objective: Direct laser metal forming (DLMF) is a procedure in which a high‐power laser beam is directed onto a metal powder bed and programmed to fuse particles according to a computer‐aided design file, generating a thin metal layer. This histologic study evaluated the bone‐to‐implant contact (BIC%) around immediately loaded DLMF transitional implants retrieved after 2 months from posterior human maxillae. Methods: Twelve totally edentulous individuals (mean age, 66.14 ± 2.11 years) received DLMF transitional implants divided in twelve immediately loaded (IL) and twelve unloaded (UI) implants. These transitional implants were placed between conventional implants to support the interim complete maxillary denture during the healing period. After 8 weeks, the transitional implants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results: Mature woven preexisting bone lined by newly formed bone in early stages of maturation were found around all retrieved implants. Histometric evaluation indicated that the mean BIC% was 45.20 ± 7.68% and 34.10 ± 7.85% for IL and UI, respectively (P <0.05). Conclusion: The present data obtained in humans showed that, although both IL and UI presented good BIC%, IL DLMF implants had a higher BIC% in the posterior maxilla.     

Histological and histomorphometric evaluation of immediate implant placement on a dog model with a new implant surface treatment

Purpose: The aim of this study was to evaluate crestal bone resorption and bone apposition resulting from immediate post‐extraction implants in the canine mandible, comparing a conditioned sandblasted acid‐etched implant surface with a non‐conditioned standard sandblasted implant surface. Material and methods: In this experimental study, third and fourth premolars and distal roots of first molars were extracted bilaterally from six Beagle dog mandibles. Each side of the mandible received three assigned dental implants, with the conditioned surface (CS) on the right side and the non‐conditioned surface (NCS) on the left. The dogs were sacrificed at 2 (n=2), 4 (n=2) and 12 weeks (n=2) after implant placement. Results: The microscopic healing patterns at 2, 4 and 12 weeks for both implant types (CS and NCS) yielded similar qualitative bone findings. The mean crestal bone resorption was found to be greater for all implants with NCS (2.28±1.9 mm) than CS (1.21±1.05 mm) at 12 weeks. The mean percentage of newly formed bone in contact with implants was greater in implants CS (44.67±0.19%) than with the NCS (36,6±0.11%). There was less bone resorption with the CS than the NCS. Conclusion: The data show significantly more bone apposition (8% more) and less crestal bone resorption (1.07 mm) with the CS than with the NCS after 12 weeks of healing. This CS can reduce the healing period and increase bone apposition in immediate implant placements. To cite this article:
Calvo‐Guirado JL, Ortiz‐Ruiz AJ, Negri B, López‐Marí L, Rodriguez‐Barba C, Schlottig F. Histological and histomorphometric evaluation of immediate implant placement on a dog model with a new implant surface treatment.
Clin. Oral Impl. Res. 21 , 2010; 308–315.
doi: 10.1111/j.1600‐0501.2009.01841.x     

A Retrospective,Multicenter Study on a Novo Wide‐Body Implant for Posterior Regions

Background: Wide implants are recommended as “rescues” after failure to increase primary stability in extraction sockets or in poor quality bone. Consequently, inferior results compared with regular diameter implants have been reported. Purpose: The purpose of this study was to evaluate retrospectively the outcome of a novo wide‐body implant (Max® implant, Southern Implants®, Irene, South Africa) designed for placement in the posterior regions. Materials and Methods: In four private practices, patients with at least one Max implant were examined by two independent examiners to determine implant survival and marginal bone loss. Surgical, prosthetic, and patient‐related parameters were evaluated to determine their influence on the treatment outcome. Results: Seventy‐five patients (31 male, 44 female), with a mean age of 58 years, received 93 Max implants (59 maxilla, 34 mandible) of 8 to 10 mm width. Twenty‐seven implants in molar extraction sockets and two in mature bone were immediately loaded; 42 in extraction sockets and 22 in mature bone were delayed loaded. The mean follow‐up was 14 months (6–34), and four implants failed (4.3%); mean bone loss after 1 year was 0.46 mm (SD 1.08; range ?5.45–3.25). A total of 91.4% lost <1.5 mm of bone during the first year. The implant survival rate was 89.7% and 98.4%, respectively, for the immediate and delayed loaded implants and 95.8% and 95.7% for delayed and immediate placement. Time of placement, time of loading, surgical protocol, or prosthetic design did not affect the outcome. Conclusion: Within the limitations of the study, the Max implant demonstrated a survival rate of 95.7% and stable bone conditions after a year, irrespective of loading or surgical protocol. Future prospective studies are needed to evaluate the soft and hard tissue changes in time.