April 13, 2018
Submerged, transmucosal healing show similar results in bone-level implants
Bone-level implants with submerged or transmucosal healing protocols showed similar outcomes after 5 years when bone-level implants were placed in nonmolar positions for single tooth replacement. The findings are from a study published in the January issue of Journal of Clinical Periodontology.
Researchers designed the 5-year clinical trial to measure radiographic and patient-related outcomes of single-tooth implant restorations using bone-level implants placed in the anterior maxilla following either a submerged or transmucosal surgical protocol.
Patients in the study were partly a subset sample of 40 patients from a multicenter clinical trial. Researchers placed Straumann Bone Level Implants that were 4.1 millimeters or 3.3 mm in diameter and 8, 10, 12, or 14 mm in length according to the manufacturer’s recommendation.
The researchers placed the implant shoulder level with the bone crest at least 1.5 mm from the adjacent natural teeth. Patients randomized to the transmucosal group received a transmucosal healing abutment, while those randomized to the submerged group received a flat screw cap, and implant heads were covered with the flaps and sutured.
Radiographs obtained right after implant placement were considered baseline. Bone level was defined as the distance from the implant shoulder to the first clearly visible bone-to-implant contact. Researchers chose the linear measurement with the most apical extension. They used the mean of the mesial and distal bone level for analysis.
Authors took clinical measurements at 6 sites per implant using a periodontal probe. The presence of papilla in the mesial and distal aspect of each implant was used to evaluate the esthetic outcomes and expressed according to the papilla index.
A total of 30 patients completed the 5-year follow-up visit. Most of the implants (90%) used were 4.1 mm in diameter. Authors found interproximal defects at the time of implant placement in 8 cases. Another 7 implants (4 in the submerged group, 3 in the transmucosal group) needed simultaneous regenerative procedures using a deproteinized bovine bone mineral and a noncrossed linked collagen membrane to treat small bone defects. The implant survival rate was 100% at the 5-year mark.
Mean (standard deviation [SD]) radiographic bone loss 5 years after implant placement was 0.59 (0.92) mm and 0.78 (1.03) mm for the submerged and the transmucosal groups, respectively. The mean papilla index score changed at the mesial and distal aspects in the submerged group from 0.67 to 2.00 and from 0.33 to 1.40, respectively. In the transmucosal group, the corresponding changes were 0.33 to1.73 and 0.33 to 1.00, respectively. None of these parameters reached statistical significance owing to a high SD among the measured values. The authors observed that statistical significance could be achieved by having a bigger sample size in each group.
The percentage of sites with an index greater than 1 grew from a 1.3% at baseline to 40.3% at the 5-year evaluation. This signified an increasing papilla fill over the 5-year duration of the study in both groups. After placement of the final restoration, 88.9% of the patients (16 of 18 in each group) rated as satisfied or very satisfied the 4 aspects evaluated (comfort, appearance, masticatory function and overall satisfaction). At the 5-year evaluation, this percentage increased to 93.3% (14 of 15 in each group). There was no patient unsatisfied for any of the questions assayed. In both groups, the best-rated aspect was the comfort.
Read the original article here.
Consulting Editor: Tapan Koticha, BDS
Diplomate, American Board of Periodontology
Director, Graduate Periodontics
University of Oklahoma Health Sciences Center, College of Dentistry
Adapting the vertical position of implants to prevent peri-implant bone loss
Soft-tissue thickness affects initial bone remodeling. Adapting the vertical position of the implant to the soft-tissue thickness may avoid unforeseen peri-implant bone loss. The findings are from a study published online February 23 in Journal of Clinical Periodontology.
Authors designed the study with 2 goals: to evaluate the effect of soft-tissue thickness on bone remodeling and to see if implant surface exposure could be avoided by adapting the vertical implant position in relation to the soft-tissue thickness.
Authors placed 50 implants in 25 completely edentulous mandibular arches (12 men and 13 women; mean age, 65 (9.09) years; range, 43-82). Each patient received 2 implants. Authors installed 1 implant equicrestally (control) according to the manufacturer’s guidelines. They adapted the vertical position of the second implant to the soft-tissue thickness (test), allowing at least 3 millimeters of space for biological width establishment.
Authors applied a systematic nonrandom assignment to determine the position of test and control implants.
Authors placed implants in 20 patients with a 1-stage procedure. They submerged implants for 3 months in 5 other patients owing to a lack of primary stability.
All implants were connected with a prosthesis and functionally loaded 3 to 4 months after implant placement using the Locator System. Bone levels were determined as the distance from a reference point, which corresponds with the lower edge of the smooth implant bevel at the implant abutment interface to the most crestal bone-to-implant contact point.
Authors analyzed correlations between soft-tissue thickness and initial bone level changes using the intra class correlation coefficient (ICC). Longitudinal bone level changes and differences in bone levels between test and control implants at 6, 12, and 24 months were analyzed using the Wilcoxon signed ranks test. Intersubject differences between submerged and nonsubmerged implants for test and control implants were analyzed using the Mann-Whitney U test.
Authors measured a mean (SD) initial soft-tissue thickness of 1.93 (0.60) mm (n = 24; range, 1.00-3.00) and 1.98 (0.65) mm (n = 24; range, 0.67-3.40) before implant placement, using bone sounding and ultrasonic measurements, respectively.
No implants failed at follow-up, for a 100% survival rate. Authors noted a significant correlation between initial soft-tissue thickness and bone level alterations after 6 months using ultrasonography (ICC, 0.610) and bone sounding (ICC, 0.641), with greater crestal bone loss for equicrestal implants when thin tissues were present. After 6, 12, and 24 months, implants in the control group showed a mean (SD) bone level of 0.72 (0.75) mm (n = 24; range, 0.00-2.45), 0.78 (0.81) mm (n = 24; range, 0.00-2.92), and 0.73 (0.72) mm (n = 24; range, 0.00-2,61), respectively, compared with a mean (SD) bone level of 0.04 (0.11) mm (n = 24; range, 0.00-0.45), 0.03 (0.10) mm (n = 24; range, 0.00-0.36), and 0.04 (0.10) mm (n = 24; range, 0.00-0.30) for the test implants. These differences were statistically significant.
Read the original article here.
Meet us in Vancouver for the 104th AAP Annual Meeting
With 45 continuing education courses and a special keynote presentation by retired Space Shuttle Commander Captain Mark Kelly, the AAP’s 104th Annual Meeting is one you won’t want to miss. Advance registration is now open. For more information, visit perio.org/meetings or e-mail firstname.lastname@example.org.
Connective tissue grafting in single immediately placed implant sites for less midbuccal mucosa recession studied
The combination of connective tissue grafting in single, immediately placed, and provisional implants leads to less mid-buccal mucosa recession regardless of gingival biotype. This finding is from a study published in the February issue of Journal of Clinical Periodontology.
Authors designed the randomized controlled study to test whether applying a connected tissue graft (CTG) results in less midbuccal mucosa recession in immediate implants when followed over 12 months.
Sixty patients with a failing tooth received an immediately placed and provisional implant. Patients randomly received either a CTG from the maxillary tuberosity (n = 30, test group) or no graft (n = 30, control group).
After implant placement, the authors harvested a split-thickness CTG from the maxillary tuberosity region. The CTG was placed in a supraperiosteal envelope flap prepared at the buccal aspect without using vertical incisions. The CTG was secured with vertical and horizontal mattresses.
The same day as implant placement, the healing abutment was removed and the screw-retained provisional crown was fitted directly onto the implant with 20 newton centimeters and adjusted to free it from centric contacts with antagonist teeth.
Authors measured the change in midbuccal mucosal level (MBML) 1 (T1) and 12 months (T12) after placement of the final implant crown. They compared this with baseline mucosal levels of the failing tooth (T0) as measured on standardized intraoral photographs.
At T12, no implants displayed marginal bone loss exceeding 1 millimeter, resulting in a success rate of 96.7% for both groups. Also at T12, average (standard deviation [SD]) MBML loss significantly differed between the control group (−0.5 [1.1] mm) and test group (0.1 [0.8] mm; P = .03;). In both groups, the changes in MBML between T1 and T12, were negligible (P = .74). Interroximal mucosal levels at T12 for both sides of the implant were comparable for the control and test groups.
The average (SD) loss of marginal bone between T1 and T12 was 0.06 (0.42) mm and 0.04 (0.46) mm on the mesial side in the control and test groups, respectively. Distal sides of the control and test groups gained, on average (SD), 0.03 (0.38) mm and 0.02 (0.37) mm, respectively. The intergroup results were comparable (control group: P = .49; test group: P = .96).
At T12, using the modified sulcus bleeding index authors noted no signs of gingival inflammation (score 0) in 100% and 93% of the patients in the control and test groups, respectively. Two patients in the test group had mild inflammation (score 1). At T12, 1 patient in the test group had no keratinized mucosa at the buccal side of the implant (score 0 on a scale ranging from < 1 mm of keratinized mucosa to ≥ 2 mm of keratinized mucosa), and 1 patient had a keratinized mucosa with a width of 1 to 2 mm (score 2). All other patients had a keratinized mucosa of 2 mm or greater (score 3).
Regression analysis revealed that connective tissue grafting leads to a gain in MBML between T0 and T12 (regression coefficient, 0.57; P = .03). The corrected analysis on including gingival biotype (P = .91) and height of the bone defect (P = .71) showed that both factors had no influence on the MBML as concluded from a negligible change of the regression coefficient to 0.54 (P = .06).
Considering the short follow-up duration in this study, it would be interesting to see if the marginally superior results of the test group are maintained over a longer period, authors said in discussion.
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Effect of incision design on interproximal bone loss of teeth adjacent to single implants
Both conventional and papilla-sparing incision designs used to place interdental single implants resulted in minimal bone loss at the interproximal aspect of adjacent teeth, according to a study published online February 16 in Clinical Oral Implants Research.
Authors designed the controlled randomized clinical trial with a 2-fold purpose: to measure the effect of intrasulcular and paramarginal incisions in implant surgery on interproximal bone loss of posterior teeth adjacent to interdental single implants and to assess the influence of the incision technique on peri-implant bone remodeling.
All 60 patients in the study underwent a supragingival scaling 3 weeks before the implant surgery. Authors divided patients in into 2 groups; 30 received an intrasulcular incision and 30 received a paramarginal incision. The intrasulcular incision was made in the attached mucosa of the edentulous area including the sulcus of the adjacent teeth, without release incisions. The paramarginal incision was made in the attached mucosa of the edentulous area without reaching the interproximal soft tissue surrounding the adjacent teeth and making 2 release incisions. The distance from the mid-crestal incision to the interproximal aspect of the adjacent teeth was roughly 1.5 to 2.0 millimeters.
After the incision was made, a full-thickness mucoperiosteal flap was raised. Authors placed an implant platform 1.0 to 1.5 mm subcrestally. They used a nonsubmerged approach. The flap was repositioned and sutured around the healing abutments. Authors removed sutures 1 week after surgery. They inserted and loaded screw-retained porcelain restorations after a 12-week healing period. Patients were monitored for 1 year after implant loading.
Authors obtained radiographs at baseline, at abutment connection (3 months postoperative), and 6 and 12 months after loading. Authors detected 2 reference points at the interproximal aspect of the adjacent teeth in the postoperative radiograph to measure interproximal bone loss: the cementoenamel junction and the most coronal aspect of the bone crest. They traced a straight line along the root from point A to B. This distance was considered the baseline.
After implant placement, the mean (standard deviation [SD]) bone position with respect to the cementoenamel junction was 2.34 (1.10; 95% confidence interval [CI], 1.93 to 2.75) mm in the intrasulcular group and 2.66 (1.03; 95% CI, 2.33 to 2.98) mm in the paramarginal group. After a 12-month follow-up, the mean (SD) bone position was 2.43 (0.97; 95% CI, 2.07 to 2.79) mm in the intrasulcular group and 2.76 (1.03; 95% CI, 2.37 to 3.14) mm in the paramarginal group. The mean bone reduction from baseline to 1-year follow-up was 0.09 (95% CI, –0.14 to 0.32) mm in the intrasulcular group and 0.10 (95% CI, –0.10 to 0.29) mm in the paramarginal group.
After the 12-month follow-up, mean (SD) peri-implant bone remodeling was 0.17 (0.34; 95% CI, –0.04 to 0.32) mm in the intrasulcular group and 0.15 (0.32; 95% CI, –0.03 to 0.28] mm in the paramarginal group. The frequency analysis showed 21 and 19 implants in the intrasulcular and in the paramarginal incisions, respectively, with no rough implant surface exposed.
“The appropriate flap design depends on the treatment goals of the individual surgical intervention and is based on patient, site and even surgeon-specific criteria,” the authors concluded. “Specific surgical requirements such as flap advancement after bone augmentation may dictate the incision lines and help the surgeon to choose the most suitable approach.”
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AAP publishes proceedings from best evidence consensus meeting on CBCT
The American Academy of Periodontology (AAP) recently published its first-ever “best evidence consensus” (BEC) proceedings on the topic of cone-beam computed tomography (CBCT). The proceedings are the result of the AAP’s inaugural BEC meeting, a model of scientific inquiry rooted in the best available published research and expert opinion.
The panel of more than 10 periodontists who participated in the BEC meeting determined that CBCT has diverse applications for both dental implant therapy and periodontal-orthodontic therapy and should be used when the benefit to the patient outweighs the risk. The use of CBCT in dental implant and periodontal-orthodontic cases can not only assist in planning a safer approach to treatment, but also facilitate interdisciplinary communication. For patients with periodontitis, 2D full-mouth radiographs combined with clinical probing remain the gold standard; however, CBCT may be beneficial in certain advanced cases. Click here to read the report in the Journal of Periodontology.
AAP and European Federation of Periodontology host world workshop on the classification of periodontal and peri-implant diseases and conditions
More than 100 international researchers, educators, and clinicians gathered in Chicago to review the latest literature and come to consensus on up-to-date guidelines for periodontal and peri-implant disease diagnosis and definition. Participants at the event deliberated diagnostic considerations for many topic areas, including peri-implant disease and conditions—a first, accommodating for what scientists and practitioners have come to understand about implant dentistry.
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Available for download: clinical and scientific papers from the AAP
The American Academy of Periodontology has developed a suite of resources to be used as guidelines for dentists dealing with periodontal health issues. These resources include disease classifications, AAP-commissioned reviews, parameters of care, position papers, consensus papers/clinical recommendations, and Academy statements. View and download these materials by clicking here.
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