Influence of presence or absence of keratinized mucosa on the alveolar bony crest level as it relates to different buccal marginal bone thicknesses. An experimental study in dogs

A New Concept of Horizontal Bone Augmentation Using Collagen Bovine Bone Blocks Without Membrane at Implant Placement: A Preliminary Study

Purpose

A buccal bone thickness (BBT) of at least 1.8-2 mm is necessary to ensure long-term implant stability, and a bone grafting procedure is commonly needed to restore this BBT. This study aims to prove the effectiveness of a novel bone augmentation technique in which minero-organic bone substitutes are solely used to restore adequate BBT, excluding the need for coverage membranes.

Methods

Fifty partially edentulous patients having a residual bone width ranging between 5 and 6 mm were enrolled in this study. The horizontal buccal defects were grafted simultaneously at implant placement. Minero-organic collagen bovine bone blocks (CBBB) were placed on the outer side of the buccal bone wall, and adapted to the defect morphology through slow compressive movements. The grafted sites were not covered with any type of membrane nor stabilized with fixation pins. Cone-beam computed tomography scans were obtained pre-operatively, immediately post-surgery, and four months later. Scans were superimposed on the ITK-Snap software to measure the amount of bone gain and assess the percentage of CBBB resorption. Measurements were effectuated at four different levels apically to crestal level.

Results

Radiographic findings showed BBT increase and CBBB resorption in all cases, four months post-grafting. A mean horizontal bone gain of 1.39 mm was calculated at a crestal level.

Conclusion

Based on these findings, it appears that this novel and user-friendly bone grafting technique can achieve positive outcomes from both clinical and radiographic perspectives.

Is there an effective way to control pain perception after free gingival graft removal? A systematic review and meta-analysis

The literature describes multiple ways to stimulate wound healing to reduce the patient's perception of pain. This systematic review aimed to evaluate if methods that enhance wound healing can reduce the patient's perception of pain after free gingival graft removal from the palate region compared to natural healing. A systematic review protocol was written following the PRISMA checklist. Electronic searches of five databases were performed to identify randomized clinical trials (RCTs) that assessed the patient's perception of pain after the removal of a free gingival graft from the palate. The primary outcome was the visual analog scale (VAS) score assessing the patient's perception of pain 7 days after the free gingival graft removal from the palate region. Of the 1,622 potentially relevant articles retrieved from the electronic databases, 16 RCTs were selected for qualitative analysis, and of these, 6 RCTs were included in the meta-analysis. RCTs showed a significant VAS reduction associated with the use of methods to enhance wound healing. The pooled estimates revealed a significant overall VAS reduction of 2.20 (95% CI 2.32, 2.07) 7 days after surgery. The methods that presented the greatest reduction in the perception of pain were platelet-rich fibrin, hyaluronic acid, and autologous fibrin glue. Methods that enhance wound healing, including platelet-rich fibrin, hyaluronic acid, and autologous fibrin glue, can reduce pain perception after free gingival graft removal in the palate region. However, only 1 RCT investigated each approach, which hinders the conclusion regarding the best procedure to reduce the perception of pain.

Influence of buccal bone wall thickness on the peri-implant hard and soft tissue dimensional changes: A systematic review

BACKGROUND

The significance on the association between the peri-implant bucco-lingual dimension (BLD) at the stage of implant placement and the occurrence of biological and esthetic complications is yet unknown.

MATERIAL AND METHODS

Systematic screening of electronic sources was carried out to identify clinical and preclinical studies reporting on the baseline BLD and/or buccal bone thickness (BBT) values. A secondary objective was to assess the effect of simultaneous grafting at sites with deficient or no buccal bone wall (BBW) at baseline. The primary outcome variables were BBT, BLD, and buccal vertical bone loss (VBL) at re-evaluation. Moreover, radiographic, clinical, and patient-reported outcome measures (PROMs) were evaluated.

RESULTS

Overall, 12 clinical and four preclinical studies met the inclusion criteria. Inconsistencies were found in defining the critical BBT across the clinical and preclinical data evaluated. The clinical evidence demonstrated that during healing, dimensional changes occur in the alveolar bone and in the BBW that may compromise the integrity of the peri-implant bone, leading to VBL and mucosal recession (MR), particularly in scenarios exhibiting a thin BBW. The preclinical evidence validated the fact that implants placed in the presence of a thin BBW, are more prone to exhibit major dimensional changes and VBL. Moreover, the clinical data supported that, in scenarios where dehiscence-type defects occur and are left for spontaneous healing, greater VBL and MR together with the occurrence of biologic complications are expected. Furthermore, the augmentation of dehiscence-type defects is associated with hard and soft tissue stability. PROMs were not reported.

CONCLUSIONS

Dimensional changes occur as result of implant placement in healed ridges that may lead to instability of the peri-implant hard and soft tissues. Sites presenting a thin BBW are more prone to exhibit major changes that may compromise the integrity of the buccal bone and may lead to biologic and esthetic complications.

Significance of buccal bone wall thickness on the fate of peri-implant hard and soft tissues: A systematic review

BACKGROUND

The significance of the association between the peri-implant buccolingual dimension (BLD) at the stage of implant placement and the occurrence of biological and esthetic complications is yet unknown.

MATERIAL AND METHODS

Systematic screening of electronic sources was carried out to identify clinical and preclinical studies reporting on the baseline BLD and/or buccal bone thickness (BBT) values. A secondary objective was to assess the effect of simultaneous grafting at sites with deficient or no buccal bone wall (BBW) at baseline. The primary outcome variables were BBT, BLD, and vertical bone loss (VBL) at re-evaluation. Moreover, radiographic, clinical- and patient-reported outcome measures (PROMs) were evaluated.

RESULTS

Overall, 12 clinical and four preclinical studies met the inclusion criteria. The clinical evidence demonstrated that during healing, dimensional changes occur in the alveolar bone and in the BBW that may compromise the integrity of bone around a dental implant. The preclinical evidence validated the fact that implants placed in the presence of thin BBW are more prone to exhibit major dimensional changes. Moreover, the clinical and preclinical data supported that in scenarios where dehiscence-type defects are left for spontaneous healing, greater VBL and mucosal recession (MR) together with the occurrence of biologic complications are expected. Furthermore, the augmentation of dehiscence-type defects is associated with hard and soft tissue stability.

CONCLUSIONS

Dimensional changes occur as a result of implant placement in healed ridges that may lead to VBL and MR. Thin BBW (≲2 mm) are prone to exhibit major postchanges that may compromise the integrity of the buccal bone, biologic and esthetic complications.

Regeneration of keratinized tissue around teeth and implants following coronal repositioning of alveolar mucosa with and without a connective tissue graft: An experimental study in dogs: Fifty years after Karring's landmark study: Fifty years after Karring's 71 landmark study

AIM

To compare clinical and histological keratinized tissue formation around teeth and implants following coronal repositioning of alveolar mucosa with or without a connective tissue graft (CTG).

MATERIALS AND METHODS

In nine beagle dogs, the third and fourth premolars (P3 and P4) were extracted from one side of the maxilla. Three months after the tooth extraction, a full-thickness buccal flap was raised and two implants were placed in those healed areas. On the contra-lateral side, a buccal flap was also raised at the P3 and P4 areas. Before suturing, the dogs were randomly assigned to three study groups (control, non-keratinized tissue [NKT], and non-keratinized tissue CTG [NKT-CTG]). In the control group, the buccal flaps were re-positioned around the teeth (P3 and P4) on one side, and implants on the other side, presenting an adequate band of keratinized tissue (KT). For the NKT and NKT-CTG groups, this buccal KT was then excised. In the NKT group, the buccal flap without KT (alveolar mucosa) was re-positioned around the teeth and implants. In the NKT-CTG group, a CTG taken from the excised KT was sutured to the buccal alveolar mucosa and then both were re-positioned around the teeth and implants. The clinical height of the KT was measured at baseline and at 1, 2, and 3 months of healing. The animals were sacrificed at 3 months, at which point the KT height was measured histologically.

RESULTS

The control group presented normal healing with a band of KT surrounding the teeth and implants. In the NKT and NKT-CTG groups, a new KT band approximately 2 mm in height (measured clinically and histologically) spontaneously formed around all teeth, regardless of whether a CTG had been placed. In the NKT implant group, no new KT was observed (clinically or histologically). Around the implants in the NKT-CTG group, a small amount of KT was formed in just two of the six implants.

CONCLUSIONS

After surgical excision of KT, spontaneous KT is formed around teeth but not around implants, regardless of the placement of a CTG.

Dimensional Changes in Free Epithelialized Gingival/Mucosal Grafts at Tooth and Implant Sites: A Prospective Cohort Study

BACKGROUND

A study was made of the dimensional changes in free epithelialized gingival/mucosal grafts (FEGs) used to augment keratinized tissue (KT) at tooth and implant sites, and of the confounders influencing the dynamic changes over 6 months of follow-up.

MATERIAL AND METHODS

A prospective cohort interventional study was made of implant and tooth sites needing keratinized tissue augmentation by means of an apically positioned flap and FEG. Six intraoperative variables were recorded at baseline (T0). In addition, graft width (GW), graft length (GL) and graft dimension (GD) were assessed at three weeks (T1), three months (T2) and 6 months of follow-up (T3). Univariate and multivariate analyses were performed to explore associations between the demographic and intraoperative variables and the outcomes over the study period.

RESULTS

Based upon an a priori power sample size calculation, a total of 56 consecutive patients were recruited, of which 52 were available for assessment. A total of 73 graft units were included in 122 sites. At T3, the mean change in GD in FEG was 40.21%. In particular, the mean changes in GL and GW were 12.13% and 33.06%, respectively. Statistically significant changes in GD were recorded from T0 to T1 (p<0.0005) and from T1 to T2 (p<0.0005), but not from T2 to T3 (p = 0.13). The change in GD at T3 was 33.26% at tooth and 43.11% at implant site level (p = 0.01). Age and GW assessed at T0 proved to be related to the changes in GD and GW in the univariate and multivariate analyses. The univariate analysis showed the avascular area (AA) to be related to the changes in GD and GW at the implant sites, while graft thickness (GT) was associated to changes in GD and GW at the tooth sites in the univariate and multivariate analyses.

CONCLUSIONS

Free epithelialized grafts are exposed to dimensional changes that result in a reduction of approximately 40% of the original graft dimension - the changes being approximately 10% greater at the implant sites than at the tooth sites (NCT04410614). This article is protected by copyright. All rights reserved.

Horizontal Ridge Augmentation: A Comparison between Khoury and Urban Technique

PURPOSE

The objective of this systematic review was to evaluate and compare the clinical efficacy of horizontal alveolar ridge augmentation techniques described by Khoury and Urban.

METHODS

A systematic electronic search in the MEDLINE databases, SCOPUS, WOS, and the Cochrane Central Register of Controlled Trials (CENTRAL) as well as a manual search, were conducted independently by two reviewers up to July 2021.

RESULTS

Six studies met the pre-established inclusion criteria and were included in the descriptive analysis. Due to the heterogeneity found across the included studies, meta-analysis could not be performed. Horizontal bone gain was between 3.93 ± 0.9 mm and 5.02 ± 0.8 mm with the Khoury technique and between 3.9 ± 0.9 mm and 5.68 ± 1.42 mm with the Urban technique. Similar complication rates were reported in both groups: infection (7%), in the Khoury technique, and membrane exposure (3.2-13.6%), in the Urban technique, being the most frequent events.

CONCLUSIONS

Both techniques were found to be effective, in terms of clinical bone gain, for horizontal alveolar ridge gain. Nevertheless, available literature is limited, and there is a lack of comparative studies to better evaluate the results.

Analysis of Prosthetic Factors Affecting Peri-Implant Health: An in vivo Retrospective Study

Objective

To investigate and compare the various restorative and prosthetic parameters affecting peri-implant tissues’ health following dental implant placement and functional loading.

Methods

A total of 484 dental implants (length>6mm, non-turned, 2–3 piece, titanium – Straumann) were evaluated for patients (male=271; female=213). Study variables such as patient’s age, gender, implant restoration/crown type, crown retention, and implant crown status were assessed against various periodontal parameters (periodontal pocket depth (PPD), plaque index (PI), bleeding on probing (BOP), gingival color, and crestal bone level). All the data were analyzed using the SPSS software.

Results

Out of all the investigated dental implants, 201 (42%) of the implants investigated presented with BOP > one-site of the peri-implant mucosa (peri-implant mucositis), 115 (23.76%) presented with peri-implant marginal bone loss. PPD value was significantly lower in good crown status (p<0.0001). Majority of the patients with good crown status had no plaque accumulation based on the PI scores (52.7%). Only 35% of the patients whose crown status was good were having BOP when compared with 65% who did not have any BOP recorded. Gingival color (pale pink and red) showed statistically significant association with crown type (porcelain fused to metal v/s all ceramic) (p=0.005). Most of patients with crown status good had no change in their radiographic findings (94%) compared to only 6% who had implant threads exposed (p<0.0001).

Conclusion

Optimal design of Implant prosthetic factors are vital for avoiding the development of peri-implant mucositis/peri-implantitis and must be considered during treatment planning while restoring dental implants.

Evaluation of clinical performance and survival rate of Straumann dental implants in Saudi Population based on cross-sectional study

Risk indicators of peri-implantitis is still contradictory and somehow unclear in present literature therefore efforts should be done for better understanding of the exact etiology of peri-implant disease progression. The present study aimed to assess risk indicators associated with peri-implantitis by observing the changes in several periodontal parameters after implant placement. This cross-sectional study included 213 female and 271 male patients aged 26–87 years, who received 484 titanium implants (Straumann, Switzerland) at King Saud University’s Dental College, Saudi Arabia. Patients were called for dental visits. During these visits; full clinical and radiographic assessment of implants were done. The periodontal pocket depth (PPD) was greater around implants placed at grafted sites than non-grafted sites and around bone-level implants than tissue-level implants. The plaque index (PI) was associated with poor oral hygiene. There was a strong association between graft (yes/no) and bleeding on probing (BOP). Patients with good oral hygiene showed high radiographic bone stability. Keratinized tissue width < 2 mm was associated with a higher PPD, higher PI, higher BOP, more edematous gingiva, and more exposed implant threads on radiography. In patients receiving implants, poor oral hygiene status and inadequate keratinized tissue level can be proposed as risk indicators for developing periimplantitis due to strong association found between them and developments of peri-implantitis.

The biological width around implant

PURPOSE

The concept of biological width has been proposed and widely used in oral implantation. This review aimed to summarize the biological width around implant in detail.

STUDY SELECTION

An electronic search of the literature prior to March 2019 was performed to identify all articles related to biological width in periimplant soft tissue. The search was conducted in the MEDLINE (National Library of Medicine) database accessed through PubMed with no date restriction. The following main keywords were used: "implant", "biological width", "soft tissue", "junctional epithelium", "peri-implant epithelium", "connective tissue", "gingiva", "mucosa" (connecting multiple keywords with AND, OR).

RESULTS

The identified researches focused on several aspects related to biological width in oral implantation, namely the concept, formation, remodeling, dimension, structure and function.

CONCLUSIONS

Based on of the reviewed literature, the concept, formation, remodeling, structure, dimension, and functional significances of periimplant biological width are explored in this narrative review. The formation of biological width around implant is a complex process after several weeks of healing. The biological width around implant is a 3-4mm distance from the top of the peri-implant mucosa to the first bone-to-implant contact or the stabilized top of the adjacent bone, consisting of sulcular epithelium, junctional epithelium and fibrous connective tissue between the epithelium and the first bone-to-implant contact or the stabilized top of the adjacent bone. The biological width forms a biological barrier against the bacteria, influences the remodeling of soft and hard tissue around implant and has implications for clinical aspects of dental implantation.

Clinical outcomes and bone-level alterations around one-piece mini dental implants retaining mandibular overdentures: 5-year follow-up of a prospective cohort study

OBJECTIVES

To report on the clinical outcomes of one-piece mini dental implants (MDIs) retaining mandibular implant overdentures (IODs), including marginal bone-level alterations (ΔMBLs), clinical peri-implant parameters, and technical- and biological complications during a 5-year follow-up. The null hypothesis was that ΔMBLs would be equal in subjects older than 65 years relative to younger subjects.

MATERIALS AND METHODS

Four 1.8-mm diameter one-piece MDIs with ball attachments were placed in the interforaminal region of 20 edentulous subjects. The existing complete dentures were converted to IODs. Standardized radiographs of each implant were taken at implant placement (baseline) and during the five-year follow-up. ΔMBLs and potential influencing factors were evaluated, and peri-implant parameters, and biological and technical complications were recorded.

RESULTS

The implant and prosthetic survival rates were both 100%. IODs fractured in seven participants. The overall mean ΔMBL after 5 years was -1.18 mm (standard deviation: 0.79 mm). ΔMBLs per month were most pronounced within the first 3 months after implant placement. ΔMBLs were not influenced by the implant location, the presence of keratinized mucosa, or gender. However, ΔMBLs were significantly smaller in subjects older than 65 years (p = .007).

CONCLUSIONS

One-piece MDIs retaining mandibular IODs with O-ring attachments are a predictable treatment option, providing stable peri-implant bone and soft tissue conditions over a mid-term follow-up. Incorporating a metal reinforcement can prevent denture fracturing when converting a complete denture into an IOD. The presence of keratinized mucosa does not necessarily lead to decreased bone-level changes. Advanced age might be beneficial in terms of peri-implant bone stability.

Focus on Epithelialized Palatal Grafts. Part 2: Implant Site Development

INTRODUCTION

The epithelialized palatal graft (EPG), introduced in 1963, has persisted as the gold standard for gingival augmentation, and in the present era, mucosal augmentation around dental implants has become an important concern. A limited body of evidence suggests peri-implant mucosal augmentation may favorably impact bone and mucosal stability and peri-implant health under some circumstances. Although more contemporary procedures for peri-implant mucosal augmentation are often preferred based on convenience and esthetic considerations, EPG augmentation at dental implant sites is distinguishable from methods which do not deepen the vestibule and eliminate unfavorable superficial soft tissue. Implant sites augmented with EPG are qualitatively distinct from sites augmented using other methods.

CASE SERIES

Seven generally healthy patients received EPG augmentation before dental implant placement, at implant placement, before implant uncovering, or after implant uncovering. In each case, the patient exhibited a favorable zone of attached peri-implant mucosa following treatment.

CONCLUSIONS

Reliable mucosal augmentation with EPG is achievable at multiple phases in the course of dental implant therapy. EPG augmentation offers distinct clinical advantages and may be preferable to other mucosal augmentation strategies at some dental implant sites.

Osseous Remodeling Around Dental Implants

Adequate bone remodeling may be a primary parameter for long-term successful complication-free dental implant treatment. A 1.8-mm osseous thickness around dental implants is thought to be the minimum thickness for adequate vasculature for osteocyte nutrition and function. A dental implant does not provide progenitor cells or angiogenic or osteogenic factors. Thus, the surrounding bone may need to have a 1.8-mm thickness to accommodate the vasculature necessary for nutrients for appropriate remodeling. Additionally, the 1.8-mm dimension may provide for mechanical load resistance. There is no evidence to illustrate the physiologic need for the 1.8-mm dimension. This dimension requirement is based on clinical outcome observations. Basic science research for bone survival around dental implants is needed.

Peri-implant bone loss clinical and radiographic evaluation around rough neck and microthread implants: a 5-year study

OBJECTIVE

To evaluate marginal bone loss over 5 years around microthreaded implants placed in the maxillary anterior/esthetic zone and immediate restored with non-occlusal loading.

MATERIALS AND METHODS

Seventy-one implants (with microthreads up to the platform-rough surface body and neck, internal connection and platform switching) were placed in healed bone in the maxillary arches of 30 men and 23 women (mean age 37.85 ± 7.09 years, range 27-60). All subjects had at least 3 mm of soft tissue to allow the establishment of adequate biologic width and to reduce bone resorption. Each patient received a provisional restoration immediately after implant placement with slight occlusal contact. Mesial and distal bone height was evaluated using digital radiography on the day following implant placement (baseline) and after 1, 2, 3, 4 and 5 years. Primary stability was measured with resonance frequency analysis.

RESULTS

No implants failed, resulting in a cumulative survival rate of 100% after 3 years. Marginal bone loss from implant collar to bone crest measured at baseline (peri-implant bone defect at the fresh extraction socket) and after 5 years was 0.90 mm ± 0.26 mm. Mesial and distal site crestal bone loss ranged from 3.42 ± 1.2 mm at baseline to 3.51 ± 1.5 mm after 5 years and from 3.38 ± 0.9 mm at baseline to 3.49 ± 0.9 mm after 5 years, respectively (P = 0.086).

CONCLUSIONS

The results of this study showed limited implant crestal bone loss 0.90 mm ± 0.26 mm and 100% of implant survival rate at 5-year follow-up of immediate restored implants with rough surface neck and microthreads.

Experimental Analysis of Temperature Differences During Implant Site Preparation: Continuous Drilling Technique Versus Intermittent Drilling Technique

Implant site preparation through drilling procedures may cause bone thermonecrosis. The aim of this in vitro study was to evaluate, using a thermal probe, overheating at implant sites during osteotomies through 2 different drilling methods (continuous drilling technique versus intermittent drilling technique) using irrigation at different temperatures. Five implant sites 13 mm in length were performed on 16 blocks (fresh bovine ribs), for a total of 80 implant sites. The PT-100 thermal probe was positioned 5 mm from each site. Two physiological refrigerant solutions were used: one at 23.7°C and one at 6.0°C. Four experimental groups were considered: group A (continuous drilling with physiological solution at 23.7°C), group B (intermittent drilling with physiological solution at 23.7°C), group C (continuous drilling with physiological solution at 6.0°C), and group D (intermittent drilling with physiological solution at 6.0°C). The Wilcoxon rank-sum test (2-tailed) was used to compare groups. While there was no difference between group A and group B (W = 86; P = .45), statistically significant differences were observed between experimental groups A and C (W = 0; P =.0001), B and D (W = 45; P =.0005), and C and D (W = 41; P = .003). Implant site preparation did not affect the overheating of the bone. Statistically significant differences were found with the refrigerant solutions. Using both irrigating solutions, bone temperature did not exceed 47°C.

Quadruple zygomatic implants supported rehabilitation in failed maxillary bone reconstruction

Extreme atrophy of the jaws constitutes a challenge for maxillofacial surgeons. The technique involving Le Fort I osteotomy, bone grafting, and endosseous implants remains the gold standard treatment for class V and class VI atrophy of the maxilla. As severe maxillary atrophy is associated to impaired microvascularization of overlying soft tissues, reconstruction using vascularized free fibula flaps together with endosseous implants is one of the possible treatment plans. When this approach fails, however, retreating these patients using traditional techniques often proves unsatisfactory. This study outlines our clinical experience with full-arch zygoma implant-supported prosthetic rehabilitation to treat severe atrophic maxilla following failure of strategies including multiple Le Fort I procedures or vascularized free fibular flaps.

Are Zygomatic Implants Associated With Maxillary Sinusitis?

PURPOSE

The purpose of the present study was to analyze the relation between zygomatic implants and symptomatic and radiologic modifications of the maxillary sinuses.

MATERIALS AND METHODS

A retrospective cohort study of patients who underwent zygomatic implant rehabilitation at the Clinic of Dentistry and Maxillofacial Surgery of the University of Verona from January 2005 through May 2014 was designed. The primary predictor variable was time (pre- vs postoperative). Concerning outcome variables, radiologic findings of thickened mucosa or opacification of the maxillary sinuses were evaluated on computed tomograms using the Lund-Mackay Staging System. Clinical symptoms were evaluated using the Sino-Nasal Outcome Test-20 (SNOT-20). The parameters assessed underwent descriptive statistical analysis.

RESULTS

The sample was composed of 41 patients (mean age, 54 yr; 61% women). Preoperatively, 12% had sinus findings. Postoperatively, 46% had sinus findings (P = .0001 by McNemar paired test). Preoperatively, 12% had a SNOT-20 score higher than 11. Postoperatively, 15% had a SNOT-20 score higher than 11 (P = 1 by McNemar paired test).

CONCLUSIONS

In accordance with data in the literature data, placement of zygomatic implants does not seem to be associated with severe rhinosinusitis complications. However, in a considerable number of patients, asymptomatic radiologic alterations of the paranasal sinuses were observed. Therefore, it is important to plan assessments of the prosthetic and peri-implant components of the procedure and the postoperative homeostasis of the maxillary sinuses.

Soft-tissue grafting for peri-implantitis-a treatment option in case of unsuitable skeletal basic morphology of the alveolar bone and lack of keratinized mucosa: a retrospective clinical cohort study

BACKGROUND

This retrospective study evaluated soft-tissue grafting as a surgical treatment option for peri-implantitis in case of unsuitable basic skeletal morphology of the alveolar bone and lack of keratinized mucosa.

METHODS

Twenty-eight patients (21 females, 7 males, at a mean age 59.4 years) were included with a total of 54 implants. All implants showed peri-implantitis and attached keratinized buccal mucosa of ≤2 mm. A surgical procedure of soft-tissue grafting (STG) was made by inserting an inlay and inlay-onlay transplant. Clinical investigations were made prior to the STG (baseline) and after 9-180 months (Ø 43 months) including the following parameters: soft-tissue biotype, skeletal basic morphology of the alveolar bone, width of the peri-implant keratinized mucosa (KM), mobility of the KM, pocket probing depth (PPD), and bleeding on probing (BOP).

RESULTS

Nearly all patients showed a thin soft-tissue biotype. The analysis of the skeletal basic morphology of the alveolar bone revealed a narrow apical base in 18 patients, middle base in 7 patients, and broad base in 3 patients. Width of the KM increased significantly (p < 0.01) from 0.4 ± 0,5 mm to 4.3 ± 1.5 mm after STG and PPD was significantly (p < 0,01) reduced from 6.3 ± 2,3 mm to 4.1 ± 1.9 mm. A significant reduction (p < 0.01) in BOP was recorded. All patients reported a clinical improvement of the inflammatory symptoms at follow-up.

CONCLUSIONS

The results of this study showed that the STG can be applied successfully as a surgical treatment of peri-implantitis. It remains unclear whether soft-tissue biotype or the skeletal basic morphology of the alveolar bone affects the outcome of this surgical treatment.

The alveolar ridge splitting/expansion technique: a systematic review

PURPOSE

The aim of this systematic review was to evaluate clinical, radiological and histological outcomes of the alveolar ridge splitting/expansion technique (ARST) with or without GBR.

MATERIALS AND METHODS

A screening of two databases MEDLINE (PubMed) and EMBASE (OVID) and hand search of articles were performed. Human and animal studies reporting on dental implants placed with simultaneous ARST up to May 31st 2014 were considered. Quality assessment of selected full-text articles was performed according to the ARRIVE guidelines and the Cochrane collaboration's tool to assess risk of bias.

RESULTS

Overall, 18 human and six animal studies (risk of bias: high/unclear) were included in this review. No randomized controlled trials were found. Due to the heterogeneity of study designs, definitions of success criteria, outcome variables, observation times and surgical procedures, no meta-analysis was performed. Reported survival (18 studies) and success (nine studies) rates ranged from 91.7 to 100% and 88.2 to 100%, respectively, with a mean follow-up of 1-10 years. Crestal bone level changes (∆CBL) in some studies indicate slightly higher bone loss before and after loading. Histologic and histomorphometric data from six animal studies confirm the crestal bone loss, particularly at buccal sites.

CONCLUSIONS

Within the limitations of this review, ARST seems to be a well-functioning one-stage alternative to extended two-stage horizontal grafting procedures. Data indicate that during healing and first year of loading, increased ∆CBL particularly at buccal sites must be anticipated. Additional horizontal GBR can help to preserve buccal bone height and width.

Marginal bone and soft tissue behavior following platform switching abutment connection/disconnection--a dog model study

OBJECTIVE

The effect on the marginal peri-implant tissues following repeated platform switching abutment removal and subsequent reconnection was studied.

MATERIAL AND METHODS

Six adult female Beagle dogs were selected, and Pm3 and Pm4 teeth, both left and right sides, were extracted and the sites healed for 3 months. At this time, 24 bone level (BL) (Straumann, Basel, Switzerland) Ø 3.3/8 mm implants were placed, 2 in each side on Pm3 and Pm4 regions. In one side (control group), 12 bone level conical Ø 3.6 mm healing abutments and, on the other side (test group), 12 Narrow CrossFit (NC) multibase abutments (Straumann) , Basel, Switzerland) were connected at time of implant surgery. On test group, all prosthetic procedures were carried out direct to multibase abutment without disconnecting it, where in the control group, the multibase abutment was connected/disconnected five times (at 6/8/10/12/14 weeks) during prosthetic procedures. Twelve fixed metal bridges were delivered 14 weeks after implant placement. A cleaning/control appointment was scheduled 6 months after implant placement. The animals were sacrificed at 9 months of the study. Clinical parameters and peri-apical x-rays were registered in every visit. Histomorphometric analysis was carried out for the 24 implants. The distance from multibase abutment shoulder to the first bone implant contact (S-BIC) was defined as the primary histomorphometric parameter.

RESULTS

Wilcoxon comparison paired test (n = 6) found no statistically significant differences (buccal P = 0.917; Lingual P = 0.463) between test and control groups both lingually and buccally for S-BIC distance. Only Pm3 buccal aBE-BC (distance from the apical end of the barrier epithelium to the first bone implant contact) (P = 0.046) parameter presented statistically significant differences between test and control groups. Control group presented 0.57 mm more recession than test group, being this difference statistically significant between the two groups (P < 0.001).

CONCLUSION

It can be conclude, within the limits of this animal study, that the connection/disconnection of platform switching abutments during prosthetic phase of implant treatment does not induce bone marginal absorption. Furthermore, it may present a negative influence in the buccal connective tissue attachment that becomes shorter anyway preventing marginal hard tissue resorption, especially in thin biotypes.

Healing at implant sites prepared conventionally or by means of Sonosurgery ®. An experimental study in dogs

OBJECTIVE

To compare peri-implant tissue healing at implants installed in sites prepared with conventional drills or a sonic device.

MATERIAL AND METHODS

In six Beagle dogs, the mandibular premolars and first molars were extracted bilaterally. After 3 months, full-thickness muco-periosteal flaps were elevated and recipient sites were prepared in both sides of the mandible. In the right side (control), the osteotomies were prepared using conventional drills, while, at the left side (test), a sonic device (Sonosurgery(®)) was used. Two implants were installed in each side of the mandible. After 8 weeks of non-submerged healing, biopsies were harvested and ground sections prepared for histological evaluation.

RESULTS

The time consumed for the osteotomies at the test was more than double compared to the conventional control sites. No statistically significant differences were found for any of the histological variables evaluated for hard and soft tissue dimensions. Although not statistically significant, slightly higher mineralized bone-to-implant contact was found at the test (65.4%) compared to the control (58.1) sites.

CONCLUSIONS

Similar healing characteristics in osseointegration and marginal hard tissue remodeling resulted at implants installed into osteotomies prepared with conventional drills or with the sonic instrument (Sonosurgery(®)).