Soft tissue grafting to improve the attached mucosa at dental implants: A review of the literature and proposal of a decision tree

Long-term evaluation of combined prosthetic-surgical approach and soft tissue augmentation in the esthetic zone

Background

There is no standard protocol for immediate implant placement and subsequent loading in the smile zone. We aimed to evaluate the long-term outcomes of simultaneous implant placement, soft tissue grafting, and immediate prosthetic loading in the esthetic zone.

Methods

Thirty-five implants were placed in the maxillary aesthetic zone. Twenty-two patients were evaluated using the Pink Esthetic Score (PES) and White Esthetic Score (WES). Also, the degree of peri-implant bone resorption and patient survey were applied for the esthetic and functional outcomes.

Results

The esthetic and harmonizing outcomes were achieved according to the mean total PES/WES value (17.9±2.0). The mean overall PES was 8.5±1.66. The papilla level had the highest mean score (1.8±0.36). Furthermore, the combination of root convexity/color and soft tissue color and texture was one of the key values in evaluating the effectiveness of this method (the mean value was 1.5±0.5). The mesial and distal papillae were 1.6±0.5 and 1.8±0.4, respectively. None of the 35 implants reached below 6 points (which is considered an esthetically unsatisfactory result). The mean WES score was 9.5±0.57. The average degree of total peri-implant bone resorption was 1.05±0.3 mm after 12 months. According to the questionnaire, all the patients smiled without hesitation and were satisfied with the treatment (100%).

Conclusion

This study showed that restoring one or more teeth in the smile zone using the concept of one-stage implant placement, soft tissue flap augmentation, and loading with provisional crowns was an esthetically successful and predictable method.

In Vitro Biodegradation Pattern of Collagen Matrices for Soft Tissue Augmentation

Collagen matrices have become a great alternative to the use of connective tissue grafts for soft tissue augmentation procedures. One of the main problems with these matrices is their volume instability and rapid degradation. This study has been designed with the objective of examining the degradation of three matrices over time. For this purpose, pieces of 10 × 10 mm² of Fibro-Gide, Mucograft and Mucoderm were submitted to three different degradation tests-(1) hydrolytic degradation in phosphate buffer solution (PBS); (2) enzyme resistance, using a 0.25% porcine trypsin solution; and (3) bacterial collagenase resistance (Clostridium histolyticum)-over different immersion periods of up to 50 days. Weight measurements were performed with an analytic microbalance. Thickness was measured with a digital caliper. A stereomicroscope was used to obtain the matrices' images. ANOVA and Student-Newman-Keuls tests were used for mean comparisons (p < 0.05), except when analyzing differences between time-points within the same matrix and solution, where pair-wise comparisons were applied (p < 0.001). Fibro-Gide attained the highest resistance to all degradation challenges. The bacterial collagenase solution was shown to constitute the most aggressive test as all matrices presented 100% degradation before 14 days of storage.

Tissue Response to a Porous Collagen Matrix Used for Soft Tissue Augmentation

A short inflammatory phase and fast ingrowth of blood vessels and mesenchymal cells are essential for tissue integration of a biomaterial. Macrophages play a key role in this process. We investigated invasion of macrophages, blood vessels, and proliferating cells into a highly porous and volume-stable collagen matrix (VCMX) used for soft tissue augmentation around teeth and dental implants. The biomaterial was implanted in submucosal pouches in the canine maxilla, and the tissue response was analyzed at six different time points. Immunohistochemistry was done for proliferating cells (PCNA), macrophages (MAC387), multinucleated giant cells (CD86), and blood vessels (TGM2). Blood rapidly filled the VCMX pores. During the first week, MAC387+ cells populated the VCMX pores, blood vessels and PCNA+ cells invaded the VCMX, and CD86+ scattered cells were observed. At 15 days, MAC387+ cells were scanty, blood vessels had completely invaded the VCMX, the number of proliferating cells peaked, and fibroblasts appeared. At 30 days, MAC387+ were absent, the numbers of proliferating and CD86+ cells had declined, while blood vessel and fibroblast numbers were high. At 90 days, residual VCMX was well-integrated in soft connective tissue. In conclusion, the VCMX elicited a short inflammatory phase followed by rapid tissue integration.

Dimensional Changes of the Soft Tissue after Alveolar Ridge Preservation with a Collagen Material. A Clinical Randomized Trial

Background:

Reduction of the soft tissue is an unavoidable consequence of tooth extraction without appropriate measures of Alveolar Ridge Preservation (ARP).

Objectives:

The objective of this study is the volumetric investigation of the dimensional change of the soft tissue post tooth extraction to compare an Alveolar Ridge Preservation (ARP) measure with the insertion of a combination material with a collagen cone to fill the alveolus, combined with a collagen membrane, with untreated extraction alveoli.

Methods:

In the context of a randomized clinical trial, 31 patients were treated with the combination material directly post tooth extraction in the maxilla (ARP). In 29 further patients, the extraction alveoli were left without further measures (control group).

The changes of the soft tissue contour were measured 6 (+/- 1) weeks post extraction. The measurements were performed by superimposing digital models. The groups were compared using the Wilcoxon rank-sum-test.

Results:

The premolar subgroup revealed a significant difference of the soft tissue dimension post insertion of a collagen material into the alveolus in comparison to untreated alveoli. In these cases, the mean loss of soft tissue volume after use of the collagen material was significantly lower.

Conclusion:

The proposed hypothesis that there is a difference of the soft tissue preservation between alveoli with and without the use of a collagen material can be accepted with restrictions to the premolar region. A statistically significant lower volume reduction of the soft tissue by implantation of the collagen material could be detected with premolars.

Evaluation of concordance between CAD/CAM and clinical positions of abutment shoulder against mucosal margin: an observational study

Background

While working on CAD/CAM-customized abutments, the use of standard impression copings with a circular diameter produces inconsistency within the emergence profile. It may begin with a collapse of the supra-implant mucosa during impression taking, then lead to a computer-generated mismatch of the position and outline of the abutment shoulder, and consequently result in a compromised outcome of anticipated treatment. The aim of the study was to compare the virtual and clinical positions of the abutment shoulder in relation to the mucosal margin after the abutment delivery.

Methods

Conventional open-tray impression takings followed uncovering surgery. Master casts were scanned with a desktop scanner. Clinical examinations took place after abutment’s insertion and temporization (T1) and prior to cementation of the definitive crown (T2). The distances between the abutment shoulder and marginal soft tissue were measured intraorally in four aspects and juxtaposed with those on the virtual model.

Results

The study evaluated 257 dental implants and CAD/CAM-customized abutments. As T1 and T2 showed, there was a positive correlation between the virtually designed abutment shoulder position and matching clinical location relative to the mucosal margin. In 42.1% of cases, the distance between the mucosal margin and the abutment shoulder did not change. It increased in 36.3% of cases while a decrease occurred in 21.6% of them.

Conclusions

Computer-set position of the abutment shoulder in relation to the mucosal margin can be predictably implemented in clinical practice.

A novel approach to treat peri implantitis with the help of PRF

A new field of biomédical science, known as tissue engineering, applies the principles of biology and engineering to the development of functional substitutes for tissues and organs. Little is known about the influence of Keratinised Mucosa dimension around implants on the soft and hard tissue health The purpose of this case report is to understand the importance of healthy tissue around the implants for long term success and how biomimetic materials like PRF Membrane can be incorporated in treatment plan as an important modality in selected cases.

Platelet-Rich Fibrin (PRF) in Implants Dentistry in Combination with New Bone Regenerative Flapless Technique: Evolution of the Technique and Final Results

Most common techniques for alveolar bone augmentation are guided bone regeneration (GBR) and autologous bone grafting. GBR studies demonstrated long-term reabsorption using heterologous bone graft. A general consensus has been achieved in implant surgery for a minimal amount of 2 mm of healthy bone around the implant. A current height loss of about 3-4 mm will result in proper deeper implant insertion when alveolar bone expansion is not planned because of the dome shape of the alveolar crest. To manage this situation a split crest technique has been proposed for alveolar bone expansion and the implants' insertion in one stage surgery. Platelet-rich fibrin (PRF) is a healing biomaterial with a great potential for bone and soft tissue regeneration without inflammatory reactions, and may be used alone or in combination with bone grafts, promoting hemostasis, bone growth, and maturation.

AIM

The aim of this study was to demonstrate the clinical effectiveness of PRF combined with a new split crest flapless modified technique in 5 patients vs. 5 control patients.

MATERIALS AND METHODS

Ten patients with horizontal alveolar crests deficiency were treated in this study, divided into 2 groups: Group 1 (test) of 5 patients treated by the flapless split crest new procedure; Group 2 (control) of 5 patients treated by traditional technique with deeper insertion of smaller implants without split crest. The follow-up was performed with x-ray orthopantomography and intraoral radiographs at T0 (before surgery), T1 (operation time), T2 (3 months) and T3 (6 months) post-operation.

RESULTS

All cases were successful; there were no problems at surgery and post-operative times. All implants succeeded osteointegration and all patients underwent uneventful prosthetic rehabilitation. Mean height bone loss was 1 mm, measured as bone-implant most coronal contact (Δ-BIC), and occurred at immediate T2 post-operative time (3 months). No alveolar bone height loss was detected at implant insertion time, which was instead identified in the control group because of deeper implant insertion.

CONCLUSION

This modified split crest technique combined with PRF appears to be reliable, safe, and to improve the clinical outcome of patients with horizontal alveolar crests deficiency compared to traditional implanting techniques by avoiding alveolar height-loss related to deeper insertion of smaller implants.

Soft tissue augmentation around osseointegrated and uncovered dental implants: a systematic review

OBJECTIVES

The aim was to compile the current knowledge about the efficacy of different soft tissue correction methods around osseointegrated, already uncovered and/or loaded (OU/L) implants with insufficient soft tissue conditions. Procedures to increase peri-implant keratinized mucosa (KM) width and/or soft tissue volume were considered.

MATERIALS AND METHODS

Screening of two databases: MEDLINE (PubMed) and EMBASE (OVID), and manual search of articles were performed. Human studies reporting on soft tissue augmentation/correction methods around OU/L implants up to June 30, 2016, were considered. Quality assessment of selected full-text articles to weight risk of bias was performed using the Cochrane collaboration's tool.

RESULTS

Overall, four randomized controlled trials (risk of bias = high/low) and five prospective studies (risk of bias = high) were included. Depending on the surgical techniques and graft materials, the enlargement of keratinized tissue (KT) ranged between 1.15 ± 0.81 and 2.57 ± 0.50 mm. The apically positioned partial thickness flap (APPTF), in combination with a free gingival graft (FGG), a subepithelial connective tissue graft (SCTG), or a xenogeneic graft material (XCM) were most effective. A coronally advanced flap (CAF) combined with SCTG in three, combined with allogenic graft materials (AMDA) in one, and a split thickness flap (STF) combined with SCTG in another study showed mean soft tissue recession coverage rates from 28 to 96.3 %. STF combined with XCM failed to improve peri-implant soft tissue coverage.

CONCLUSIONS

The three APPTF-techniques combined with FGG, SCTG, or XCM achieved comparable enlargements of peri-implant KT. Further, both STF and CAF, both in combination with SCTG, are equivalent regarding recession coverage rates. STF + XCM and CAF + AMDA did not reach significant coverage.

CLINICAL RELEVANCE

In case of soft tissue deficiency around OU/L dental implants, the selection of both an appropriate surgical technique and a suitable soft tissue graft material is of utmost clinical relevance.

Soft tissue augmentation procedures at second-stage surgery: a systematic review

OBJECTIVES

The aim of this systematic review was to evaluate the efficacy of different soft tissue augmentation/correction methods in terms of increasing the peri-implant width of keratinized mucosa (KM) and/or gain of soft tissue volume during second-stage surgery.

MATERIALS AND METHODS

Screening of two databases, MEDLINE (PubMed) and EMBASE (OVID), and hand search of related articles, were performed. Human studies reporting on soft tissue augmentation/correction methods around submucosally osseointegrated implants during second-stage surgery up to July 31, 2015 were considered. Quality assessment of the selected full-text articles was performed according to the Cochrane collaboration's tool to assess the risk of bias.

RESULTS

Overall, eight prospective studies (risk of bias: high) and two case series (risk of bias: high) were included. Depending on the surgical technique and graft material used, the enlargement of keratinized tissue (KT) ranged between -0.20 and 9.35 mm. An apically positioned partial-thickness flap/vestibuloplasty (APPTF/VP) in combination with a free gingival graft (FGG) or a xenogeneic graft material (XCM) was most effective. Applying a roll envelope flap (REF) or an APPTF in combination with a subepithelial connective tissue graft (SCTG), mean increases in soft tissue volumes of 2.41 and 3.10 mm, respectively, were achieved. Due to the heterogeneity of study designs, no meta-analysis could be performed.

CONCLUSIONS

Within the limitations of this review, regarding the enlargement of peri-implant KT, the APPTF in the maxilla and the APPTF/VP in combination with FGG or XCM in the lower and upper jaw seem to provide acceptable outcomes. To augment peri-implant soft tissue volume REF in the maxilla or APPTF + SCTG in the lower and upper jaw appear to be reliable treatment options.

CLINICAL RELEVANCE

The localization in the jaw and the clinical situation are crucial for the decision which second-stage procedure should be applied.

Small-diameter titanium grade IV and titanium-zirconium implants in edentulous mandibles: five-year results from a double-blind, randomized controlled trial

BACKGROUND

The aim of this study was to compare the 5-year survival and success rates of 3.3 mm dental implants either made from titanium-zirconium (TiZr) alloy or from Grade IV titanium (Ti Grade IV) in mandibular implant-based removable overdentures.

METHODS

The core study had a follow-up period of 36 months and was designed as a randomized, controlled, double-blind, split-mouth multicenter clinical trial. Patients with edentulous mandibles received two Straumann Bone Level implants (diameter 3.3 mm, SLActive®), one of TiZr (test) and one of Ti Grade IV (control), in the interforaminal region. This follow-up study recruited patients from the core study and evaluated the plaque and sulcus bleeding indices, radiographic crestal bone level, as well as implant survival and success 60 months after implant placement.

RESULTS

Of the 91 patients who initially received implants, 75 completed the 36 month follow-up and 49 were available for the 60 month examination. Two patients were excluded so that a total of 47 patients with an average age of 72 ± 8 years were analysed. The characteristics and 36-month performance of the present study cohort did not differ from the non-included initial participants (p > 0.05). In the period since the 36-month follow-up examination, no implant was lost. The cumulative implant survival rate was 98.9 % for the TiZr group and 97.8 % for the Ti Grade IV group. Crestal bone level changes at 60 months were not different in the test and control group (TiZr -0.60 ± 0.69 mm and Ti Grade IV -0.61 ± 0.83 mm; p = 0.96). The cumulative implant success rate after 60 months was 95.8 and 92.6 % for TiZr and Ti Grade IV, respectively.

CONCLUSIONS

After 60 months, the positive outcomes of the 36 month results for TiZr and Ti Grade IV implants were confirmed, with no significant differences with regard to crestal bone level change, clinical parameters and survival or success rates. TiZr implants performed equally well compared to conventional Ti Grade IV 3.3 mm diameter-reduced implants for mandibular removable overdentures.

TRIAL REGISTRATION

Registered on www.clinicaltrials.gov: NCT01878331.