Efficacy of a collagen matrix for soft tissue augmentation after implant placement compared to connective tissue grafts: A multicenter, noninferiority, randomized controlled trial.

OBJECTIVES: To test whether soft tissue volume augmentation using a collagen matrix (VCMX) leads to noninferior results in terms of gain of mucosal thickness at single implant sites, compared to connective tissue grafts (SCTG). METHODS: The study was designed as a multi-center randomized controlled clinical trial. Subjects in need of soft tissue volume augmentation at single tooth implant sites were consecutively recruited at nine centers. The deficient mucosal thickness at the implant sites (one per patient) was augmented by applying either a VCMX or a SCTG. Patients were examined at 120 days (abutment connection = primary endpoint), 180 days (final restoration), and 360 days (1-year after insertion of the final restoration). Outcome measures included: transmucosal probing of the mucosal thickness (crestal = primary outcome), profilometric measurements of the tissue volume, and patient-reported outcome measures (PROMs). RESULTS: Out of the 88 patients, 79 attended the one-year follow-up. The median increase of the crestal mucosal thickness between pre-augmentation and 120 days was 0.3 ± 2.1 mm in the VCMX group and 0.8 ± 1.6 mm in the SCTG group (p = .455). Non-inferiority of the VCMX compared to the SCTG was not observed. The respective numbers at the buccal aspect amounted to 0.9 ± 2.0 mm (VCMX) and 1.1 ± 1.4 mm (SCTG; p = .431). PROMs including pain perception favored the VCMX group. CONCLUSION: It remains inconclusive whether soft tissue augmentation using a VCMX is noninferior to SCTG in terms of crestal mucosal thickening at single implant sites. However, the use of collagen matrices favors PROMs especially pain perception, while achieving similar buccal volume gains along with comparable clinical and aesthetic parameters to SCTG.

In vitro efficacy of non-surgical and surgical implant surface decontamination methods in three different defect configurations in the presence or absence of a suprastructure.

OBJECTIVES: Analysis of the in vitro efficacy of non-surgical and surgical dental implant surface decontamination with or without suprastructure. MATERIALS AND METHODS: Three hundred and sixty implants were dipped in indelible red and distributed to 30°, 60°, or 90° angulated bone defect models. One hundred and twenty implants were used for each bone defect, 40 of which were assigned to a decontamination method (CUR: curette; SOSC: soundscaler; APA: air powder abrasion). Of these, 20 were subjected to a simulated non-surgical (NST) or surgical treatment (ST), with/without mucosa mask, of which 10 were carried out with (S+) or without (S-) suprastructure. Uncleaned implant surface was assessed by both-sided implant surface photography. Surface morphology changes were analyzed using scanning electron microscopy (SEM). RESULTS: Cleaning efficacy was significantly better within NST if the suprastructure was removed (p < 0.001). No significant difference was found within ST (p = 0.304). Overall, cleaning efficacy in the order APA > SOSC>CUR decreased significantly (p < 0.0001) for both S+ and S- in NST as well as ST. Separated by NST/ST, S+/S-, defect angulation and decontamination method, only isolated significant differences in cleaning efficacy were present. Linear regression analysis revealed significant associations of remnants with the treatment approach, decontamination method, and defect angle (p < 0.0001). SEM micrographs showed serious surface damage after use of CUR and SOSC. CONCLUSIONS: Suprastructure removal is an additional option to improve cleaning efficacy of non-surgical implant surface decontamination in this in vitro model.

Effect of Subgingival Instrumentation on Neutrophil Elastase and C-Reactive Protein in Grade B and C Periodontitis: Exploratory Analysis of a Prospective Cohort Study.

Background: Assessment of the effect of subgingival instrumentation (SI) on systemic inflammation in periodontitis grades B (BP) and C (CP). Methods: In this prospective cohort study, eight BP and 46 CP patients received SI. Data were collected prior to and 12 weeks after SI. Blood was sampled prior to, one day, 6, and 12 weeks after SI. Neutrophil elastase (NE), C-reactive protein (CRP), leukocyte count, lipopolysaccharide binding protein, interleukin 6 (IL-6) and IL-8 were assessed. Results: Both groups showed significant clinical improvement. NE was lower in BP than CP at baseline and 1 day after SI, while CRP was lower in BP than CP at baseline (p < 0.05). NE and CRP had a peak 1 day after SI (p < 0.05). Between-subjects effects due to CP (p = 0.042) and PISA (p = 0.005) occurred. Within-subjects NE change was confirmed and modulated by grade (p = 0.017), smoking (p = 0.029), number of teeth (p = 0.033), and PISA (p = 0.002). For CRP between-subjects effects due to BMI (p = 0.008) were seen. Within-subjects PISA modulated the change of CRP over time (p = 0.017). Conclusions: In untreated CP, NE and CRP were higher than in BP. SI results in better PPD and PISA reduction in BP than CP. Trial registration: Deutsches Register Klinischer Studien DRKS00026952 28 October 2021 registered retrospectively.

Tunnel technique with connective tissue graft versus coronally advanced flap with enamel matrix derivate for root coverage: 5-year results of an RCT using 3D digital measurement technology for volumetric comparison of soft tissue changes.

AIM: Comparison of the clinical efficacy (digitally volumetric, aesthetic, patient-centred outcomes) of tunnel technique (TUN) with subepithelial connective tissue graft (CTG) versus coronally advanced flap (CAF) with enamel matrix derivate (EMD) 5 years after gingival recession therapy. MATERIALS AND METHODS: In 18 patients contributing 36 RT1 recessions, study models were collected at baseline and follow-ups. Optical scans assessed recessions computer-assisted [recession depth, recession reduction (RECred), complete root coverage (CRC), percentage of root coverage (RC), pointwise (pTHK) and mean areal (aTHK) marginal soft tissue thickness]. Root coverage aesthetic Score (RES) was used for aesthetic evaluation and visual analogue scales for patient-centred data collection applied. RESULTS: Sixty months after surgery, 50.0% (TUN+CTG) and 0.0% (CAF+EMD) of sites showed CRC (p = 0.0118), 82.2% (TUN+CTG) and 32.0% (CAF+EMD) achieved RC, respectively (p = 0.0023). CTG achieved significantly better RECred (TUN+CTG: 1.75±0.74 mm; CAF+EMD: 0.50 ± 0.39 mm; p = 0.0009) and aTHK (TUN+CTG: 0.95 ± 0.41 mm; CAF+EMD: 0.26 ± 0.28 mm; p = 0.0013). RES showed superior outcomes (p = 0.0533) for TUN+CTG (6.86 ± 2.31) compared to CAF+EMD (4.63 ± 1.99). The study failed to find significant differences related to patient-centred outcomes (TUN+CTG: 8.30 ± 2.21; CAF+EMD: 7.50 ± 1.51; p = 0.1136). CONCLUSIONS: Five years after treatment, CTG resulted in better clinical and aesthetic outcomes than CAF+EMD. Increased THK was associated with improved outcomes for RECred and RC.

Tooth loss in periodontally compromised patients: Retrospective long-term results 10 years after active periodontal therapy - tooth-related outcomes.

BACKGROUND: Estimating prognosis of periodontally affected teeth at the beginning of supportive periodontal care (SPC) is an important component for further treatment planning. This study aimed to evaluate tooth loss (TL) during 10 years of SPC in periodontally compromised patients and to identify tooth-related factors affecting TL. METHODS: Patients were re-examined 120 ± 12 months after accomplishment of active periodontal therapy. TL was defined as primary outcome variable and tooth-related factors (abutment status, furcation involvement [FI], tooth mobility, mean periodontal probing depth [PD], and clinical attachment level [CAL] at beginning of SPC, and initial bone loss [BL]) were estimated based on an adjusted regression analyses model. RESULTS: Ninety-seven patients (51 females and 46 males; mean age, 65.3 ± 11 years) lost 119 of 2,323 teeth (overall TL [OTL]: 0.12 teeth/patient/y) during 10 years of SPC. Forty of these teeth (33.6%) were lost for periodontal reasons (TLP; 0.04 teeth/patient/y). Significantly more teeth were lost due to other reasons (P <0.0001). TLP (OTL) only occurred in 5.9% (14.7%) of all teeth, when BL was at least 80%. Use as abutment tooth, FI degree III, tooth mobility degrees I and II, mean PD, and CAL positively correlated with OTL (P <0.05). For TLP, FI and tooth mobility degree III as well as mean CAL were identified as tooth-related prognostic factors (P <0.05). CONCLUSIONS: During 10 years of SPC, most of the teeth (93.4%) of periodontally compromised patients were retained, showing the positive effect of a well-established treatment concept. Well-known tooth-related prognostic factors were confirmed.

In vitro surgical and non-surgical air-polishing efficacy for implant surface decontamination in three different defect configurations.

OBJECTIVES: Evaluation of surgical and non-surgical air-polishing in vitro efficacy for implant surface decontamination. MATERIAL AND METHODS: One hundred eighty implants were distributed to three differently angulated bone defect models (30°, 60°, 90°). Biofilm was imitated using indelible red color. Sixty implants were used for each defect, 20 of which were air-polished with three different types of glycine air powder abrasion (GAPA1-3) combinations. Within 20 equally air-polished implants, a surgical and non-surgical (with/without mucosa mask) procedure were simulated. All implants were photographed to determine the uncleaned surface. Changes in surface morphology were assessed using scanning electron micrographs (SEM). RESULTS: Cleaning efficacy did not show any significant differences between GAPA1-3 for surgical and non-surgical application. Within a cleaning method significant (p < 0.001) differences for GAPA2 between 30° (11.77 ± 2.73%) and 90° (7.25 ± 1.42%) in the non-surgical and 30° (8.26 ± 1.02%) and 60° (5.02 ± 0.84%) in the surgical simulation occurred. The surgical use of air-polishing (6.68 ± 1.66%) was significantly superior (p < 0.001) to the non-surgical (10.13 ± 2.75%). SEM micrographs showed no surface damages after use of GAPA. CONCLUSIONS: Air-polishing is an efficient, surface protective method for surgical and non-surgical implant surface decontamination in this in vitro model. No method resulted in a complete cleaning of the implant surface. CLINICAL RELEVANCE: Air-polishing appears to be promising for implant surface decontamination regardless of the device.

The socket-shield technique: a step-by-step protocol after 12 years of experience.

The socket-shield technique, first published in 2010, has gained worldwide scientific and clinical acceptance. To address possible complications with this innovative approach in esthetic implant dentistry, we provide a comprehensive step-by-step protocol incorporating what we have learnt in the past decade. After initial decoronation of the tooth, the implant bed is prepared through the root of the tooth to be extracted. Following extraction of the palatal root fragments, the shield is prepared according to either a mechanical or biologic 'locking' principle. The mechanical 'locking' comprises a direct contact between the implant and the shield, whereas the biologic approach facilitates ankylosis of the shield, preventing its coronal displacement. The coronal part of the shield is brought into a concave shape, ending up 0.5 mm coronal to the buccal bone. The implant is consequently inserted, and an individualized healing cap fabricated. When performed according to the underlying biologic and mechanical principles, the socket-shield technique can provide highly esthetic and predictable outcomes.

Tunnel technique with connective tissue graft versus coronally advanced flap with enamel matrix derivate for root coverage: 2-year results of an RCT using 3D digital measuring for volumetric comparison of gingival dimensions.

AIM: The aim of this randomized clinical trial was to compare clinical and volumetric outcomes of tunnel technique (TUN) with subepithelial connective tissue graft (CTG) versus coronally advanced flap (CAF) with enamel matrix derivate (EMD) 2 years after gingival recession (GR) treatment. MATERIALS AND METHODS: Twenty-three patients contributed 45 Miller class I or II GR. At baseline and follow-up examinations, study models were collected. Their three-dimensional scans allowed precise computer-assisted measurement of recession depth (REC), complete root coverage (CRC), percentage of root coverage (RC), pointwise (pTHK) and mean areal (aTHK) marginal soft tissue thickness. Clinical examination delivered probing depths (PPD) and height of keratinized tissue. RESULTS: 24 months after surgery, digitally evaluated CRC was present in 60.0% of the TUN + CTG and 0.0% of the CAF + EMD-treated sites (p < .0001), meaning a certain relapse of the gingival margin ragarding both approaches. RC amounted to 94.0% (TUN + CTG) and 57.3% (CAF + EMD), respectively (p < .0001). REC reduction (RECred) was significantly higher for TUN + CTG (1.81 ± 0.56 mm) than for CAF + EMD (0.90 ± 0.45 mm) (p < .0001). pTHK and aTHK values were significantly greater in the TUN + CTG group (1.41 ± 0.35 mm and 1.11 ± 0.26 mm) than in the CAF + EMD group (0.78 ± 0.32 mm and 0.60 ± 0.26 mm) (p < .0001). Statistical analysis detected positive correlations between THK and both RC and RECred (p < .001). CONCLUSIONS: Two years post-operatively, CTG showed better clinical and volumetric outcomes than EMD. Increased THK values were associated with improved outcomes regarding RC and RECred.

Complication Management of a Socket Shield Case After 6 Years of Function.

Maintaining soft and hard tissues around dental implants after tooth extraction is one of the major challenges in implant dentistry. After tooth extraction, the subsequent loss of bone and soft tissue is inevitable due to the partial resorption of the buccal bone plate. The recently described socket shield technique addresses the problem by maintaining the buccal piece of the tooth in the extraction socket in order to preserve the buccal bone. As with every new technique, specific complications, like infection of the buccal piece of the tooth, can occur. Herein, the authors present a clinical case that developed a complication with the socket shield technique and the consequential surgical management.

Surgery without papilla incision: tunneling flap procedures in plastic periodontal and implant surgery.

Diverse clinical advancements, together with some relevant technical innovations, have led to an increase in popularity of tunneling flap procedures in plastic periodontal and implant surgery in the recent past. This trend is further promoted by the fact that these techniques have lately been introduced to a considerably expanded range of indications. While originally described for the treatment of gingival recession-type defects, tunneling flap procedures may now be applied successfully in a variety of clinical situations in which augmentation of the soft tissues is indicated in the esthetic zone. Potential clinical scenarios include surgical thickening of thin buccal gingiva or peri-implant mucosa, alveolar ridge/socket preservation and implant second-stage surgery, as well as soft-tissue ridge augmentation or pontic site development. In this way, tunneling flap procedures developed from a technique, originally merely intended for surgical root coverage, into a capacious surgical conception in plastic periodontal and implant surgery. The purpose of this article is to provide a comprehensive overview on tunneling flap procedures, to introduce the successive development of the approach along with underlying ideas on surgical wound healing and to present contemporary clinical scenarios in step-by-step photograph-illustrated sequences, which aim to provide clinicians with guidance to help them integrate tunneling flap procedures into their daily clinical routine.

Multidisciplinary full-mouth rehabilitation with soft tissue regeneration in the esthetic zone.

OBJECTIVE: Oral rehabilitation often requires a multidisciplinary approach including restorative dentistry, prosthodontics, and periodontology to fulfill high esthetic and functional demands, frequently combined with changes in the vertical dimension. The presence of gingival recessions can be associated with numerous factors, such as brushing or preparation trauma and persistent inflammation of the gingiva due to inadequate marginal fit of restorations. Because gingival recessions can cause major esthetic and functional problems, obtaining stability of the gingival tissue around prosthetic restorations is of essential concern. Modifications of the occlusal vertical dimension require sufficient experience of the whole dental team. Especially in patients with functional problems and craniomandibular dysfunction, a newly defined occlusal position should be adequately tested and possibly adjusted. CLINICAL CONSIDERATIONS: This case report presents a complete prosthetic rehabilitation combined with a periodontal surgical approach for a patient with gingival recessions and functional/esthetic related problems. The vertical dimension was carefully defined through long-term polymethyl methacrylate provisionals as a communication tool between all parts involved. All-ceramic crowns were inserted after periodontal healing as definitive rehabilitation. CONCLUSIONS: Complex rehabilitation in patients with high esthetic demands including soft tissue corrections requires a multidisciplinary team approach that consists of periodontal surgeon, dentist and dental technician.

Xenogenic collagen matrix or autologous connective tissue graft as adjunct to coronally advanced flaps for coverage of multiple adjacent gingival recession: Randomized trial assessing non-inferiority in root coverage and superiority in oral health-related quality of life.

AIM: To evaluate the non-inferiority of the adjunct of a xenogeneic collagen matrix (CMX) or connective tissue graft (CTG) to coronally advanced flaps (CAF) for coverage of multiple adjacent recessions and compare superiority in patient-reported outcomes (PROM). MATERIAL AND METHODS: One hundred and eighty-seven subjects (92 CMX) with 485 recessions in 14 centres were randomized and followed up for 6 months. Patients filled daily diaries for 15 days to monitor patient-reported experience. The primary outcome was changed in position of the gingival margin. Multilevel analysis used centre, subject and tooth as levels and baseline parameters as covariates. RESULTS: Average baseline recession was 2.5 ± 1.0 mm. The surgery was 15.7 min shorter (95%CI from 11.9 to 19.6, p < .0001) and perceived lighter (11.9 VAS units, 95%CI from 4.6 to 19.1, p = .0014) in CMX subjects. Time to recovery was 1.8 days shorter in CMX. Six-month root coverage was 1.7 ± 1.1 mm for CMX and 2.1 ± 1.0 mm for CTG (difference of 0.44 mm, 95%CI from 0.25 to 0.63 mm). The upper limit of the confidence interval was over the non-inferiority margin of 0.25 mm. Odds of complete root coverage were significantly higher for CTG (OR = 4.0, 95% CI 1.8-8.8). CONCLUSION: Replacing CTG with CMX shortens time to recovery and decreases morbidity, but the tested generation of devices is probably inferior to autologous CTG in terms of root coverage. Significant variability in PROMs was observed among centres.

Wound closure and wound healing. Suture techniques in contemporary periodontal and implant surgery: Interactions, requirements, and practical considerations.

In contemporary reconstructive periodontal and implant surgery, attaining uncomplicated wound healing in the early postoperative healing phase is the key to achieving a successful treatment outcome and is of central interest, from the clinical as well as the scientific perspective. The realization of primary wound healing is the central challenge in most cases. Two of the evidence-based factors that affect postoperative wound healing can be influenced by the surgeon: the blood supply to the surgical site and postoperative wound stability. The surgical suture is a key determinant of whether adequate wound stability is achieved in this context without complicating the course of wound healing by exerting unnecessary trauma or excessive tensile strain on the wound edges. Therefore, the inclusion of anchors in the suturing process that make it possible to achieve the best wound stability possible is often an important key to success. This article provides an overview of the principles of successful wound closure that are relevant to postoperative wound healing in order to equip dentists with the tools needed for the correct, indication-specific selection and performance of surgical suturing techniques in daily practice.

Discomfort/pain due to periodontal and peri-implant probing: Implant type and age.

AIM: There is evidence that patients experience more discomfort/pain after peri-implant probing than periodontal probing. However, there are several plausible factors to additionally influence this observation: e.g., implant type, age, smoking. Thus, this study was designed to compare discomfort/pain after periodontal and peri-implant probing in different implant types. METHODS: Two dentists recruited and examined 80 patients, each of them exhibiting a dental implant with a contralateral natural tooth. Only two types of implants were included. Periodontal and peri-implant probing depths (PPD) and probing attachment level (PAL) were assessed. Whether implant or tooth were measured first was randomly assigned. Immediately after probing patients scored discomfort/pain using a visual analogue scale (VAS). RESULTS: Eighty patients (median; lower/upper quartile: age 57; 47.5/65.5 years; 40 females, 11 smokers) were examined. With the exception of PPD and PAL at the deepest site as well as mean PPD (p < .05) clinical parameters (PAL, bleeding on probing, suppuration) were well balanced between implants and teeth. Peri-implant probing (VAS: 9.0; 5.0/17.0) caused significantly (p = .038) more discomfort/pain than periodontal probing (5.5; 2.0/13.5). This was confirmed by repeated measures analysis of variance adjusting for several factors (p = .011). CONCLUSIONS: Peri-implant probing caused significantly more discomfort/pain than periodontal probing.

Socket Shield Technique for immediate implant placement - clinical, radiographic and volumetric data after 5 years.

OBJECTIVES: Implant placement immediately after tooth extraction is often accompanied by resorption of surrounding tissues. A clinical technique was developed where the buccal portion of the root is retained to preserve the periodontal ligament and bundle bone. This technique is based on animal studies showing the potential to preserve the facial tissues utilizing this approach. The purpose of this study was to gain more insight regarding the safety of the technique with regard to biological and implant-related long-term complications and to observe the clinical appearance of the peri-implant tissues. Another objective was to evaluate volumetric changes of the affected facial contours in long-term and the esthetic outcomes. MATERIAL AND METHODS: This study is a retrospective case series of 10 consecutive patients with implant replacement between the maxillary first premolars. Impressions were made prior to extraction (t1) and 5 years post-implant placement (t2). 3D-surface scans of the casts were digitally superimposed for quantitative evaluation of alterations of the facial peri-implant tissue contours and soft tissue recessions. Additionally, clinical data were collected (PPD, BOP, peri-apical radiographs and photographs). RESULTS: All implants healed without adverse events. Peri-implant probing revealed healthy conditions. The comparison of radiographic images showed physiologic bone remodeling at the implant shoulders. Mean tissue loss on the facial side in oro-facial direction was -0.21 ± 0.18 mm. Average recession at implants was -0.33 ± 0.23 mm and at neighboring teeth -0.38 ± 0.27 mm. Mean loss of the marginal bone level at the implant shoulder amounted to 0.33 ± 0.43 mm at the mesial and 0.17 ± 0.36 mm at the distal aspect of the implants. A mean pink esthetic score of 12 was recorded. CONCLUSION: Volumetric analysis showed a low degree of contour changes from extraction and implant placement to the follow-ups. Mucosal recession at the implant restoration was comparable to that of the neighboring teeth. Within the limitations of this descriptive study, the socket shield technique offers reduced invasiveness at the time of surgery and high esthetic outcomes with effective preservation of facial tissue contours. This technique should not be used in routine clinical practice until a higher level evidence in the form of prospective clinical trials is available.

Clinical Benefits of the Immediate Implant Socket Shield Technique.

OBJECTIVE: Extraction-socket resorption is considered a major problem that can limit implantological rehabilitation options and compromise the esthetic outcome. Surgical techniques to reduce remodeling are of restricted predictability and commonly require several surgical interventions and grafting. This increases the treatment cost and places a physical and psychological strain on the patient. This clinical case report presents a replacement of an upper canine using the socket-shield technique (SST) with a CAD/CAM surgical guide, resulting in a predictable, high esthetic, and functional result. CLINICAL CONSIDERATIONS: The SST is an alternative approach to curbing remodeling and resorption by retaining the facial part of the root during tooth extraction. An immediately placed implant supports the facial root fragment, preventing the collapse of the buccal wall. The SST with digital precision planning in combination with a CAD/CAM surgical guide benefits patients by preserving their tissue architecture and causing only insignificant trauma. Furthermore, the SST reduces the number of surgical and prosthetic interventions required to one each for pre-operative planning, surgical procedures, and prosthetic rehabilitation. CONCLUSIONS: The socket shield technique is a minimally invasive implantological approach offers patients and clinicians multiple benefits. CLINICAL SIGNIFICANCE: The socket-shield technique (SST) represents an alternative approach to intervene remodeling and resorption processes by the maintenance of the facial part of the root during tooth extraction. The immediate placement of an implant supports the facial root fragment and thereby prevents a collapse of the buccal wall. The SST associated with a CAD/CAM fabricated surgical guide, can reduce the amount of appointments, due to the immediate fabrication of the definitive restoration with the existing model. Therefore, no further necessary appointments are required apart from first pre-operative planning, second for surgical treatment, and third for prosthetic rehabilitation. (J Esthet Restor Dent 29:93-101, 2017).

Replacement of mandibular central incisors with implant-supported crowns: a case report.

Anterior teeth are often affected by accidental dental trauma and may eventually be lost. When the neighboring teeth are unharmed, implant-supported crowns are often the preferred treatment choice. When not only the teeth but also the supporting hard and soft tissue has been lost, surgical reconstruction may be needed. However, in combined horizontal and vertical class III defects, the available augmentation techniques are often not predictable. In this case report, two neighboring mandibular central incisors were replaced by two implants after soft and hard tissue augmentation with the cortical bone plate method. The interdental soft tissue was reconstructed with remarkable success, making this an example of what can be achieved in cases such as this.

Socket seal surgery: Clinical uses in implant dentistry and guided bone regeneration procedures for single tooth replacement in the esthetic zone.

Restoring failing anterior teeth with a dental implant is considered a complex treatment even with thorough biologic knowledge of the situation. The goal is to produce a result in which the labial soft tissues and the papillae remain stable over time. Treatment of the fresh extraction socket in the alveolar ridge presents a challenge in everyday clinical practice. Regardless of the subsequent treatment, maintenance of the ridge contour will frequently facilitate all further therapeutic steps. Socket seal surgery and socket preservation in combination with immediate, early, or delayed implant placement can be valuable procedures for single tooth replacement. However, their potential as ridge preservation techniques in these different situations still needs to be demonstrated. The use of these procedures is illustrated in three consecutive cases.

Long-term stability of peri-implant tissues after bone or soft tissue augmentation. Effect of zirconia or titanium abutments on peri-implant soft tissues. Summary and consensus statements. The 4th EAO Consensus Conference 2015.

INTRODUCTION: Several surgical techniques and prosthetic devices have been developed in the last decades, aiming to improve aesthetic, hygienic and functional outcomes that may affect the peri-implant tissues, such as procedures of bone and soft tissue augmentation and the use of custom-made abutments of titanium and zirconium. MATERIALS AND METHODS: Three systematic reviews, based on randomized clinical trials and prospective studies covering the above reported topics were analysed, and the detected evidence was exposed to interactive experts' discussion during the group's and general assembly's meetings of the 4th EAO Consensus Conference. The results are reported using the following abbreviations: S-T: short-term evidence, M-T: medium-term evidence; L-T: long-term evidence; LE: limited evidence. RESULTS: Soft tissue augmentation procedures may be indicated for the increase of soft tissue thickness and keratinized tissue, the reduction of interproximal peri-implant bone loss, and the coverage of shallow peri-implant soft tissue recessions (S-T, LE), L-T is lacking. Guided bone regeneration approaches (GBR) showed efficacy when used for ridge reconstruction after the complete healing of the soft tissues (S-T & L-T), and the stability of the augmented bone may play a role in the maintenance of the soft tissue position and dimensions (LE). No significant differences were observed between titanium and zirconia abutments when evaluating probing pocket depth, bleeding on probing, marginal bone levels and mucosal recessions. Zirconia abutments were associated with more biological complications but demonstrated superiority in terms of achieving natural soft tissue colour (S-T).