Immediate Provisionalization of Dental Implants Placed in Healed Alveolar Ridges and Extraction Sockets: A 5-year Prospective Evaluation

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1 Immediate Provisionalization of Dental Implants Placed in Healed Alveolar Ridges and Extraction Sockets: A 5-year Prospective Evaluation Lyndon F. Cooper, DDS, PhD 1 /Glenn J. Reside, DDS 2 /Filiep Raes, DDS, PhD 3 / Joan Soliva Garriga, DDS, DMD 4 /Luis Giner Tarrida, DDS, DMD, PhD 5 / Jörg Wiltfang, MD, DMD 6 /Matthias Kern, DMD 7 /Hugo De Bruyn, DDS, PhD 8 Purpose: This 5-year prospective multicenter study compared implant survival and success, peri-implant health and soft tissue responses, crestal bone level stability, and complication rates following immediate loading of single OsseoSpeed implants placed in anterior maxillary healed ridges or extraction sockets. Materials and Methods: Individuals requiring anterior tooth replacement with single implants were treated and immediately provisionalized. Definitive all-ceramic crowns were placed at 12 weeks. Implant survival, bone levels, soft tissue levels, and peri-implant health were monitored for 5 years. Results: One hundred thirteen patients received implants in fresh sockets (55) and healed ridges (58). After 5 years, 45 and 49 patients remained for evaluation, respectively. During the first year, three implants failed in the extraction socket group (94.6% survival) and one implant failed in the healed ridge group (98.3% survival); this difference was not significant. No further implant failures were recorded. After 5 years, the interproximal crestal bone levels were located a mean of 0.43 ± 0.63 mm and 0.38 ± 0.62 mm from the reference points of implants in sockets and healed ridges (not a significant difference). In both groups, papillae increased over time and peri-implant mucosal zenith positions were stable from the time of definitive crown placement in sockets and healed ridges. Compared to flap surgery for implants in healed ridges, flapless surgery resulted in increased peri-implant mucosal tissue dimension (average, 0.78 ± 1.34 mm vs 0.19 ± 0.79 mm). Conclusion: After 5 years, the bone and soft tissue parameters that characterize implant success and contribute to dental implant esthetics were similar following the immediate provisionalization of implants in sockets and healed ridges. The overall tissue responses and reported implant survival support the immediate provisionalization of dental implants in situations involving healed ridges and, under ideal circumstances, extraction sockets. Int J Oral Maxillofac Implants 2014;29: doi: /jomi.3617 Key words: dental implants, extraction socket, immediate loading, marginal bone level, soft tissue When a tooth fails and cannot be rehabilitated, its replacement after extraction may be managed using a variety of different pathways. Single-tooth replacement may be successful using different therapies. 1 One such therapy involving dental implants is extraction of the tooth, followed by immediate placement 1 Stallings Distinguished Professor and Chair, Department of Prosthodontics, University of North Carolina, Chapel Hill, North Carolina. 2 Clinical Associate Professor, Department of Oral and Maxillofacial Surgery, University of North Carolina, Chapel Hill, North Carolina. 3 Associate Professor, Department of Periodontology and Oral Implantology, Faculty of Medicine and Health Sciences, Dental School, University of Ghent, Ghent, Belgium. 4 Associate Professor, Department of Prosthodontics, Dentistry School, Universitat Internacional de Catalunya, Catalunya, Spain. 5 Dean, Research Department, Dentistry School, Universitat Internacional de Catalunya, Catalunya, Spain. of a dental implant in the residual alveolar bone and restoration with an abutment and a provisional crown free of occlusal contacts. This immediate placement and provisionalization strategy has been explored in many case reports and clinical studies over the past decade (reviewed by den Hartog et al 2 ). Specifically, 6 Professor and Chair, Department of Oral and Maxillofacial Surgery, University of Schleswig-Holstein, Campus Kiel, Germany. 7 Professor and Chair, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Kiel, Germany. 8 Professor and Chair, Department of Periodontology and Oral Implantology, Faculty of Medicine and Health Sciences, Dental School, University of Ghent Belgium; Department of Prosthodontics, University of Malmo, Malmo, Sweden. Correspondence to: Lyndon F. Cooper, Department of Prosthodontics, 330 Brauer Hall, CB#7450, University of North Carolina, Chapel Hill, NC lyndon_cooper@unc.edu 2014 by Quintessence Publishing Co Inc. The International Journal of Oral & Maxillofacial Implants 709

2 several early reports have revealed that immediate provisionalization of unsplinted implants in sockets predictably results in osseointegration. 3 8 These early investigations share common requirements for treatment, which include good primary stability of the implant, the absence of occlusal or eccentric contacts during the healing period, and the adoption of strict inclusion and exclusion criteria. The effect of function on the osseointegration process may lead to increased density of newly formed peri-implant bone compared to unloaded implants. 9 Upon the inception of this strategy of immediate placement and provisionalization, the initial experimental questions focused on implant osseointegration and implant survival. Recently, several systematic reviews have been published regarding single-tooth replacement using dental implants. Knoernschild 10 indicated that both early/ immediate and conventional surgical procedures provide favorable short-term outcomes regarding implant survival. As suggested, the timing of implant loading may not dramatically affect implant survival. However, these early investigations considered a narrow range of success criteria for single implants. More recently, clinical interest in esthetic outcomes, prosthetic and component outcomes, and patient-based measures of success has increased. For example, Esposito and colleagues 11 suggested that the esthetic outcome might be better if implants were placed immediately after tooth extraction. While short-term positive data exist at the level of implant survival, significant questions remain regarding esthetic outcomes, soft tissue responses, and patient satisfaction. 2 Esthetic determinants of dental therapy have emerged as highly significant among both clinicians and patients. For anterior dental implants, esthetic outcomes are strongly related to peri-implant mucosal architecture. 12 Tools for esthetic assessment of dental implants have been adopted. The Pink Esthetic Score 13 is commonly employed in the assessment of anterior dental implants. Objective assessments of buccal tissue architecture and interproximal tissue form (papillae) contribute to this evaluation. A complimentary White Esthetic Score is also valuable in the objective assessment of the related implant crown. 14 Objective assessments of implant esthetic outcomes assist in clinical decision-making and may avoid patient dissatisfaction. These tools may permit more careful assessment of clinical therapeutic choices regarding the timing of implant placement, loading, and definitive restoration. It is widely appreciated that alveolar and periimplant tissues display time-dependent alterations following both tooth extraction and dental implant placement. For example, extraction results in alveolar ridge resorption, favoring buccal bone loss. The magnitude of this resorption may approach 30% to 40% 15,16 and is attributable, in part, to rapid postextraction resorption of the bundle bone. 17 Placement of a dental implant into the fresh socket appears not to alter this resorptive process. With the loss of buccal bone represented in these studies, immediate implant placement may make the restoration of tooth and alveolar form presented prior to extraction challenging. The alterations in soft tissue contours at dental implant crowns may be negatively affected. Kan et al, 3 for example, indicated that the buccal tissues around implants placed in extraction sockets experience recession of approximately 0.5 mm. Evans and Chen 18 recorded recession of 0.9 mm. In contrast, Block et al 19 recorded virtually no soft tissue recession after immediate provisionalization of implants in sockets. The timing of restoration, however, was not a distinguishing variable of outcomes when De Rouck et al 20 examined this phenomenon in a prospective comparison involving 24 implants. Recently, Cosyn et al 21 showed that immediate implant treatment or standard implant treatment were comparable with regard to implant survival and soft tissue outcomes but related incomplete papilla repair after implant placement to the presence of periodontal disease and thin, scalloped soft tissue. Again, these data indicate that important questions remain regarding the clinical and biologic outcomes following immediate placement and provisionalization of implants within extraction sockets. The aim of the present investigation was to compare the clinical and radiographic outcomes of implant crowns 1 year after immediate placement and provisionalization in healed ridges and extraction sockets. The primary outcome measure was implant survival. Secondary outcome measures included changes in interproximal crestal bone levels, papillae, and buccal gingival zenith position. The null hypothesis was that there is no difference in implant survival between implants placed in healed ridges and those placed in extraction sockets at 5 years following treatment. Materials and Methods Comparison of the 5-year outcomes of immediate provisionalization of endosseous implants placed in extraction sockets and healed ridges was conducted as a multicenter, prospective, noninferiority clinical trial in four centers under a single protocol that had received local institutional review board approval and the informed consent from all subjects. The details of this clinical protocol have been reported previously. 22,23 Patients in need of replacement of one or more single missing or failing teeth in the maxilla between and including the first premolars (teeth 15 to 25) were 710 Volume 29, Number 3, 2014

3 recruited. Adjacent implant sites were excluded. All included patients possessed the following inclusion criteria: need for a single implant to replace missing, extracted, or avulsed maxillary teeth in the anterior maxilla; presence of a minimum of 20 teeth with stable intraocclusal contacts; age at least 18 years; and provision of written informed consent. Patients were excluded if they demonstrated tobacco use, abuse of drugs or alcohol; if they had received bone augmentation in the planned implant area within 4 months; if they had a history of extraction in the planned implant area within the past 3 months; if the opposing dentition or adjacent natural tooth root were absent; if uncontrolled diabetes, pregnancy at time of inclusion, or any systemic or local disease or condition that would compromise postoperative healing and/or osseointegration was present; if they required systemic corticosteroids or any other medication that would compromise postoperative healing and/or osseointegration; or if they were unable or unwilling to return for follow-up visits for 5 years. Patients with unrealistic esthetic demands or who were unlikely to comply with study procedures according to the investigators judgment were not included. Because the study compared two treatment protocols, neither blinding of the investigators nor the patients was possible. Treatment Groups Patients were clinically divided into extraction socket and healed ridge treatment groups. If during implant surgery, inappropriate bone volume, or crestal defects that required bone regeneration were present, the site was grafted using anorganic bovine bone (Bio- Oss, Osteohealth) covered with a resorbable collagen membrane (Bio-Gide/Bio-Mend, Osteohealth). These patients were consequently not treated according to protocol and therefore segregated into a third (grafted site) group. If at the time of implant placement, primary implant stability was not achieved, the implant was excluded from further investigation. Implant Treatment OsseoSpeed implants (Dentsply Implants), 3.5 to 5.0 mm in diameter and 11 to 17 mm in length, were used. Implant placement was performed under local anesthesia, and appropriate pre- and postoperative antiinfective measures were taken. Implant placement in both alveolar ridges and fresh sockets was done without grafting gaps between implants and alveolar socket walls. While a flapless approach was typically advocated, mucoperiosteal flaps were elevated as required for placement of implants into 15 of 55 sockets and into 30 of 58 healed ridges. The decision to elevate a flap was made during implant placement based on the surgeons effort to fully define the integrity of the buccal bone or to better visualize the bone crest for proper implant placement. Osteotomies were initiated with a small round bur, followed by a 2.0-mm drill to depth. Progression to 3.2 mm in diameter (for 3.5-mm and 4.5- mm implants) or 3.7 mm in diameter (for 4.0- and 5.0- mm implants) was performed using the manufacturer s protocol. The integrity of the buccal bone was evaluated by probing after each bur sequence. The horizontal distances from the implant to the buccal and lingual sides of the bone crest were measured using a UNC 15 probe (± 0.5 mm). Implant stability was assessed clinically as the absence of axial rotation or movement. Stable implants were provisionalized with titanium abutments and cemented acrylic resin crowns that were adapted to the abutment margin using an extraoral step on the abutment analog and highly polished. The crowns were evaluated for the absence of centric or eccentric contacts using articulating paper and adjusted to ensure this result. The provisional crowns were luted with temporary cement, eg, Temp-Bond NE (Kerr). Eight weeks later, the provisional was removed and the abutment was retightened to 20 to 25 Ncm, which confirmed osseointegration. An impression was made and a definitive all-ceramic crown (Procera, Nobel Biocare) was fabricated. At 11 to 12 weeks, the definitive crown was cemented with glass ionomer (Ketac Cem, 3M ESPE). The finish line of the crowns was kept 0.5 to 1 mm subgingival to facilitate the complete removal of cement. Clinical and Radiographic Assessments All patients were examined 7 to 10 days after implant placement. The occlusion was again examined and adjusted, if needed, to avoid centric and excursive contacts during the initial healing period. Peri-implant bone levels were evaluated with periapical radiographs at baseline (day of implant and provisional crown placement), at definitive crown delivery (11 to 12 weeks), after 6 months, and at 1, 2, 3, 4, and 5 years after implant placement. The distance from the interproximal bone to the reference point (outer aspect of the implant bevel) on both the mesial and distal aspects of the implant was measured to the nearest 0.1 mm by an independent radiologist, and the mean of these two measurements was calculated for each implant. The changes from baseline were calculated for each subsequent time point. The presence or absence of plaque and the incidence of bleeding by light probing of the peri-implant mucosa was evaluated at the four aspects of each implant crown (mesiolingual, distolingual, mesiobuccal, and distobuccal). The peri-implant mucosal zenith score (linear distance from the zenith of the peri-implant mucosa to the incisal reference line) and the papilla score (linear distance from the mesial and distal The International Journal of Oral & Maxillofacial Implants 711

4 Baseline (implant placement) 1 y 3 y Extraction socket group 55 implants 3 failures, 1 LTF 51 implants 3 LTF 48 implants 3 LTF Healed ridge group 58 implants 1 failure 57 implants 2 LTF 55 implants 6 LTF described previously, patients with 25 sites required grafting and were further segregated from this analysis. The remaining 62 extraction sites in 58 patients and 70 healed sites in 63 subjects were enrolled for implant placement and immediate loading. After exclusion of mobile implants at placement and additional randomization to one implant per subject, 113 implants/subjects were included. Fifty-five patients received implants in extraction sockets, and 58 patients received implants in healed ridges. 5 y papillae tips to the incisal edge of the neighboring tooth) were measured clinically (± 0.5 mm) with a UNC 15 periodontal probe. The changes in these measurements from the time of provisional placement and/or definitive crown placement to each time point were calculated, as appropriate. Statistical Analysis The statistical power calculation indicated that 48 evaluable patients would be needed in each group to accept or reject the null hypothesis that no difference existed in implant survival rate between the groups (80% power and 5% significance level). Each patient was represented by one implant, allowing the patient to be used as the statistical unit. When multiple implants were placed, the one implant monitored was selected by a computer-based randomization procedure. Descriptive statistics were used to analyze patient and implant characteristics. Nonparametric tests were used; the Fisher exact test was used to test for differences regarding implant survival. Within-group changes over time were evaluated with the Wilcoxon signed rank test. The Mann-Whitney U test was used to analyze differences between the groups in terms of hard and soft tissue parameters. The level of significance was set at.05 for each test, with no correction for multiple testing. Results 45 implants 49 implants Fig 1 Patient disposition from baseline to year 5. The numbers of patients (implants) receiving implants at baseline in the extraction socket and healed ridge groups are indicated. The number of patients experiencing implant failure and the number of patients lost to follow-up (LTF) are indicated for each interval (baseline to 1 year, 1 to 3 years, and 3 to 5 years). Patient Demographics One hundred thirty-nine patients with 157 sites were recruited according to therapeutic need into the extraction socket and healed ridge groups (Fig 1). As Treatment Outcome The enrolled patients received treatment according to the designated protocol, which resulted in different treatment groups with implants of varying lengths and diameters. As shown in Table 1, longer and wider implants were placed in the extraction socket group than in the healed ridge group. In addition, with respect to the distribution of implants among the different tooth positions, more implants were placed in canine extraction sites than in canine healed ridge sites. A larger number of implants were placed in second premolar healed ridges than extraction sockets (Fig 2). Regarding implant survival, 3 of 55 implants (5.4%) failed (between 26 and 184 days) in the extraction site group, while 1 of 58 (1.7%) failed (at 12 days) in the healed ridge group. During the remaining evaluation period, no further implant failures were observed. However, seven implants were lost to follow-up in the extraction group and eight implants were lost to follow-up in the healed ridge group. At 5 years, 45 and 49 implants were evaluated in the extraction socket and healed ridge groups, respectively. The Kaplan-Meier survival proportions were 0.95 and 0.98, respectively (no statistically significant difference), and the overall survival proportion was 0.96 (Table 2). With respect to the included patients of each group, only minor differences were reported for age and sex. The mean ages of the extraction socket and healed ridge groups were 45 (± 14) years and 42 (± 15) years, respectively. In the extraction socket and healed ridge groups, 60% and 57%, respectively, were women. The initial plaque scores were higher for the healed ridge group (24%) than for the extraction socket group (16%). The bone quality and quantity of the sites were similar in the two treatment groups. More than 90% of the sites were estimated to have type A or B quantity, and greater than 60% of the sites presented with type 1 or 2 quality bone in both groups. No type 4 quality bone was encountered in either group. Peri-implant Bone Response The radiographically measured distances from interproximal bone to the reference point (outer aspect of the implant bevel) revealed differences between the 712 Volume 29, Number 3, 2014

5 Table 1 distribution of Implants According to Length and Diameter Length (mm) Total (%) Diameter Ext H Ext H Ext H Ext H Ext H (3.6) 13 (22.4) (18.2) 27 (46.6) (32.7) 16 (27.6) (45.5) 2 (3.4) N (%) 3 (5.5) 13 (22.4) 14 (25.5) 23 (39.7) 17 (30.9) 10 (17.2) 21 (38.2) 12 (20.7) Ext = extraction site; H = healed ridge. Table 2 implant Survival Rate (Kaplan-Meier) in Extraction (Ext) and Healed Ridge (H) Groups At risk Failures Censored* Interval survival probability Survival proportion Interval Ext H Ext H Ext H Ext H Ext H IP (visit 2) IP to visit 6 (definitive crown) V6 to visit 7 ( 6 mo) V7 to visit 8 ( 12 mo) V8 to visit 9 ( 24 mo) V9 to visit 10 ( 36 mo) V10 to visit 11 ( 48 mo) V11 to visit 12 ( 60 mo) Visit 12 ( 60 mo) Totals *Censored = lost to follow-up. IP = implant placement. extraction socket and healed ridge groups that diminished with time (Fig 3). For implants placed in healed ridges, the mean marginal bone levels (means ± standard deviations [SDs]) changed little, from 0.47 ± 0.97 mm at placement to 0.38 ± 0.62 mm at 5 years. The marginal bone levels in extraction sockets reflected bone accrual along the implant surface, such that the location at implant placement (2.21 ± 2.46 mm) was crestal after 5 years (0.43 ± 0.63 mm) and not different from the healed ridge marginal bone level (Fig 3). In terms of the magnitude of bone changes at the interproximal sites of the implants, 2.06 ± 2.38 mm of bone gain was revealed along the implants in extraction sites and 0.1 ± 1.29 mm of bone gain was measured along implants placed in healed ridges during the 5-year follow-up period. Notably, 59% of implants in the healed ridge group demonstrated gain or no marginal bone change, and only 21.6% revealed marginal bone loss greater than 0.5 mm. Nearly all implants in the extraction socket group revealed bone gain (P <.05) (Fig 4). Peri-implant Mucosal Responses Bleeding on probing measurements revealed low values throughout the study. The plaque indices recorded No. of implants Central Lateral Canine First premolar Location 7 Second premolar Fig 2 Distribution of implants. The number of implants is represented for each tooth position (bilaterally) for implants placed in the extraction and healed ridge groups. were also low during the course of the study. The low levels (< 10%) for each index did reveal minor increases during the investigation period (Table 3) Extraction Healed 16 The International Journal of Oral & Maxillofacial Implants 713

6 Mean MBL (mm) IP 12 wk 26 IP wk + IP 1 + y Time 2 y Extraction Healed Extraction Healed 3 y 4 y 5 y Fig 3 Marginal bone levels (average mesial/distal), measured as the distance from the implant reference point to the marginal bone. Mean marginal bone values (± 1 standard deviation [SD]) are shown at implant placement (IP), definitive restoration ( 12 wk), and the follow-up visits. A two-sided P value <.05 was considered statistically significant. Bone levels at IP and 12 wk were statistically significantly different (P <.05). Cumulative % of implants Extraction group (A) Healed group (B) MBL change from IP to 5 y (mm) Fig 4 Cumulative radiographic interproximal bone level changes between implant placement (IP) and the 5-year follow-up. An important secondary aim of this study was the evaluation of the soft tissue changes at these implants over 5 years. Direct intraoral linear measurements of papillae distances on implants placed in extraction sockets demonstrated essentially no changes in mesial or distal papillae during the first 3 years and only minor changes of 0.13 ± 1.61 mm and 0.21 ± 1.61 mm, respectively, at the 5-year follow-up. For implants in the healed ridge group, increased papilla length (mesial: 0.35 ± 1.40 mm, distal: 0.64 ± 1.52 mm) was measured in the first 3 years, and little additional change had occurred at 5 years (mesial: 0.39 ± 1.52 mm, distal: 0.5 ± 1.35 mm) (Table 4). The peri-implant mucosal zenith score, a direct linear measurement of the distance of the mucosal zenith to the incisal edge, was stable from definitive crown placement to the 5-year time point (Table 5). This stable 5-year finding was found for 65.2% and 80.5% of crowns on implants placed in extraction sockets and healed ridges, respectively (Fig 5). When the mucosal zenith positions were compared as a function of time, minor differences in stability over the 5-year time period were identified when the outcomes were secondarily examined according to the use of a flap or flapless approach for implant placement. Figure 6 shows a small gain in mucosal zenith position (movement toward the incisal edge) from 1 to 5 years for implants placed in healed ridges using a flapless approach (0.78 ± 1.34 mm). In contrast, minor apical movement of the mucosal zenith position was observed for implants placed with a flapless approach in extraction sockets ( 0.05 ± 0.92 mm). Discussion This 5-year prospective study comparing the outcomes of dental implants placed into extraction sockets and healed ridges demonstrated high implant survival rates and stable clinical and radiographic outcomes following delivery of the definitive crown. In this investigation involving immediate provisionalization, the overall implant survival rate of 96.5% meets the expectations revealed by a recent systematic review of single-tooth implants. 8 The consideration of 3,223 implants in this review revealed a single-tooth implant survival rate after 5 years of 97.5%. The 1-year survival meta-analysis of implants in the esthetic zone performed by den Hartog et al 2 revealed an overall survival rate of 95.5% (95% confidence interval: 93.0% to 97.1%) irrespective of the type of intervention. The authors further indicated that studies of the most aggressive approach immediate implant placement and immediate loading showed no implant losses. These favorable outcomes in terms of implant survival have been supported by other systematic reviews. 2,10,24 The present 5-year survival data confirm the high survival rates of implants placed into extraction sockets followed by immediate provisionalization. They further confirm the reduced, but statistically insignificant, survival rates for implants placed in fresh extraction sockets compared to healed ridges. 25 The potential additional risk presented by extraction sockets may reflect the diverse architecture of the remaining sockets 714 Volume 29, Number 3, 2014

7 % of crowns % of crowns % 4.7% 2.3% 16.3% 30.2% 14.0% 15.2% 15.2% 7.0% 7.0% 7.0% 28.3% 28.3% % 2.2% 2.2% 2.2% 2.2% Change in gingival zenith Extraction Healed Fig 5 Distribution in magnitude of peri-implant mucosal zenith changes 5 years following definitive crown placement. The percentage of implant crowns displaying 2.0 to 6.0 mm of change in peri-implant mucosal zenith position at crowns on implants in extraction sockets and healed ridges is shown. Vertical line = 0 mm. and alveolar ridges. High implant survival and success rates can be achieved only when the stringent inclusion and exclusion criteria imposed by the investigation protocol are followed in clinical practice. Over the 5-year evaluation period, the interproximal bone levels at implants placed in sockets and healed ridges attained a position within 0.5 mm of the established reference point. As indicated in a previous publication, this complete filling or apposition and maintenance of bone occurred over a 3-year period and may reflect a prolonged bone adaptation period. 22 This approximation of bone with the implant/ abutment interface has been reported consistently for this particular implant/abutment configuration and has been shown to occur in the context of immediate provisionalization. Donati et al 9 demonstrated minimal changes in marginal bone levels after 5 years, and continued stability was suggested in a recent 10-year prospective report. 26 It has been suggested that the technique of immediate placement and provisionalization offers potential advantages for esthetic outcomes of single anterior implant restorations. 27 The possible preservation of tissue architecture surrounding the crown emphasizes this concept. An important secondary outcome of the current investigation was to compare the peri-implant tissue responses at midfacial and interproximal (papilla) locations of implants placed into healed ridges and sockets. Here, favorable responses were seen in Table 3 Frequency of Bleeding on Probing and Plaque Group/% of surfaces 2 wk 12 wk* 1 y 3 y Table 4 Mean Changes in Papilla from Definitive Crown Placement Mesial papilla Distal papilla Time/group N Mean SD n Mean SD 12 wk Ext H y Ext H y Ext H y Ext H Positive values represent gain, negative values loss. IP = implant placement; Ext = extraction; H = healed ridge. Table 5 Mean Changes in Gingival Zenith Location 5 y Extraction socket Bleeding Plaque Healed ridge Bleeding Plaque IP = implant placement. *Definitive crown delivery. Values represent average of four surfaces (mesiobuccal, distobuccal, mesiolingual, distolingual) as evaluated clinically. Mucosal zenith Time/group N Mean SD DR + 1 y Ext H DR + 3 y Ext H DR + 5 y Ext H Changes are shown relative to incisal edge from the time of definitive crown placement. DR = definitive restoration. both groups, with no midfacial resorption and stable papilla length measured from baseline. The investigation demonstrates the potential to effectively manage peri-implant mucosal tissues in a predictable fashion. Multiple factors may influence the location and stability of the peri-implant mucosal zenith. Included are the peri-implant biotype, the facial bone crest level, the implant angle, the interproximal bone crest level, the depth of implant platform, and the level of first The International Journal of Oral & Maxillofacial Implants 715

8 Mucosal zenith position (mm) y Healed ridge flapless Healed ridge flap Extraction socket flapless Extraction socket flap Fig 6 Longitudinal assessment of change in peri-implant mucosal zenith scores. The calculated average change in position of the peri-implant mucosal zenith at implants placed in extraction sockets or healed ridges using a flap (dashed lines) or flapless (solid lines) procedure are plotted versus the interval from crown placement to 1, 3, or 5 years. Negative values represent mucosal tissue recession. bone-to-implant contact. 28 None of these specific factors, other than marked bone resorption facially or interproximally and the location of the implant relative to the facial bone crest at placement, were specifically controlled by this protocol. The 5-year measurements of peri-implant mucosal zenith revealed no change or improvement (growth) for the majority of implants in both the extraction socket and healed ridge groups. Further stratification of the current two groups into implants placed using a flapped or flapless procedure revealed minor differences. The issue of the safety and efficacy of flapless surgery has been considered, 29 and it is generally accepted that flapless procedures offer esthetic advantages. However, few comparative studies have provided insight into the effect of the surgical approach on soft tissue parameters affecting implant esthetics. Recently, Bashutski et al 30 reported in a 15-month follow-up that there was no difference in this esthetic parameter between flapped and flapless approaches. While the present study was not designed specifically to compare flapped and flapless procedures, slight differences were revealed at the 5-year evaluation. Minor incisal movement of the peri-implant mucosal position was observed after 5 years around implants placed into healed ridges using a flapless approach, but not for implants placed into extraction sockets (Fig 6). The slight differences in longer-term mucosal zenith stability for the healed ridge group may reflect the well-known buccal bone resorption that occurs prominently at extraction sockets and the longer-term bone and connective tissue remodeling that has not yet been carefully evaluated. It remains unclear whether these minor changes are 3 y 5 y self-limiting. Concerning lifelong stability, 10- to 20- year data are presently not available. In addition, the relative location of the mucosal zenith is altered by other phenomena, such as adjacent tooth extrusion that occurs adjacent to single-tooth implants. With regard to interproximal tissue, De Rouck et al 20 concluded that management of papilla levels was predictable. The generally accepted notion that interproximal tissue levels are related to adjacent tooth connective tissue contacts and bone levels may explain much of this predictability. More detailed evaluation of both the contact point bone distance and the implant-tooth distance indicated the potential for this implant design to provide for full interproximal papillae. 31 Systematic reviews have further suggested that maintaining the midfacial gingival margin is less predictable and implicate postextraction bone remodeling as a factor affecting this parameter. 20 They suggest an average midfacial recession of 0.55 to 0.75 mm after 1 year. In the current 5-year report, the absence of midfacial recession was notable. In a retrospective evaluation 4 and in a 3-year prospective evaluation of an early loading protocol using the same dental implant system, 21,32 similar soft tissue stability at anterior single-tooth implants was reported. The current findings contrast with other reports concerning the immediate placement and provisionalization of dental implants, which have observed changes in peri-implant mucosal architecture following immediate loading, including midfacial recession (reviewed by Cooper et al 22 ). Many factors are implicated in this midfacial recession, 33 and further systematic evaluations of the important details that control this are needed. Whereas current investigations have used the Pink Esthetic Score and White Esthetic Score to evaluate peri-implant and implant crown esthetics, these evaluation methods were not introduced prior to the 1-year data collection period of this investigation. In addition, the relative risk of screw versus cement retention for restorations is now of current interest 34 with regard to peri-implant inflammation. The current investigation used cemented crowns, without remarkable biologic complications. The present data demonstrate that the illustrated combination of procedures and components resulted in only minor vertical midfacial mucosal changes among the selected population during the 5-year evaluation period. Conclusion This prospective evaluation revealed no differences in the hard and soft tissue levels 5 years after the immediate provisionalization of dental implants in extraction sockets or healed ridges. During this period, the marginal bone levels and soft tissue levels remained 716 Volume 29, Number 3, 2014

9 in close approximation to the implant/abutment interface and the prosthetic reference (mucosal zenith), respectively. Tissue architecture was stable throughout the investigation period. This midterm evaluation of the higher risk approach for tooth replacement involving immediate placement and provisionalization indicates that success can be attained using appropriate guidelines and with proper patient selection. AcknowledgmentS This study was supported by DENTSPLY Implants (formerly Astra Tech). The authors reported no conflict of interest related to this study. References 1. Pjetursson BE, Lang NP. Prosthetic treatment planning on the basis of scientific evidence. J Oral Rehabil 2008;35(suppl 1): den Hartog L, Slater JJ, Vissink A, Meijer HJ, Raghoebar GM. Treatment outcome of immediate, early and conventional single-tooth implants in the aesthetic zone: A systematic review to survival, bone level, soft-tissue, aesthetics and patient satisfaction. 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