Immediate single‐tooth implant placement in bony defect sites: A 10‐year randomized controlled trial

Abstract

Background

It is unclear whether an intact buccal bony plate is a prerequisite for immediate implant placement in postextraction sockets. The aim of this 10‐year randomized controlled trial was to compare peri‐implant soft and hard tissue parameters, esthetic ratings of, and patient‐reported satisfaction with immediate implant placement in postextraction sockets with buccal bony defects ≥5 mm in the esthetic zone versus delayed implant placement after alveolar ridge preservation.

Methods

Patients presenting a failing tooth in the esthetic region and a buccal bony defect ≥5 mm after an extraction were randomly assigned to immediate (Immediate Group, n = 20) or delayed (Delayed Group, n = 20) implant placement. The second‐stage surgery and provisional restoration placement occurred 3 months after implant placement in both groups, followed by definitive restorations 3 months thereafter. During a 10‐year follow‐up period, marginal bone levels (primary outcome), buccal bone thickness, soft tissue parameters, esthetics, and patient‐reported satisfaction were recorded.

Results

The mean marginal bone level change was −0.71 ± 0.59 mm and −0.36 ± 0.39 mm in the Immediate Group and the Delayed Group after 10 years (p = 0.063), respectively. The secondary outcomes were not significantly different between both groups.

Conclusions

Marginal bone level changes, buccal bone thickness, clinical outcomes, esthetics, and patients’ satisfaction following immediate implant placement, in combination with bone augmentation in postextraction sockets with buccal bony defects ≥5 mm, were not statistically different to those following delayed implant placement after ridge preservation in the esthetic zone.

Plain language summary

Immediate implant placement in case of a failing tooth is a favorable treatment option for patients because it considerably shortens treatment time and the number of surgical treatments. The question is if an intact buccal bone wall is necessary for immediate implant placement. A 10‐year study was performed in which 20 patients with a failing tooth in the frontal region of the upper jaw were treated with immediate implant placement and were compared with 20 patients in whom a more conventional treatment strategy was followed in which the failing tooth was first removed and the bone gap restored and the implant placed in a second step. After a 10‐year follow‐up period, it appeared that the bone around the implant was very stable, gums were healthy, and patients were very satisfied with the result. There was no difference between the two treatment procedures. Such results mean that professionals can discuss the procedure with the patient and apply the individual's preference.

1. INTRODUCTION

Immediate implant placement in the esthetic zone is a favorable treatment option if there is an intact buccal bone wall. ¹ , ² , ³ , ⁴ , ⁵ Some authors state that a compromised alveolar socket might affect the outcome of immediate implant placement. ¹ , ⁶ , ⁷ Therefore these authors recommend delayed implant placement combined with bone grafting and/or soft tissue grafting when a buccal plate defect is found at implant placement. ¹ , ⁶ , ⁷ However, there is some evidence that favorable treatment outcomes are also possible on placing implants directly in compromised postextraction sockets, although the included studies were not limited to the maxillary esthetic region. ⁸

There is very little literature on immediate implant placement in extraction sockets with a buccal plate defect in the maxillary esthetic region. Sarnachiaro et al., ⁹ Liu et al., ¹⁰ Pohl et al., ¹¹ Mizuno et al., ¹² and Qian et al. ¹³ performed prospective studies with a follow‐up of up to 1 year. Noelken et al. ¹⁴ studied immediate implant placement in patients with a buccal bone defect, with a median follow‐up of 22 months. Only Kamperos et al., ¹⁵ Slagter et al., ¹⁶ and Zhao et al. ¹⁷ reported 5‐year results for immediate implant placement in buccal defect sites. No long‐term studies with a follow‐up of at least 10 years have been published yet on this specific dental implant treatment.

Although it might not be essential to have an intact buccal plate at immediate implant placement, stable buccal bone thickness (BBT) and midbuccal mucosa levels are important long‐term parameters in the esthetic region. The BBT and midbuccal mucosa level should, preferably, be part of the evaluation, starting with preoperative measurements at baseline. ¹⁸ Only Liu et al., ¹⁰ Slagter et al., ¹⁶ Mizuno et al., ¹² Qian et al., ¹³ and Zhao et al. ¹⁷ assessed BBT and midbuccal mucosa levels in patients with buccal plate defects. It is important that studies performing immediate implant placement in compromised sites in the maxillary esthetic region report full‐scale evaluation parameters, including information on the buccal mucosa, bone level, and bone thickness. Medium‐term and long‐term follow‐ups are particularly needed (statements from the XV European Workshop in Periodontology). ¹⁹

Since full‐scale long‐term evaluations of implants inserted in postextraction sockets with buccal plate defects in the maxillary esthetic region are lacking, we undertook this 10‐year randomized controlled trial to assess changes in bone level, mucosa level, BBT, esthetic ratings by professionals, and patient‐reported satisfaction after immediate implant placement in postextraction sockets with buccal bony defects and delayed implant placement after ridge preservation in the esthetic region.

2. MATERIALS AND METHODS

2.1. Study design

Details of the study design, inclusion criteria, exclusion criteria, sample size calculation, patient characteristics, and 1‐ and 5‐year results were described by Slagter et al. in 2016 and Slagter et al. in 2021. ¹⁶ , ²⁰ The initial study was set up as a 1‐year randomized controlled trial. The Medical Ethical Committee (METc) of the University Medical Center Groningen (UMCG), the Netherlands, gave their consent for the 1‐year randomized controlled trial (NL32240.042.10). As the 10‐year follow‐up visit was part of a regular control appointment and did not serve to collect additional data, except for a questionnaire to be filled in by the participants, the METc concluded that it was not new clinical research involving test subjects, as referred to in the Medical Research Involving Human Subjects Act (METc UMCG RR number 202100181). The 1‐ and 10‐year studies were registered in the ISRCTN (International Standard Registered Clinical/Social Study Number) registry and the Dutch Trial Register, with the respective numbers ISRCTN57251089 and NTR_NL‐9340. All the patients gave written informed consent before enrollment and verbally approved the use of the research data obtained during the follow‐up. The study was conducted in accordance with the 2013 revised Helsinki Declaration of 1975. ²¹

Preoperatively, cone beam computed tomography (CBCT) was used to assess whether there was sufficient bone on the palatal side to place an implant since, for primary stability of the implant, sufficient palatal bone is necessary in case of labial dehiscence. The vertical bony defect had to be ≥5 mm at the labial socket wall after removal of the tooth.

Forty patients were enrolled and allocated to either

1. an Immediate Group (test group): immediate implant placement and delayed provisionalization or

2. a Delayed Group (control group): delayed implant placement after ridge preservation and delayed provisionalization.

2.2. Surgical procedure

The surgical procedure has been described in detail by Slagter et al. ²⁰ In short, both groups’ failing tooth in the maxillary esthetic region was carefully removed and a bone graft was harvested from the tuberosity region with the use of chisels. In all cases, the ailing tooth was removed with a sulcular incision, careful detachment of the periodontal ligament, and use of periotomes. After removal of the tooth, the alveolus was meticulously cleansed, and any alveolar debridement was removed. Preparation of the Immediate Group's alveolus was done at the palatal side guided by a surgical template for ideal positioning. The tuberosity bone graft was shaped with forceps to match the labial bony defect. The bone graft was placed in the extraction socket, with the cortical side facing the periosteum, under the periosteum covering the labial plate defect. A mixture of tuberosity bone and deproteinized bovine bone substitute (Bio‐Oss; Geistlich, Wolhusen, Switzerland) was used to fill the remaining space between the last bur and the tuberosity bone graft. In the Immediate Group, the implant site was prepared on the palatal side of the alveolus without raising a flap using a surgical template for ideal positioning. After this, a tapered dental implant (NobelActive; Nobel Biocare AB, Gothenburg, Sweden) was placed. A soft tissue graft, also from the tuberosity region, was placed to seal the implant site. ²² Three months later, the implant was uncovered and an implant‐level impression was made to manufacture a provisional restoration. The Delayed Group's alveolus was augmented with the same procedure described for the Immediate Group, but without implant placement. Three months after ridge preservation, a pedicled mucoperiosteal flap was raised in the Delayed Group to expose the maxilla, after which the tapered dental implant (NobelActive; Nobel Biocare AB, Gothenburg, Sweden) was placed using a surgical template. Three months after that, the implant was uncovered. The surgical procedures were performed by one experienced oral and maxillofacial surgeon (G.M.R.).

2.3. Prosthetic procedure

In both groups, a screw‐retained provisional restoration was placed on the same day that the implant was uncovered. After 3 months, porcelain‐fused‐to‐zirconia definitive crowns were manufactured for both groups. The restoration was either glass‐ionomer cement‐retained or screw‐retained. The abutment screws were torqued at 32 Ncm. The prosthetic procedures were performed by a single dental laboratory and one experienced prosthodontist (H.J.A.M.).

2.4. Outcome measures

The outcome measures have been described in detail by Slagter et al. ¹⁶ Change in marginal bone level (MBL) was the primary outcome. The following outcome items were evaluated:

2.4.1. MBL and BBT

Standardized digital periapical radiographs were made immediately after implant placement (baseline = T0) and 1 (T1) and 120 (T120) months after definitive restoration placement. ²³ Changes in MBL were calculated at T1 and T120 in relation to the level at baseline.

BBT measurements were done using 3D image diagnostic and treatment planning software (NobelClinician version 2.1; Nobel Biocare Guided Surgery Center, Mechelen, Belgium). Of each patient, the position of the implant was determined by importing the 1‐month and 10‐year CBCT, in DICOM multifile format, into an image computing program (Maxilim version 2.3; Medicim, Sint‐Niklass, Belgium). In NobelClinician, the exact position of the implant, as determined in Maxilim, was aligned with a planning implant. A slightly different procedure was followed for the pretreatment CBCT in which no implant was present. Both the pretreatment CBCT and the 1‐month CBCT were imported in Maxilim. Both images were aligned by the computing program. Because the exact position of the implant was determined for the 1‐month image, it was now possible to implement this position in the pretreatment DICOM file. In this way, a combined file was constructed in which the tooth was still present, and an implant was imported in the exact position where it was going to be after treatment. In fact, the measured distance on the pretreatment CBCT is the distance of the labial surface of the bony layer (if present) to the future implant. The upper 5‐mm section of the implant, starting at the implant neck toward the apical point, was defined as the area of interest (locations M1, M2, M3, M4, M5). Details of the methods for analyzing BBT can be found in Maes et al. and Slagter et al. ²⁴ , ²⁵

2.4.2. Survival rate

The implant and restoration survival rates were defined as the percentage still in function 10 years after implant placement.

2.4.3. Changes in interproximal and midbuccal peri‐implant mucosa levels

Standardized digital photographs were taken before extraction of the failing tooth (Tpre) and after 1 month (T1) and 120 months (T120), following the technique published by Meijndert et al. ²³ The interproximal and midbuccal changes were compared with the original gingival level of the failing tooth.

2.4.4. Clinical outcomes

Clinical variables assessed at Tpre, T1, and T120 were papilla volume, ²⁶ amount of plaque, ²⁷ amount of bleeding, ²⁷ gingival index, ²⁸ and probing pocket depth.

2.4.5. Esthetic assessment

Esthetic outcome (pink esthetic score/white esthetic score [PES/WES]) was assessed from the digital photographs. ²⁹

2.4.6. Patient satisfaction

Overall patient satisfaction was assessed by means of a visual analogue scale (VAS), with the possible scores ranging from 0 (completely dissatisfied) to 100 (completely satisfied).

2.4.7. Biological and technical complications

Biological complications, namely, peri‐implant mucositis and peri‐implantitis, were calculated according to the consensus reached at the 2017 World Workshop of the American Academy of Periodontology and European Federation of Periodontology, where peri‐implant mucositis (radiographic bone loss <2 mm) is bleeding on probing+ (BoP+) and/or suppuration, and peri‐implantitis is BoP+ and/or suppuration in combination with a marginal bone loss ≥2 mm. ³⁰ , ³¹ , ³² In addition to the kind and number of technical complications, the restoration success rate was also calculated up to the 10‐year follow‐up visit and assessed using the modified criteria of the United States Public Health Service (USPHS). ³³

2.5. Statistical analysis

A radiographic change in marginal bone loss of >0.9 mm (SD 1 mm) after 12 months of definitive crown placement was regarded as a relevant difference between study groups. With an expected effect size of 0.9 mm, an α of 0.05, and a power of 0.80, 38 patients were required—19 in each group. The primary analyses were performed per protocol strategy. The distribution of the continuous data was checked visually on histograms and was supplemented by the Shapiro–Wilk test and Q–Q plots. Normally distributed data have been reported here as means with 95% CI and compared between groups by using the independent sample t test. Non‐normally distributed variables have been reported as medians and interquartile ranges (first quartile to third quartile) and compared between groups with the Mann–Whitney U test.

In addition to the primary analyses, several sensitivity analyses were performed. First, the intention‐to‐treat strategy was applied to the primary outcome. Here, we considered the last‐observation‐carried‐forward, best–worst‐scenario (+1 and −1SD), and worst–best‐scenario (−1 and +1SD) methods as appropriate. Furthermore, since some of the outcomes consisted of repeated measurements, multivariable linear mixed‐effect models (LMM) were fitted using restricted maximum likelihood estimations to assess the between‐group differences of these repeated measurements (i.e., including the fixed effects of the type of intervention, baseline outcome measurement and follow‐up in months, and the random effect of patients). Effect estimates of each group at specific timepoints, including corresponding p values, were derived by centering the follow‐up variable for each specific timepoint. Both sensitivity analyses showed no substantial differences with the primary analyses (data available on request). Therefore, the primary analyses were shown to be robust and could thus be regarded as the main analyses.

The statistical analyses were performed in R version 4.0.5 (R Core team), using the lme4 and lmertest‐packages. In all the analyses, a p value <0.05 was considered as statistically significant.

3. RESULTS

3.1. Patients

Twenty patients were included in both the Immediate Group (mean age 44 ± 14 years) and the Delayed Group (mean age 49 ± 16 years). All the patients were treated accordingly. At the 10‐year evaluation, 15 Immediate‐Group patients (2 patients had died, 2 patients had moved, and 1 patient had changed their upper dentition into an implant‐supported overdenture) and 15 Delayed‐Group patients (4 patients had died and 1 patient had lost the implant) were available (Figure 1).

FIGURE 1.

CONSORT flow diagram.

3.2. Changes in MBL and BBT

Table 1 shows the mean MBL changes at the approximal sites separately and of the approximal sites combined (mean change at the mesial and distal side). The largest MBL change occurred in the period from implant placement until T1 in both groups. After 10 years with the definitive restoration, only minor changes were observed in both groups, without significant differences between the groups (Immediate Group [−0.71 mm; 95% CI, −1.04 to −0.38] vs. Delayed Group [−0.36 mm; 95% CI, −0.58 to −0.14], p = 0.063).

TABLE 1.

Changes in marginal bone level from implant placement (baseline) to 1 month (T1) and to 120 months (T120) and changes in marginal soft tissue level from preoperative (Tpre) to 1 month (T1) and to 120 months (T120) after definitive crown placement.

	T1	T1		T120	T120
	Mean (95% CI)	Mean (95% CI)		Mean (95% CI)	Mean (95% CI)
Variable	Immediate	Delayed	p value a	Immediate	Delayed	p value a
Marginal bone level changes in mm (95% CI)
Mesial of implant	−0.44 (−0.62 to −0.26)	−0.49 (−0.68 to −0.30)	0.692	−0.63 (−0.98 to −0.28)	−0.36 (−0.58 to −0.14)	0.181
Distal of implant	−0.66 (−0.88 to −0.44)	−0.52 (−0.74 to −0.30)	0.342	−0.80 (−1.13 to −0.47)	−0.35 (−0.58 to −0.12)	0.025
Mesial and distal side	−0.55 (−0.71 to −0.39)	−0.51 (−0.69 to −0.33)	0.692	−0.71 (−1.04 to −0.38)	−0.36 (−0.58 to −0.14)	0.063
Marginal soft tissue level changes in mm (95% CI)
Mesial of implant	−0.15 (−0.23 to −0.07)	−0.16 (−0.23 to −0.09)	0.790	−0.26 (−0.66 to 0.14)	−0.48 (−0.93 to −0.03)	0.449
Distal of implant	−0.18 (−0.28 to −0.08)	−0.22 (−0.30 to −0.14)	0.460	−0.38 (−0.85 to 0.09)	−0.66 (−1.23 to −0.09)	0.431
Midfacial of implant	−0.13 (−0.26 to 0.00)	−0.30 (−0.52 to −0.08)	0.188	−0.24 (−0.67 to 0.19)	−0.19 (−0.49 to 0.11)	0.843

^a Independent sample t test.

BBT (in medians and interquartile ranges) for the M0 to M5 levels are depicted in Table 2. The preoperative CBCT scan analyses revealed no significant differences between the groups at all six positions. At the 10‐year evaluation, there were no significant differences in BBT between the groups at all six positions.

TABLE 2.

Buccal bone thickness preoperative and 1 month and 10 years after definitive restoration placement in Immediate group (immediate placement/delayed provisionalization) and Delayed group (delayed placement/delayed provisionalization), expressed as medians with 25th–75th percentile and corresponding p values between the two groups.

	Immediate	Delayed
Buccal bone thickness preoperative	Median (interquartile range) in mm	Median (interquartile range) in mm	p value a
M0 (at neck)	0.00 [0.00; 0.00]	0.00 [0.00; 0.00]	> 0.999
M1	0.00 [0.00; 0.00]	0.00 [0.00; 0.00]	> 0.999
M2	0.00 [0.00; 0.00]	0.00 [0.00; 0.00]	> 0.999
M3	0.00 [0.00; 0.00]	0.00 [0.00; 0.00]	> 0.999
M4	0.00 [0.00; 0.49]	0.00 [0.00; 0.00]	0.616
M5	0.00 [0.00; 1.44]	0.00 [0.00; 0.74]	0.477
Buccal bone thickness 1 month
M0 (at neck)	0.91 [0.76; 1.22]	0.64 [0.54; 0.74]	0.001
M1	1.16 [0.70; 1.81]	0.56 [0.46; 1.13]	0.007
M2	1.14 [0.69; 1.58]	0.65 [0.48; 1.36]	0.076
M3	1.25 [0.77; 1.73]	0.64 [0.45; 1.43]	0.046
M4	1.04 [0.74; 1.73]	0.60 [0.28; 1.31]	0.037
M5	0.89 [0.57; 1.64]	0.51 [0.26; 1.22]	0.077
Buccal bone thickness 10 years
M0 (at neck)	1.24 [0.63; 1.53]	1.04 [0.44; 1.44]	0.442
M1	1.63 [1.33; 1.86]	1.46 [0.86; 1.83]	0.505
M2	1.57 [1.27; 1.77]	1.27 [0.77; 1.53]	0.108
M3	1.43 [1.13; 1.95]	1.35 [1.05; 1.83]	0.616
M4	1.53 [1.05; 1.83]	1.25 [0.65; 1.93]	0.442
M5	1.36 [0.76; 1.94]	1.26 [0.66; 1.56]	0.573

^a Mann–Whitney U test.

3.3. Survival rate

No implants were lost in the Immediate Group and one implant was lost in the Delayed Group (after 6 years in function), resulting in an implant survival rate of 100% and 93.8%, respectively. One restoration was lost in the Immediate Group after 8 years in function and one restoration was lost in the Delayed Group because the implant had been lost, resulting in a restoration survival rate of 93.3% and 93.8%, respectively.

3.4. Changes in interproximal and midbuccal peri‐implant mucosa levels

Changes in soft tissue levels from preoperative to 10 years after placing the definitive restorations are shown in Table 1. The 10‐year midbuccal mucosa level changes were −0.24 mm (95% CI, −0.67 to 0.19) and −0.19 mm (95% CI, −0.49 to 0.11) in the Immediate Group and Delayed Group, respectively. Hence the difference was not significant (p = 0.843).

3.5. Clinical outcomes

In both groups, low plaque and bleeding indexes and a healthy peri‐implant mucosa were observed, with no significant differences between the groups (Table 3). Also, the pocket probing depths were stable throughout the evaluation period, without significant group differences (Table 3).

TABLE 3.

Preoperative (Tpre) and 1 month (T1) and 120 months (T120) clinical outcome measures (papilla index, gingival index, plaque index, bleeding index, and pocket probing depth), esthetic evaluation, and overall patient satisfaction.

	Tpre			T1			T120
Variable	Immediate	Delayed	p value a	Immediate	Delayed	p value a	Immediate	Delayed	p value a
Papilla volume (papilla index; median [IQR])
Mesial	2.5 [1.0; 3.0]	2.0 [1.0; 3.0]	0.369	2.5 [1.0; 3.0]	2.0 [1.0; 3.0]	0.309	3.0 [2.0; 3.0]	2.0 [1.0; 3.0]	0.209
Distal	2.0 [1.0; 3.0]	2.0 [1.0; 3.0]	0.732	2.0 [1.0; 3.0]	2.0 [1.0; 3.0]	0.132	2.0 [2.0; 2.0]	2.0 [2.0; 2.0]	0.758
Health of gingiva (gingival index; median [IQR])	0.0 [0.0; 0.0]	0.0 [0.0; 0.0]	0.487	0.0 [0.0; 0.0]	0.0 [0.0; 0.0]	>0.999	0.0 [0.0; 0.0]	0.0 [0.0; 0.0]	>0.999
Amount of plaque (plaque index; median [IQR])	0.00 [0.0; 0.0]	0.0 [0.0; 0.0]	>0.999	0.0 [0.0; 0.0]	0.0 [0.0; 0.0]	>0.999	0.0 [0.0; 0.0]	0.0 [0.0; 0.0]	>0.999
Bleeding after probing (bleeding index; median [IQR])	1.0 [0.0; 1.0]	1.0 [0.0; 1.8]	0.494	0.0 [0.0; 1.0]	0.0 [0.0; 1.0]	0.773	0.0 [0.0; 0.0]	0.0 [0.0; 0.0]	>0.999
Pocket probing depth (mm; mean [95% CI])
Mesial	2.90 (2.17–3.63)	3.30 (2.54–4.06)	0.431	3.15 (2.87–3.43)	3.15 (2.84–3.46)	>0.999	2.73 (2.34–3.12)	2.53 (2.07–2.99)	0.484
Distal	3.25 (2.77–3.73)	3.45 (2.73–4.17)	0.631	3.60 (3.28–3.92)	3.25 (2.95–3.55)	0.102	2.60 (2.25–2.95)	2.80 (2.42–3.18)	0.410
Buccal	1.65 (1.30–2.00)	2.25 (1.73–2.77)	0.053	2.90 (2.53–3.27)	3.20 (2.78–3.62)	0.267	2.40 (2.05–2.75)	2.27 (2.02–2.52)	0.514
Palatal	2.15 (1.77–2.53)	3.05 (2.15–3.95)	0.066	2.80 (2.61–2.99)	2.85 (2.57–3.13)	0.757	2.27 (1.88–2.66)	2.20 (1.97–2.43)	0.754
Esthetic evaluation (mean [95% CI])
PES	6.10 (5.03–7.17)	6.35 (5.51–7.19)	0.702	6.55 (5.71–7.39)	6.20 (5.33–7.07)	0.547	7.40 (6.62–8.18)	6.93 (6.22–7.64)	0.350
WES	4.05 (2.76–5.34)	5.00 (3.77–6.23)	0.271	7.20 (6.68–7.72)	7.60 (7.07–8.13)	0.267	7.60 (6.85–8.35)	7.13 (6.38–7.88)	0.353
PES/WES	10.15 (8.23–12.07)	11.35 (9.88–12.82)	0.306	13.75 (12.69–14.81)	13.80 (12.87–14.73)	0.941	15.00 (13.87–16.13)	14.07 (12.95–15.19)	0.218
Overall patient satisfaction (score 0–100; mean [95% CI])	NA	NA	NA	79.4 (72.8–86.0)	80.7 (74.9–86.5)	0.758	86.7 (82.2–91.2)	88.5 (83.9–93.2)	0.556

Abbreviations: IQR, interquartile range; NA, not applicable; PES, pink esthetic score; WES, white esthetic score.

^a Mann–Whitney U test for papilla, gingiva, plaque, and bleeding indexes; independent sample t test for pocket probing depth, esthetic evaluation, and patient satisfaction.

3.6. Esthetic assessment

Both groups’ PES/WES were acceptable throughout the follow‐up (Table 3). The total esthetic outcome was 15.0 (95% CI, 13.87–16.13) in the Immediate Group and 14.07 (95% CI, 12.95–15.19) in the Delayed Group (p = 0.218).

3.7. Patient satisfaction

Overall patient satisfaction (Table 3) was high and not statistically different between the groups throughout the follow‐up (p = 0.556).

3.8. Biological and technical complications

The incidence of peri‐implant mucositis was 20.0% in both the Immediate Group and the Delayed Group, hence the difference between the groups was not significant (p > 0.999). None of the patients in either group developed peri‐implantitis.

In the Immediate Group, a new restoration was made for one patient due to fracture and one patient experienced decementation of the restoration from the abutment (this crown could be cemented again). In the Delayed Group, a new restoration had to be made for one patient because of inserting a new implant and porcelain chipping was seen in two patients (this complication could be solved by polishing, without the need for a new restoration). The restoration success, assessed according to the modified USPHS criteria, ³³ is shown in Table 4. The calculated restoration success rate was 86.6% in the Immediate Group and 93.3% in the Delayed Group.

TABLE 4.

Modified United States Public Health Service (USPHS) criteria ³³ for evaluating implant‐supported restorations at 10‐year follow‐up.

	Alfa (A)		Bravo (B)		Charlie (C)		Delta (D)
	Group Immediate	Group Delayed	Group Immediate	Group Delayed	Group Immediate	Group Delayed	Group Immediate	Group Delayed
Restoration fracture	Restoration not fractured 14 (93.3%)	Restoration not fractured 13 (86.7%)	Chipping, but polishing possible 0 (0%)	Chipping, but polishing possible 2 (13.3%)	Chipping down to abutment 0 (0%)	Chipping down to abutment 0 (0%)	Restoration fractured, new restoration needed 1 (6.7%)	Restoration fractured, new restoration needed 0 (0%)
Abutment fracture	Abutment not fractured 15 (100%)	Abutment not fractured 15 (100%)	–	–	–	–	Abutment fractured, new restoration needed 0 (0%)	Abutment fractured, new restoration needed 0 (0%)
Loosening of restoration (screw loosening or decementation from abutment)	No loosening 14 (93.3%)	No loosening 15 (100%)	–	–	Repositioning possible 1 (6.7%)	Repositioning possible 0 (0%)	Repositioning not possible, new restoration needed 0 (0%)	Repositioning not possible, new restoration needed 0 (0%)
Screw‐access hole restoration	Restoration not lost 15 (100%)	Restoration not lost 15 (100%)	–	–	Restoration lost (repairable) 0 (0%)	Restoration lost (repairable) 0 (0%)	–	–
Wear	No wear facets on restoration and opposing teeth 15 (100%)	No wear facets on restoration and opposing teeth 15 (100%)	Small wear facets (diameter <2 mm) on restoration and/or opposing teeth 0 (0%)	Small wear facets (diameter <2 mm) on restoration and/or opposing teeth 0 (0%)	Wear facets (diameter >2 mm) on restoration and/or opposing teeth 0 (0%)	Wear facets (diameter >2 mm) on restoration and/or opposing teeth 0 (0%)	–	–
Anatomical shape	Ideal anatomical shape, tight proximal contacts, and balanced occlusal contact 15 (100%)	Ideal anatomical shape, tight proximal contacts, and balanced occlusal contact 15 (100%)	Slightly over‐ or undercontoured, weak proximal contacts, occlusal contact only on restoration 0 (0%)	Slightly over‐ or undercontoured, weak proximal contacts, occlusal contact only on restoration 0 (0%)	Highly over‐ or undercontoured, open proximal contacts, no occlusal contact on restoration 0 (0%)	Highly over‐ or undercontoured, open proximal contacts, no occlusal contact on restoration 0 (0%)	–	–
Restoration color and translucency	No mismatch between restoration and adjacent teeth 2 (13.3%)	No mismatch between restoration and adjacent teeth 4 (26.7%)	Slight mismatch between restoration and adjacent teeth 13 (86.7%)	Slight mismatch between restoration and adjacent teeth 10 (66.6%)	Major mismatch between restoration and adjacent teeth 0 (0%)	Major mismatch between restoration and adjacent teeth 1 (6.7%)	–	–
Cementation gap	No cementation gap visible on radiograph 15 (100%)	No cementation gap visible on radiograph 15 (100%)	Minor gap visible 0 (0%)	Minor gap visible 0 (0%)	Major gap visible, new restoration not needed 0 (0%)	Major gap visible, new restoration not needed 0 (0%)	Major gap visible, new restoration needed 0 (0%)	Major gap visible, new restoration needed 0 (0%)
Patient satisfaction	Very satisfied 15 (100%)	Very satisfied 15 (100%)	Moderately satisfied 0 (0%)	Moderately satisfied 0 (0%)	Not satisfied, new restoration not needed 0 (0%)	Not satisfied, new restoration not needed 0 (0%)	Not satisfied, new restoration needed 0 (0%)	Not satisfied, new restoration needed 0 (0%)
	Survival and success 0%	Survival and success 13.3%	Survival and success 86.6%	Survival and success 80.0%	Survival, no success 6.7%	Survival, no success 6.7%	Failure 6.7%	Failure 0%

4. DISCUSSION

Both immediate implant placement, in combination with a bone augmentation procedure, and delayed implant placement after ridge preservation in postextraction sockets with buccal bony defects ≥5 mm in the esthetic zone were accompanied by minor peri‐implant bone loss, good peri‐implant parameters and favorable patient satisfaction at the 10‐year evaluation, without significant differences between both procedures.

As far as we know, prospective studies reporting full‐scale outcomes with an evaluation period of at least 10 years after immediate dental implant placement in anterior maxillary sites with labial bony defects have not been published yet. Kamperos et al., ¹⁵ Slagter et al., ¹⁶ and Zhao et al. ¹⁷ analyzed immediate implant placement in buccal defect sites over 5 years. However, it must be mentioned that Slagter et al. ¹⁶ reported results from the same study group as the present study. Therefore, it would be best to compare the results of our test group with the retrospective studies by Kamperos et al. ¹⁵ and Zhao et al. ¹⁷ that dealt with immediate implant placement and esthetic and radiographic outcomes at 5 years, and the results of the control group with the 10‐year retrospective study by Iorio‐Siciliano et al., ³⁴ which examined delayed implant placement after alveolar ridge preservation. The Kamperos et al. ¹⁵ study only evaluated PES values (possible total score 0–14) and reported a 9.5 PES and a 9.6 PES for the immediate‐ and delayed implant placement groups, respectively. In the present study, the PES values (possible total score 0–10) were 7.4 and 6.9, respectively. Taking the different total possible scores into account, it can be concluded that the PES results are in line with the other study. The 5‐year Zhao et al. ¹⁷ study only evaluated radiographic outcomes and PES values from an immediate implant placement group. They reported a mean peri‐implant bone loss of 0.71 and 0.73 mm at the mesial and distal side of the implant, respectively. Again, these figures are in line with our study's results. Zhao et al. ¹⁷ also assessed BBT and reported a mean BBT of 2.86 mm at the end of the 5‐year evaluation period, whereas the present study's median 10‐year BBT varied from 1.24 to 1.63 mm. This difference in BBT can be explained by the fact that Zhao et al. ¹⁷ augmented the defect more extensively, resulting in an initially higher BBT. Comparatively, both studies’ change in BBT was limited. Regarding PES values, Zhao et al. ¹⁷ results’ were higher, which might be due to their more extensive augmentation procedure. Iorio‐Siciliano et al. ³⁴ performed a 10‐year retrospective study of dental implants after alveolar ridge preservation. A provisional restoration was connected 3–6 months after implant placement; the definitive restorations were placed 3 months later. The implant survival rate was high, thus comparable to the present study. A mean peri‐implant bone loss of 1.1 and 1.0 mm at the mesial and distal side of the implant, respectively, was reported by the other authors; it was even more limited in our study. Thus, both studies show limited bone loss after 10 years.

It is striking that not only are there no long‐term studies available comparing implant treatment options for extraction sockets with a buccal bone defect but also that there is a scarcity of medium‐ to long‐term results of a single treatment option. Moreover, full‐scale evaluations, including information on buccal mucosa and buccal bone level and thickness, are missing. This also counts for patient‐reported outcomes and long‐term biological and technical complications, even though this was recommended by the XV European Workshop in Periodontology. ¹⁹

Midfacial soft tissue level (with underlying buccal bone presence), papilla volume/approximal soft tissue level (with sufficient mesial/distal bone level), and PES/WES are important parameters for determining esthetic treatment success. ³⁵ The midfacial soft tissue level appeared to be very stable in both groups throughout the 10‐year evaluation period. On analyzing the presence of underlying bone at the buccal side of the implant, one can see that both groups’ median BBT was more than 1 mm at the neck of the implant at the 10‐year evaluation timepoint. There was no significant difference between both groups in terms of these outcome parameters. Apparently, immediate implant placement in case of a buccal bony defect does not compromise the esthetic result at the midfacial implant side. Also, papilla volume/approximal soft tissue level and mesial/distal bone appeared to be very stable in both groups throughout the 10‐year evaluation period, without a significant difference between the groups. Both treatment options led to sufficient PES/WES and satisfied patients at both the start of the evaluation (1 month after placement of the definitive restoration) and at the 10‐year evaluation timepoint. Buser et al. ³⁶ recommended a fully intact buccal bone wall with a thickness of at least 1 mm when considering immediate implant placement. Jung et al. ⁷ recommended delayed implant placement combined with a bone grafting and/or soft tissue grafting approach when a buccal bone defect is noted at implant placement. Possible risk factors for immediate placement in less favorable cases would be orofacial flattening of the soft tissue profile and recession of the facial mucosa. However, our results do not support these statements because of the favorable 10‐year outcomes after immediate implant placement combined with bone augmentation.

The biological and technical complications were limited in both groups. Derks and Tomasi ³⁷ published a systematic review in which a prevalence of 43% was mentioned for peri‐implant mucositis and 22% for peri‐implantitis. Fu and Wang ³⁸ and Roccuzzo et al. ³⁹ recently suggested that these high biological disease figures were mainly caused by wrong planning and surgical and prosthetic errors. Our study's biological disease values are much lower. The reason could be that only single‐tooth restorations were included in both study groups, which were carefully planned and could be easily cleaned, as apparent from the clinical outcome parameters. Also, the technical complications were limited in the present study, leading to a high restoration success rate calculated with the modified USPHS criteria. ³³ The Donker et al. ⁴⁰ 10‐year study had a similar high restoration success rate; they used the same criteria as well as the same implant system and restoration design.

Both procedures tested in the present study resulted in the same good bone and soft tissue outcomes, and the professionals and patients were equally satisfied. Such similar results mean that professionals can discuss the procedure with the patient and apply the individual's preference. Nevertheless, it must be mentioned that the procedure applied to the Immediate Group requires 3 months less treatment time than the Delayed Group.

Some limitations of the current study need to be mentioned. First, the initial group size calculation revealed that 19 patients would be necessary in each group. ²⁰ At the 10‐year evaluation, 15 patients could be analyzed from each group. The dropout rate (i.e., 5 patients in each treatment group) results in a higher probability of false‐negative findings (i.e., Type II error). A post hoc power calculation resulted in an achieved power of 72%. Therefore, the lack of statistical difference in the primary outcome (p = 0.063) might be due a false‐negative finding as a result of the lower power of the current analyses compared to the baseline sample size calculation. However, the power of the current analysis after 10‐year follow‐up of a randomized controlled trial is still considered high. In addition, the reasons for loss to follow‐up were mainly due to the death of subjects, which is very unlikely to be related to the intervention tested in the current manuscript. Furthermore, the dropout rates of both treatment arms are similar, which lowers the probability of bias due to loss to follow‐up. Thus, although loss to follow‐up is a common limitation in studies with a long‐term follow‐up, our study's results should be interpreted with some caution. Next, the study was carried out in a university setting. This means that highly experienced professionals treated the patients. Also, the participant selection process was strict. Hence, the results of our study may be different from those achieved by a general practice.

5. CONCLUSIONS

Despite the limitations, it can be concluded from this 10‐year evaluation that both immediate implant placement, in combination with a bone augmentation procedure, and implant placement 3 months after alveolar ridge preservation in postextraction sockets with buccal bony defects ≥5 mm in the esthetic region result in very favorable objective and subjective outcomes.

AUTHOR CONTRIBUTIONS

All the authors contributed substantially to the conception, design, data interpretation, and critical revision of the study and the manuscript, and approved the final version for publication. Henny J. A. Meijer and Kirsten W. Slagter were involved in collecting the data and drafting the manuscript. Henny J. A. Meijer and Barzi Gareb were involved in the data analysis.

CONFLICT OF INTEREST STATEMENT

The study was supported by an unrestricted grant from Nobel Biocare Services AG, Gothenburg, Sweden (by means of implant materials; research grant 2012‐1135). The authors report no conflicts of interest.

FUNDING INFORMATION

The authors received no specific funding for this work.

Meijer HJA, Slagter KW, Gareb B, Hentenaar DFM, Vissink A, Raghoebar GM. Immediate single‐tooth implant placement in bony defect sites: A 10‐year randomized controlled trial. J Periodontol. 2025;96:151–163. 10.1002/JPER.24-0251

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.