Periosteal Sutures Versus Titanium Tacks for Guided Bone Regeneration in the Aesthetic Zone: A Pilot Randomized Controlled Trial

1. Introduction

Guided bone regeneration depends on two fundamental biological conditions: 1. the creation of a stable compartment that protects the graft during early healing, and 2. the achievement of a tension-free soft-tissue closure capable of preserving that compartment throughout the regenerative phase [1,2]. To address these requirements, several surgical refinements have been introduced. Periosteal-releasing approaches, for example, enable controlled coronal advancement of the buccal flap while preserving its vascular supply, thereby facilitating tension-free primary closure and reducing the risk of membrane exposure [3]. Our group has previously standardized and reported one such technique, offering a reproducible method for flap advancement in sites with significant buccolingual atrophy [4].

A second key determinant of predictable augmentation is graft stabilization. Preclinical studies have demonstrated that membrane fixation enhances GBR outcomes by improving space maintenance and limiting graft micromotion, thereby promoting more favorable conditions for new bone formation [5,6]. Traditional fixation using titanium tacks or screws provides rigid immobilization but requires additional surgical steps and often necessitates hardware removal at re-entry. As a less invasive alternative, periosteal mattress suturing has been proposed as a hardware-free fixation method that stabilizes particulate or block grafts beneath the membrane through apical and lateral anchorage [7]. This technique has been shown to integrate efficiently into the workflow of lateral ridge augmentation [8].

Beyond flap management and fixation strategies, the biological characteristics of the graft material also play a central role in treatment predictability. Composite bone grafts such as xenogeneic blocks composed of deproteinized bovine mineral integrated within a collagen matrix offer both structural and handling advantages. The mineralized component provides a stable three-dimensional scaffold for new bone formation, while the collagen matrix enhances adaptability and facilitates intimate contact with the recipient site. This combination generates a malleable yet volumetrically stable graft that can support the regenerative process in lateral defects [9,10,11].

Because these three elements, adequate soft-tissue release, hardware-free graft stabilization, and composite graft materials address complementary aspects of the regenerative environment, their combined application may provide a biologically coherent alternative to titanium-tack fixation. The objective of the present study was therefore to compare postoperative buccal bone dimensions after implant placement between sites stabilized with titanium tacks and those stabilized with periosteal sutures.

2. Materials and Methods

2.1. Participants

All study procedures were conducted under approval of the Scientific Ethics Committee of the Servicio de Salud Aconcagua (CEC-SSA 19/2021) and in accordance with national regulations. Patients were consecutively recruited from the Periodontics Clinic of Hospital San Camilo, where individuals seeking implant therapy in the anterior maxilla were screened for eligibility. Those requiring simultaneous guided bone regeneration at the time of implant placement were evaluated by the clinical team, and candidates meeting the inclusion criteria were invited to participate. A trained investigator not involved in the surgical treatment provided verbal and written information regarding the study objectives and procedures, obtained written informed consent in the presence of an authorized witness, and ensured that participation was voluntary and could be discontinued at any time.

A total of 46 patients seeking implant therapy in the anterior maxilla were assessed for eligibility. Of these, 6 patients were excluded prior to enrollment due to uncontrolled diabetes (n = 4) or ongoing bisphosphonate therapy (n = 2). The remaining 40 patients met the inclusion criteria, provided informed consent, and were randomized. Nineteen patients were allocated to the suture fixation group, of whom 17 received the allocated intervention, while 2 declined treatment. Twenty-one patients were allocated to the titanium tack fixation group, of whom 20 received the allocated intervention and 1 declined treatment. During the follow-up period, in the tack fixation group, 3 patients were lost to follow-up after declining continued participation and abandoning treatment, and 1 implant failure was recorded, resulting in 16 patients completing the six-month follow-up. In the suture fixation group, 1 patient was lost to follow-up after declining continued participation, and 16 patients completed follow-up. For radiographic analysis, 2 cases in the tack fixation group were excluded due to radiographic artifacts, resulting in 14 implants analyzed in this group, whereas all 16 cases in the suture fixation group were included in the final analysis. The overall flow of participants through enrollment, allocation, follow-up, and analysis is summarized in the CONSORT diagram shown in Figure 1.

A full clinical and radiographic baseline examination was performed following consent. This included a cone-beam computed tomography scan (CBCT) obtained at an external radiology facility, as well as digital impressions.

Implant surgeries were performed by an experienced periodontist using a standardized approach, and guided bone regeneration was carried out simultaneously with implant placement. The postoperative course was uneventful for all participants, with no adverse events observed during early healing. Follow-up visits were scheduled at 7 and 14 days to assess soft tissue healing and remove sutures as appropriate, and an additional evaluation was performed at approximately four weeks, consistent with the institutional protocol for implant patients. Long-term healing was assessed at six months, at which time a second CBCT scan and digital impressions were obtained to allow quantitative and qualitative evaluation of the regenerated tissues.

All clinical data were collected by a calibrated periodontist who was not involved in the surgical procedures.

2.2. Study Design and Surgical Procedures

This study evaluated the dimensional characteristics of the buccal bone contour following implant placement and guided bone regeneration (GBR). All implants were placed in healed ridges following standard surgical protocols. Buccal augmentation was performed using a xenogeneic composite block graft of bovine origin, consisting of deproteinized bone particles embedded in a collagen matrix (InterOss^® Collagen Block, Sigmagraft). The block graft was shaped to the recipient site and positioned to restore the buccolingual contour and then covered by a resorbable collagen membrane (InterCollagen^® Guide, Sigmagraft).

Two different graft-stabilization approaches were compared following horizontal guided bone regeneration. In one group (T), the composite bovine block graft was secured using titanium tacks (Titan pin set^®, Botiss). In the second group (S), the graft was stabilized using the periosteal mattress suture technique as described in detail elsewhere [8]. Briefly, this method employs vertically oriented periosteal sutures placed to immobilize the graft laterally, supplemented by a horizontal mattress suture extending between the flap edges to prevent apical displacement. A schematic illustration of both stabilization approaches is shown in Figure 2. The soft tissues were advanced and closed without tension. A healing period of six months was allowed before further evaluation.

2.3. Radiographic Acquisition and Measurement Protocol

After six months, all participants underwent cone beam computed tomography (CBCT) using a standardized acquisition protocol. For each implant, three reference levels were identified: 1 mm, 3 mm, and 6 mm apical to the implant platform. At each of these levels, a perpendicular linear measurement was taken from the implant surface to the outer contour of the buccal bone. These measurements represented the horizontal bone thickness at each depth.

Implants were oriented in cross-sectional views to ensure a true buccolingual slice perpendicular to the long axis. All measurements were performed by a calibrated examiner using radiographic analysis software with a known spatial resolution (Blue Sky Plan^® version 4.7.55, BlueSky Bio).

To integrate information across depths, the buccal bone contour between 1 mm and 6 mm was reconstructed using three coordinate pairs corresponding to the horizontal bone thickness at 1 mm, 3 mm, and 6 mm below the platform. These values were treated as points along the long axis of the implant. Between these points, linear interpolation was used to construct a piecewise linear approximation of the buccal bone surface. The bone area covering the implant between 1 and 6 mm was then computed as the sum of two trapezoidal regions bounded by the implant surface (vertical reference line), the interpolated bone contour, and the perpendicular lines at 1 mm, 3 mm, and 6 mm. This generated a reproducible quantitative metric representing the buccal bone envelope in the augmented region (Figure 3).

Figure 3. Buccal bone profile and calculated bone area derived from CBCT measurements at 1, 3, and 6 mm.

Figure 3. Buccal bone profile and calculated bone area derived from CBCT measurements at 1, 3, and 6 mm.

2.4. Statistical Analysis

All statistical procedures were carried out using Python 3.11. Data organization and preliminary processing were conducted with the pandas library, numerical computations with numpy, and inferential testing with the scipy.stats module. Graphical evaluations of distributional patterns and internal verification steps were performed with matplotlib.

For each subject, horizontal bone measurements obtained at 1 mm, 3 mm, and 6 mm below the implant platform were treated as independent quantitative variables. In addition, a derived metric representing the total buccal bone area between 1 mm and 6 mm — calculated through the geometric combination of two trapezoidal regions based on the measured thicknesses — was included as an outcome of interest. To complement these values, the mean bone thickness across the three reference depths was also computed for each implant, and this mean value was compared between the two groups.

The normality of each variable in group T and group S was evaluated through the Shapiro–Wilk test. When both groups met the assumptions of normality, intergroup comparisons were performed using an independent-samples t-test with Welch’s correction. When the assumption of normality was violated in either group, the Mann–Whitney U test was used instead. This analytical approach was applied to the measurements at 1 mm, 3 mm, and 6 mm, to the reconstructed bone area, and to the mean of the three linear measurements, allowing a comprehensive evaluation of potential differences in buccal bone morphology between the two groups. A two-tailed significance threshold of p < 0.05 was adopted for all analyses.

3. Results

Descriptive statistics for all linear measurements, including horizontal bone thickness at 1 mm, 3 mm, and 6 mm below the implant platform as well as the mean thickness across these reference points, are presented in Table 1. The comparative analysis showed no statistically significant differences between group T and group S for any of the linear measurements. Both groups demonstrated similar central tendencies and overlapping dispersion ranges across all three depths, and the same pattern was observed when the combined mean thickness was evaluated (Figure 3).

Figure 3. Boxplots illustrate horizontal buccal bone thickness (mm) at different reference levels around implants augmented with a bovine composite block graft and stabilized either with titanium tacks (T) or periosteal sutures (S). (A) Thickness measured 1 mm apical to the implant platform. (B) Thickness measured 3 mm apical to the platform. (C) Thickness measured 6 mm apical to the platform. (D) Mean buccal bone thickness calculated from the measurements at 1-, 3- and 6-mm. T = tacks group; S = sutures group.

Figure 3. Boxplots illustrate horizontal buccal bone thickness (mm) at different reference levels around implants augmented with a bovine composite block graft and stabilized either with titanium tacks (T) or periosteal sutures (S). (A) Thickness measured 1 mm apical to the implant platform. (B) Thickness measured 3 mm apical to the platform. (C) Thickness measured 6 mm apical to the platform. (D) Mean buccal bone thickness calculated from the measurements at 1-, 3- and 6-mm. T = tacks group; S = sutures group.

The reconstructed buccal bone area calculated between 1 mm and 6 mm, derived from the trapezoidal integration of the horizontal measurements, also showed no significant differences between groups. The distributions of area values were broadly comparable, reflecting similar postoperative buccal bone envelopes regardless of stabilization method. These results are presented in Figure 4, which displays the boxplot of the total area for the two groups.

4. Discussion

The present RCT showed that periosteal mattress sutures achieved buccal bone regeneration outcomes similar to titanium tacks when used to stabilize a composite xenogeneic block graft during simultaneous implant placement. Horizontal bone thickness at 1 mm, 3 mm, and 6 mm below the implant platform, as well as the reconstructed buccal bone area between these levels, showed no significant differences between groups.

These findings indicate that, under controlled surgical conditions and when combined with appropriate flap management, suture-based stabilization may maintain the regenerative compartment as effectively as conventional hardware fixation. This observation is consistent with previous reports suggesting that the mechanical stability required for guided bone regeneration can be achieved without rigid fixation devices [12].

The present findings might be explained by the following reasons. Titanium tacks are traditionally used to immobilize grafts and membranes, reducing micromotion and preserving the augmented space during early healing. However, stable flap closure and adequate soft-tissue adaptation are also critical contributors to compartment maintenance. Periosteal mattress suturing aims to reproduce the stabilizing effect of rigid fixation by anchoring the graft and membrane apically and laterally, thereby restricting displacement while avoiding the need for a second surgical intervention for hardware removal. Previous descriptions of periosteal sutures have highlighted their potential to provide hardware-free stabilization in lateral ridge augmentation, and the present results add quantitative radiographic evidence supporting their clinical utility.

The use of a composite xenogeneic block graft, consisting of deproteinized bovine mineral integrated within a collagen matrix, may also have contributed to the comparable outcomes observed in both groups. Composite grafts possess inherent structural cohesiveness, allowing them to better maintain volumetric stability even in the absence of rigid fixation [13]. Their collagen component enhances adaptability to the defect morphology and facilitates early clot stabilization, which may reduce the mechanical demands placed on the fixation method itself. Previous studies have reported that such composite materials may withstand functional and soft-tissue pressures more predictably than particulate grafts [9,10], suggesting that when using this type of biomaterial, the difference between fixation techniques may be less pronounced.

From a clinical perspective, these findings have several important implications. First, hardware-free stabilization simplifies the surgical procedure, avoids potential complications associated with tack placement, and eliminates the need for retrieval at re-entry. These advantages may be particularly relevant in settings where patient factors, anatomical constraints or surgical expertise limit the feasibility of using fixation devices. Second, the ability to achieve comparable outcomes with sutures alone may lower the cost of care and improve accessibility to regenerative procedures in resource-limited environments.

An additional observation was that buccal bone thickness at 1 mm below the implant platform tended to be lower than at deeper levels. This pattern is consistent with previous reports describing remodeling in the crestal region following augmentation. This phenomenon is commonly attributed to early remodeling dynamics and to the mechanical influence from the peri-implant soft tissues. Because this crestal zone is critical for long-term stability, insufficient buccal bone thickness in this area may increase susceptibility to surface remodeling potentially resulting in mucosal recessions [14] and biological complications such as bleeding on probing [15].

To address these possible complications, alternative augmentation strategies have been proposed, including the so-called L-shape grafting approach [11]. In this technique a composite block is intentionally shaped to extend coronally over the implant platform, thereby reinforcing the most vulnerable portion of the buccal aspect [11,13,16]. This design aims to compensate for anticipated crestal remodeling and to provide a more protective envelope for the peri-implant soft tissues. Given that the present findings showed similar regenerative outcomes between periosteal sutures and titanium tacks, future studies should explore whether the L-shape technique could be combined suture-based stabilization, while preserving the advantages of a hardware-free approach.

The present study has limitations. The sample size was modest and while sufficient to detect large differences between groups, it may not have captured more subtle effects. All procedures were performed by a single experienced operator; nevertheless, an inherent learning curve related to the surgical technique may exist and should be considered when interpreting the results. All the measurements were limited to six months. Although this time-point reflects early functional stability of the regenerated bone, longer-term follow-up is necessary to assess remodeling behavior under functional loading.

5. Conclusions

Periosteal mattress sutures used for graft stabilization during guided bone regeneration with simultaneous implant placement resulted in radiographic buccal bone dimensions at 6 months comparable to those achieved with titanium tacks. Periosteal mattress sutures represent a viable alternative to titanium tacks that may simplify GBR procedures.