A palatal roll envelope technique for peri-implant mucosa reconstruction: a prospective case series study

Abstract

The aim of this study was to evaluate peri-implant soft tissue changes after performing a palatal roll envelope technique. Twelve patients, presenting a labial flat or concave profile before second-stage surgery, underwent soft tissue augmentation using the palatal roll envelope technique with papilla reservation design. The convex profile on the facial aspect, Jemt papilla index, facial mucosal level, marginal bone level, proximal bone levels of the adjacent teeth, and surgical/prosthetic complications were evaluated before surgery as the baseline, and then reevaluated at 1 week, 3 months, and 6 months after surgery. Data were analyzed using the Friedman test and Wilcoxon signed-rank test. Results indicated that the convex profile and the average papilla index score were improved, while the facial mucosal level was adjusted to a level similar to that of the contralateral tooth at 3 months and then remained stable for the follow-up visit. With the limitations identified in this report, the palatal roll envelope technique can be considered an alternative method to augment the soft tissue during second-stage surgery. This technique obviates the need for another surgical site and papillae area, and also reduces the risks of graft shrinkage and scarring on the labial site.

Dental implants have been used successfully to replace missing teeth. With rapid developments in this area, emphasis has shifted from implant osseointegration towards predictable aesthetic success. In order to achieve pleasing aesthetic results, the soft tissue contour around implant-supported restorations should be identical or similar to the contralateral tooth or in harmony with the adjacent natural teeth or artificial restorations. An inadequate vertical dimension of the buccal peri-implant tissue might otherwise lead to an unusually longer crown, and missing volume in the horizontal direction at the buccal aspect could cause a flat or concave profile in the respective region, resulting in food retention and bacterial trap. Therefore, soft tissue management and peri-implant aesthetics have become a focus of implant dentistry.

The pink aesthetic score (PES) is an objective aesthetic criterion comprising five parameters. The five parameters can generally be categorized into two main parts: papilla parts (mesial and distal papillary scores) and facial parts (the curvature of the facial soft tissue, the level of the facial peri-implant mucosa, and the convex profile on the facial aspect). Besides bone augmentation, various flap designs and free connective tissue grafts have commonly been used to enhance the papilla and facial parts. However, it has been reported that papillae adjacent to single-implant restorations regenerate to some extent after 1–3 years of prosthetic placement without any clinical manipulation of the soft tissue, and can be in complete harmony with the adjacent natural teeth. The most likely reason for this phenomenon is that a papilla’s presentation after an implant-supported restoration is mainly determined by the distance between the crestal bone and the base of the contact area. In the case of a single implant, this means that peri-implant papilla levels are dictated by the proximal bone levels of the adjacent teeth. Hence, soft tissue management in the papilla area, or some other method, could restore the papilla faster, but the final volume is similar after a period of prosthetic restoration. On the other hand, a limited flap design, without involving papillae, does protect crestal bone levels compared to a widely mobilized flap design that includes papillae. A large flap could result in a decrease in interproximal crestal bone height. As a result, a limited flap might protect the papilla more effectively than a raised papilla with a soft tissue graft underneath.

Connective tissue grafts have often required a second surgical site, such as the palatal vault or maxillary tuberosity. This can aggravate the discomfort for patients. In one study, more than half of patients preferred the aesthetic result but would not undergo the same soft tissue augmentation procedure again. Moreover, compared to pedicle grafts free connective tissue grafts have a higher risk of shrinkage.

The purpose of this study was to evaluate the efficacy of a palatal roll envelope technique. The technique was performed at implant exposure, and the intention was to reconstruct the convex configuration, facial mucosal level, and peri-implant papillae around maxillary implant-supported restorations with no need for a second surgical site. This technique could also reduce the risks of graft shrinkage and scarring on the labial site. It is a minimally invasive surgery that could be used alone or as a backup for the unpredictable shrinkage of former augmentation procedures.

Materials and methods

Patients included in the study had to reveal the absence of a convex profile before the second surgery ( Fig. 1 a and b ) and no tobacco abuse (maximum 15 cigarettes/day). Twelve patients (seven women and five men), who underwent surgery between December 2009 and July 2010, were included in this study; their age ranged from 19 to 45 years (mean age 30 ± 8.7 years). Each patient had one implant placed at the position of maxillary central incisor or lateral incisor. Ten Osstem GS II implants (OSSTEM Co., Ltd., Busan, Korea) and two Ankylos implants (FRIADENT GmbH, Mannheim, Germany) were used. Implants were allowed to heal for 3 months. The palatal roll envelope technique was performed at second-stage surgery. Immediately after removing the suture, implant-supported interim restorations were fabricated and secured to the dental implants. Peri-implant soft tissue underwent remodelling and matured around these interim restorations for 3 months, and then soft tissue stability was investigated for another 3 months as a follow-up before final restoration.

Fig. 1
(a) Frontal view of the labial concave profile on the maxillary right lateral incisor. (b) Occlusal view of the concave feature on the labial site of the maxillary right lateral incisor. The dotted green line indicates the concave feature. The incision design: the green line indicates the superficial mucosal incision while the yellow line indicates the deeper connective tissue incision. (c) Frontal view of the surgical site immediately after the palatal roll envelope technique. The convex profile was reconstructed while the marginal mucosa was in the coronal position compared to the contralateral tooth. (d) Occlusal view immediately after palatal roll envelope technique. The convex profile is obvious, while the palatal superficial flap is secured back to the original position.

Surgical procedure

A local anaesthetic was administered before treatment. An initial partial-thickness crestal incision was made 1–2 mm towards the palatal site, and 1–2 mm from the teeth adjacent to the edentulous space. Papillae remained adhered to the proximal teeth and were not included in the partial-thickness flap. Both extremities of the incision extended palatally to a point approximately 5–10 mm from the crestal incision. A partial-thickness (superficial half) flap was raised, using a scalpel. Then, within the margin of the superficial flap, the incision of the deeper half was extended down to the bone with a pedicle at the alveolar ridge ( Fig. 1 b). The deeper half was raised with a thin periosteal elevator and formed a subepithelial pediculated connective tissue flap. Both vertical incisions were allowed to extend a little bit towards the labial but within the junction line between the alveolar ridge and buccal plate. These extensions facilitated rolling of pedicle palatal connective tissue. The facial mucosa was undermined and the deeper palatal connective tissue could be rolled and positioned in the labial envelope. The implant cover screw was then retrieved and a healing abutment was inserted ( Fig. 1 c and d). Interrupted sutures (6–0) fixed the palatal superficial flap to the proximal tissue.

Surgical procedure

A local anaesthetic was administered before treatment. An initial partial-thickness crestal incision was made 1–2 mm towards the palatal site, and 1–2 mm from the teeth adjacent to the edentulous space. Papillae remained adhered to the proximal teeth and were not included in the partial-thickness flap. Both extremities of the incision extended palatally to a point approximately 5–10 mm from the crestal incision. A partial-thickness (superficial half) flap was raised, using a scalpel. Then, within the margin of the superficial flap, the incision of the deeper half was extended down to the bone with a pedicle at the alveolar ridge ( Fig. 1 b). The deeper half was raised with a thin periosteal elevator and formed a subepithelial pediculated connective tissue flap. Both vertical incisions were allowed to extend a little bit towards the labial but within the junction line between the alveolar ridge and buccal plate. These extensions facilitated rolling of pedicle palatal connective tissue. The facial mucosa was undermined and the deeper palatal connective tissue could be rolled and positioned in the labial envelope. The implant cover screw was then retrieved and a healing abutment was inserted ( Fig. 1 c and d). Interrupted sutures (6–0) fixed the palatal superficial flap to the proximal tissue.

Prosthetic restoration

Restorative procedures were initiated immediately after removing the suture. A provisional screw-retained abutment lined with composite resin was used as an interim crown. The interim crown was shaped according to the contralateral tooth and manually screwed in. The occlusion was adjusted until there were no contacts in centric occlusion and in protrusive/lateral movements. Patients were instructed on how to properly brush their teeth. The interim crown was adjusted 1–3 times to mimic the natural emergence profile of the contralateral tooth. After 3 months with the interim crown in place, a mature status of the peri-implant mucosa was achieved for each patient ( Fig. 2 a). The interim crown was kept in place for another 3 months. The final restoration was manufactured and seated 6 months after surgery ( Fig. 2 b and c).

Fig. 2
(a) Three months after surgery, the peri-implant soft tissue has remodelled and matured around the interim crown. (b) Frontal view: final restoration. (c) Occlusal view: final restoration. (d) Peri-apical radiograph immediately after interim crown placement (T1). The black arrows indicate the marginal bone level, while the white arrows indicate the proximal bone level. (e) Peri-apical radiograph after final restoration (T3). The black arrows indicate the marginal bone level, while the white arrows indicate the proximal bone level.

Clinical evaluation

Clinical examinations were performed at the following time-points: pre-surgery (T0) and at 1 week (T1), 3 months (T2), and 6 months (T3) after surgery. Data were evaluated at the designated time-points: the convex profile on the facial aspect (CPF; at T0, T1, T2, and T3), facial mucosal level (FML; at T1, T2, and T3), Jemt papilla index score (PIS ; at T1, T2, and T3), marginal bone level (MBL) and proximal bone levels of the adjacent teeth (PBL) (changes between T0 (or T1) and T3), and related surgical and prosthetic complications.

CPF change

CPF was evaluated at T0, T1, T2, and T3 (3 = the over-contour of a CPF, 2 = the presence of a CPF, 1 = the partial presence of a CPF, and 0 = the absence of a CPF).

PIS change

The Jemt papilla index score (PIS ; 4 = hyperplastic papilla, 3 = papilla fills up the entire interproximal space, 2 = papilla fills more than half of the height of the interproximal space, 1 = papilla fills less than half of the height of the interproximal space, 0 = no papilla) was evaluated at T1, T2, and T3.

FML change

The location of the FML in relation to the location of the contralateral tooth or restoration was recorded at T1, T2, and T3. A positive value was given when the FML was in a coronal position when compared to the contralateral tooth or restoration.

MBL and PBL changes

The MBL and PBL were measured using sequential peri-apical radiographs ( Fig. 2 d and e). A peri-apical radiograph was taken with paralleling technique. In the case of an angular difference between T0 (or T1) and T3, the measured distance was standardized by implant length. The marginal bone levels on the mesial and distal aspects of the implants at interval T0 (or T1) to T3 were measured and averaged to the nearest 0.1 mm.

Complications

Complications were also recorded, including peri-implant radiolucency, mobility, soft tissue complications, prosthetic complications, and patient discomfort.

Statistical analysis

Descriptive statistics were used to explain the MBL and PBL changes. The Friedman test, using mean ranks, was applied to evaluate CPF, PIS, and FML changes. The level of significance was set at α = 0.05. If there was an overall statistically significant difference among the mean ranks of CPF, PIS, and FML at the different evaluation points, separate Wilcoxon signed-rank tests were run on the different combinations of related times to examine where the differences actually occurred. The statistical analysis was performed using SPSS v. 11.5 program.

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Jan 24, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on A palatal roll envelope technique for peri-implant mucosa reconstruction: a prospective case series study
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