OAI ORAL & Implantology CIC Edizioni Internazionali 2016 July-September; 9(3): 143–150. ISSN: 2035-2468
Published online 2016 November 13. doi: 10.11138/orl/2016.9.3.143.

Increasing volume of vestibular soft tissues in flapless implant surgery through a modified connective punch technique: a controlled clinical trial

M. ANDREASI BASSI,1 C. ANDRISANI,2 S. LICO,3 F. SILVESTRE,4 M. GARGARI,5 and C. ARCURI6

1Private practice, Rome, Italy
2Private practice, Matera, Italy
3Private practice, Olevano Romano, (Rome), Italy
4Departimento de Estomatologia, University of Valencia, Valencia, Spain
5Department of Clinical Sciences and Translational Medicine, University of “Tor Vergata”, Rome, Italy. Department of dentistry “Fra G.B. Orsenigo – Ospedale San Pietro F.B.F.”, Rome, Italy
6Department of Clinical Sciences and Translational Medicine, University of “Tor Vergata”, Rome, Italy

Correspondence to: Prof. Claudio Arcuri, Department of Clinical Sciences and Translational Medicine, University of “Tor Vergata”, Rome, Italy, Tel: +39 06 68371, E-mail: arcuri@med.uniroma2.it

SUMMARY

Purpose
The aim of this article is to make a comparative assessment between the modification of the soft-tissue profile, around the healing cap screws (HCSs), following both the traditional flapless surgery (TFS) and a new modified flapless surgery, named Modified Connective Tissue Punch (MCTP) technique.

Materials and methods
8 patients (3M and 5F) (mean age 54.25±11.247 years) were enrolled in this study. Sixteen two-piece implants were placed on upper jaws, 2 for each patient, 8 with TFS and 8 with MCTP technique. In each patient the implants were placed in edentulous areas, of 2 or 3 adjacent teeth long. MCTP technique was performed on the front implant site (FIS) while the TFS was performed on the rear implant site (RIS). All implants were inserted and covered with healing cap screws (HCSs). Alginate impressions were carried out at the moment of the surgery, at 1 month and 4 months post-operative. Plaster models were poured and subsequently digitally scanned, in order to measure the distance between the gingival outline and the free margin of the HCS. The recorded values were analyzed with the ANOVA test.

Results
The use of MTCP technique, in comparison to TFS, showed a significative better outcome, in terms of vertical increments, of gingiva, on the VS toward the HCSs, during the entire observation period (p = 0.000 for all).

Conclusion
The Authors recommend the use of MCTP technique for a better vestibular soft tissue outcome in flapless implant surgery.

Keywords: flapless surgery, soft-tissue profile, gingival thickness, gingival keratinized tissue, creeping attachment

Introduction

Over the past decade in medicine it has been established the concept of minimally invasive surgery, consisting in taking advantage of advancements experienced in diagnostic techniques and specific surgical instruments, to perform surgical procedures infringing as less damage as possible to the patient (1).

The final goal of implant supported dental rehabilitation is achieving a soft and hard tissue integrity with optimal aesthetics through a minimally invasive surgery combined with an accurate soft-tissue treatment in order to facilitate peri-implant soft-tissue stability over time (2).

Flapless surgical approach was already introduced, in the 1977, by Ledermann. In this procedure, a motor-driven circular tissue punch or a circumferential incision utilizing a surgical blade was used to remove the soft tissue at the implant site without any surgical flap elevation (3). Another approach of flapless implant surgery is penetrating with a round bur directly through the mucosa into the alveolar bone (4).

Among the advantages of this surgery, there is the preservation of the circulation, soft tissue architecture and hard tissue volume at the site, accelerated recovery thus resulting in a better maintenance of the soft tissue profiles, including the gingival margins of adjacent teeth and the interdental papilla (47).

However this surgery inevitably entails the removal of the tissue punch at the implant site, often resulting in a significant reduction in width of the keratinized tissue (KT) around the implant.

The importance of a thick and wide keratinized peri-implant mucosa has been indicated for prevention of mucosal recession and maintenance of peri-implant health. Various techniques to augment keratinized tissue on implant sites have been described in the literature: roll flap; connective graft; epithelial and connective graft; coronally advanced flap (8).

The aim of this article is to make a comparative assessment between the modification of the soft-tissue profile, around the healing cap screws (HCSs), following both the traditional flapless surgery (TFS) and a new modified flapless surgery, named Modified Connective Tissue Punch (MCTP) technique (9).

Materials and methods

8 patients (3 men and 5 women) aged between 35 and 71 years (mean value 54.25±11.247 years) were enrolled in this case series. All patients were in good health condition and gave their informed consent.

Inclusion criteria were:

  • two or three adjacent edentulous sites on the latero-posterior region of the upper jaw;
  • adequate amount of bone volume at implant sites, allowing to perform the traditional flapless implant surgery procedure;
  • good general periodontal health and maintenance;
  • no smoking habitude;
  • absence of positive probing depth, bleeding on probing or plaque on teeth next to the implant sites, at the time of surgery;
  • at implant sites, the KT width (KTW), on the vestibular side (VS), should be at least the same than the selected implant diameter.

Radiographic exams (intra oral X-ray and panoramic X-ray) were initially performed to evaluate the height of available bone. Then the Cone Beam Computed Tomography (NewTom 5G®, QR, Verona, Italy) was then carried out on the selected patients, in order to assess the presence of adequate bone volume at the implant site, for flapless surgery.

The preliminary evaluations of the KTW were measured on the VS at the implant site, by means a periodontal probe, from the center of the ridge toward the vestibule. On the palatal side the presence of palatine fibromucosa made the KTW measurement not needed.

An alginate impression (Alginoplast, Heraeus Kulzer, Hanau, Germany) of the dental arch subjected to surgery was taken, with standard perforated trays, and subsequently the plaster model was poured using a type IV hard plaster (Zeus Stone, Zeus, Roccastrada, GR, Italy). In order to allow the highest precision both the alginate and the plaster were prepared according to manufacturer instructions.

All surgeries have been subject to the same procedural process. The surgery was performed under local anaesthesia (articaine 4% and adrenaline 1:100.000).

In both the TFS and MCTP technique, the only incision is made with a motor-driven circular tissue punch (FAL-31-006-010, FMD, Rome, Italy) of the same diameter of the prosthetic platform of the selected implants (i.e. 4mm). This first incision marked the profile of the connective punch (CP)(Figure 1b). For aesthetic requirements, in each clinical case, the MCTP technique was performed on the front implant site (FIS) while the TFS was performed on the rear implant site (RIS). In the FISs the CPs were first de-epithelialized by means of a sharp Lucas bone curette (spoon 2.4 mm wide) and then on both front and rear implant sites the CPs were detached with the same instrument. The full thickness punches were elevated, keeping them stable with a small tissue tweezers in order to facilitate the graft dissection. While on the RISs not further procedures were executed, involving the soft tissues, in the FISs the same Lucas bone curette was instead used as a periosteal elevator to execute a full-split dissection, in order to create a deep pouch beyond the mucogingival junction on the VS (Figure 1d). This procedure ensured the creation of a recipient site, for the CP, on each FIS. Then, using a small angled dental tweezers the CP, harvested from the FIS, was inserted in the deep portion of the pouch and left in this position during all the procedures of both implant tunnel preparation and implant placement (Figure 1e–f). The CP was completely submerged into the pouch, during the following implant surgery procedure, in order to avoid any undesired movement from its site.

Figure 1Figure 1
A clinical case describing the procedure: a) clinical situation immediately before surgery; b) punch incisions by means of a motor-driven circular tissue punch of the same diameter of the selected implants; c) the punch, on the front implant site (FIS), (more ...)

Then the normal flapless surgical protocol was performed, two-piece implants were inserted [Stone, IDI Evolution, Concorezzo (MB), Italy], in both front and rear implant sites and covered with 4 mm high HCSs [Cone shaped -720403, IDI Evolution, Concorezzo (MB), Italy] (Figure 1h).

The punch was then, in each FIS, pushed along the pouch, from its deeper portion up to its more coronal one, delimited by the transgingival HCS, and stabilized in its position by means of a 2 minutes finger pressure, to relocate the CP in the position where it’s more needed (Figure 1i). This is essential in case there are specific areas where we aim to improve the soft-tissue profile.

Amoxicillin combined with clavulanic acid was administered, with a dose of 2 g preoperatively, followed by 1 g twice a day for 7 days. Ibuprofen 600mg was prescribed to be taken as needed. A soft diet was recommended for 2 weeks, together with appropriate oral hygiene. In each patient, in order to evaluate the healing of soft tissues around HCSs, further plaster models were created, from alginate impressions, taken immediately after the surgery (time 0), at 1 month and 4 months post-operative. The materials and the procedures used were the same of those described before.

The implants were finalized with cemented metal-ceramic bridges after 5 months from the surgery.

All the plaster models were then scanned, and acquired as STL files, with an optical 3D scanner (Easy, Open Technologies, Rezzato, BS, Italy) (Figure 2a, b, c). On each STL file the HCSs of both FIS and RIS were virtually sectioned, along their major diameter (4,75 mm) in a vestibular-palatal direction, by means a specific software (Netfabb Basic 6.4.0 252, Autodesk, Inc., San Rafael, USA) (Figure 2d). At this stage, the sections obtained were evaluated by means of an image analysis software (Image-Pro Plus 4.1, Media Cybernetics Inc., U.S.) and, in particular, the distance between the gingival outline and the free margin of the HCS was measured (Figure 2e, f). Then the differences (Δs), between these measurements at time 0 and both at 1 month and 4 months postoperative, were calculated.

Figure 2Figure 2
a-b-c) Three-dimensional scans of plaster models, respectively, in the immediate post-operative, 1 month and 4 months post-surgery; d) HCSs of both FIS and RIS were virtually sectioned, along their major diameter in a vestibulo-palatal direction; e–f) (more ...)

VS and palatal side (PS) values, both on FISs and RISs, were statistically compared, within the groups, by means of analysis of variance (ANOVA), carried out with a confidence level of 95% (α = 0.05) (Primer Biostatistics Ver. 4.02i; McGraw-Hill Comp., US).

In case of flapless implant surgery local anesthesia can be performed to sampling patients but it may have relevant side effect (1013) and severe complications (14).

This topic can be also potentially investigated with immunofluorescence techniques which are well known since the nineties (15, 16).

Results

Sixteen two-piece implants were placed. Fixtures replaced: 5 molars and 11 premolars. Ten Ø3,75 mm and 6 Ø4 mm implants were placed. Both the implant types had the same prosthetic platform (i.e. Ø 4mm).

The postoperative course was uneventful for all the patients in this study.

At vestibular/palatal sides of the HCSs, no dehiscence of the mucosa was observed.

On VS and PS of the HCSs, both on FISs and RISs, variations of the height of the gingiva were observed.

The average heights and correlated standard deviations were calculated as showed in Tables 1 and 2. The average Δ height and correlated standard deviations, at 1 month and 4 months postoperative, were calculated as showed in Tables 3 and 4.

Table 1Table 1
Front implant sites, average height variations on both vestibular and palatal sides.
Table 2Table 2
Rear implant sites, average height variations on both vestibular and palatal sides.
Table 3Table 3
Front implant sites, average Δ height on both vestibular and palatal sides.
Table 4Table 4
Rear implant sites, average Δ height on both vestibular and palatal sides.

Significant differences were found concerning:

  • On the VS: RISs at time 0 vs 1 month (p = 0.003) and at time 0 vs 4 months (p = 0.002); FISs vs RIS, at time 0 (p = 0.037).
  • On the PS: RISs at time 0 vs 4 months (p = 0,014); FISs at time 0 vs 4 months (p = 0.012).

Highly significant differences were found concerning:

  • VS vs PS: both on RISs and on FISs, at 4 months (p = 0.000);
  • Within the groups of FISs (time 0, 1 month, 4 months) on VS (p = 0.000 for all);
  • FISs vs RISs on VS, at 4 months (p = 0.000).

Not significant differences were found concerning:

  • RISs at time 0 vs 1 month (p = 0.128) and at 1 month vs 4 months (p = 0.300);
  • On Vestibular Side: RISs at 1 month vs 4 months (p = 0.939);
  • VS vs PS: on FISs at time 0 (p = 0.133); on RISs at time 0 (p = 0.302);
  • On Palatal Side: FISs vs RISs at time 0 (p = 0.371), at 1 month (p = 0.188) and at 4 months (p = 0.558); RISs at time 0 vs 1 month (p = 0.128) and at 1 month vs 4 months (p = 0.300); FISs at time 0 vs 1 month (p = 0.300) and at 1 month vs 4 months (p = 0.120).

Discussion

Healthy soft tissue surrounding dental implants is essential for health, function, and aesthetics (4). The presence of attached gingiva around implants is important to prevent recession of marginal tissue, to provide tight collar around implants, to prevent spread of peri-implant inflammation and also to enable patients to maintain good oral hygiene (4, 8, 17).

The MCTP technique, recently proposed, is simple, easy to perform and allows to satisfy all the above requirements (9). As confirmed by previous clinical results, the augmentation of gingival thickness is always present and seems to be stable at 1 year follow-up (9). Regarding the changes of KTW, they appear to be minimal but always favourable. In the Authors experience, the critic factor that leads towards KT augmentation it’s the depth of the recipient site where the graft is placed: when the connective punch results to be enough superficial, it seems to be able to induce a transformation of the external connective tissue into KT, thus augmenting the peri-implant KT (9). In the present study the use of MTCP technique, in comparison to TFS, shows a significative better outcome, in terms of gingival vertical increment, on the VS toward the HCSs, during the entire observation period (i.e. time 0, 1 month, 4 months) (p = 0.000 for all). This phenomenon can be easily explained as, in the FISs, a CP is placed as graft, into the vestibular pouch. The CP increases the thickness of soft tissues, immediately after the surgery and also at 1 month and 4 months post-operative, due to its maturation. This “creeping attachment” has been mainly reported surrounding teeth (1822), and few papers only reported it surrounding implants (23, 24). This phenomenon already described in TFS (25) seems to be more evident when the MTCP technique is used.

On the other hand both MTCP technique and TFS show a worse outcome on the PS probably due to the three-dimensional placement of the implant that is usually placed more palatally than vestibularly in order to prevent vestibular gingival recession (26). Not significative differences were found on PS between FISs and RISs at time 0 (p = 0.371), at 1 month (p = 0.188) and 4 months (p = 0.558). This outcome is mainly due to the fact that MTCP technique involves the VS only.

On RISs the VS showed a better outcome than PS at 4 months follow up (p = 0.000) more likely due to the three-dimensional placement (26).

The results obtained with this technique confirmed that the use of CP at implant placement is effective in increasing soft tissue thickness and improving aesthetics, as declared with other techniques in literature (17).

The success of both dental implant and prosthetic treatment is dependent on the establishment of a stable soft-tissue barrier that is able to shelter the underlying osseous structures and to guarantee a peri-implant gingival aesthetics over time.

Different approaches have been used to augment keratinized tissue on implant sites (e.g. Roll flap, connective graft, epithelial and connective graft, coronally advanced flap) (8).

Although it has been shown that it is possible to improve the soft tissue profile with all these techniques, we found this procedure the most simple to execute when flapless implant surgery is performed.

Other techniques often require longer surgical-time and dedicated instruments, present more difficulties in the surgical steps and have a higher morbidity rate (8, 24).

The Authors recommend the use of the MCTP technique to reduce the number of aesthetic complications and soft tissue defects in flapless implant surgery. Further studies are needed to evaluate the extent of soft tissue thickness increment on the vestibular side achievable with this technique both on upper and lower sites of the dental arches.

References
1.
Romero-Ruiz MM, Mosquera-Perez R, Gutierrez-Perez JL, Torres-Lagares D. Flapless implant surgery: A review of the literature and 3 case reports. J Clin Exp Dent. 2015;7(1):e146–52.
2.
Kois JC. Predictable single tooth peri-implant esthetics: five diagnostic keys. Compend Contin Educ Dent. 2001;22(3):199–206. quiz 08.
3.
Sclar AG. Guidelines for flapless surgery. J Oral Maxillofac Surg. 2007;65(7 Suppl 1):20–32.
4.
Bayounis AM, Alzoman HA, Jansen JA, Babay N. Healing of peri-implant tissues after flapless and flapped implant installation. J Clin Periodontol. 2011;38(8):754–61.
5.
Azari A, Nikzad S. Flapless implant surgery: review of the literature and report of 2 cases with computer-guided surgical approach. J Oral Maxillofac Surg. 2008;66(5):1015–21.
6.
Becker W, Goldstein M, Becker BE, Sennerby L. Minimally invasive flapless implant surgery: a prospective multicenter study. Clin Implant Dent Relat Res. 2005;7(Suppl 1):S21–7.
7.
Becker W, Goldstein M, Becker BE, Sennerby L, Kois D, Hujoel P. Minimally invasive flapless implant placement: follow-up results from a multicenter study. J Periodontol. 2009;80(2):347–52.
8.
Nemcovsky CE, Artzi Z. Split palatal flap. II. A surgical approach for maxillary implant uncovering in cases with reduced keratinized tissue: technique and clinical results. Int J Periodontics Restorative Dent. 1999;19(4):385–93.
9.
Andreasi Bassi M, Andrisani C, Lopez MA, Gaudio RM, Lombardo L, Lauritano D. Modified connective tissue punch technique to increase the vestibular/buccal keratinized tissue on flapless implant surgery: a case series. J Biol Regul Homeost Agents. 2016;30(2 Suppl 1):29–34.
10.
Feltracco P, Barbieri S, Galligioni H, Pasin L, Gaudio RM, Tommasi A, Zucchetto A, Trevisiol P, Ori C, Avato FM. A fatal case of anaphylactic shock during paragliding. J Forensic Sci. 2012;57(6):1656–8.
11.
Feltracco P, Gaudio RM, Avato FM, Ori C. Authors’ Response (Letter). Journal of Forensic Sciences. 2012;57(5)
12.
Feltracco P, Gaudio RM, Barbieri S, Tiano L, Iacobone M, Viel G, Tonetti T, Galligioni H, Bortolato A, Ori C, Avato FM. The perils of dental vacation: possible anaesthetic and medicolegal consequences. Med Sci Law. 2013;53(1):19–23.
13.
Gaudio RM, Barbieri S, Feltracco P, Tiano L, Galligioni H, Uberti M, Ori C, Avato FM. Traumatic dental injuries during anaesthesia. Part II: medico-legal evaluation and liability. Dent Traumatol. 2011;27(1):40–5.
14.
Gaudio RM, Barbieri S, Feltracco P, Spaziani F, Alberti M, Delantone M, Trevisiol P, Righini F, Talarico A, Sanchioni R, Spagna A, Pietrantonio V, Zilio G, Dalla Valle R, Vettore G, Montisci M, Bortoluzzi A, Sacco A, Ramacciato G, Pasetti A, Mognato E, Ferronato C, Costola A, Ori C, Avato FM. Impact of alcohol consumption on winter sports-related injuries. Med Sci Law. 2010;50(3):122–5.
15.
Petruzzi M, Campus G, Paparusso F, Lucchese A, Lauritano D, De Benedittis M, Serpico R. Analysis of plasma fibronectin levels in patients affected by oral lichen planus. European Journal of Inflammation. 2012;10(1):45–50.
16.
Petruzzi M, Lucchese A, Nardi GM, Lauritano D, Favia G, Serpico R, Grassi FR. Evaluation of autofluorescence and toluidine blue in the differentiation of oral dysplastic and neoplastic lesions from non dysplastic and neoplastic lesions: a cross-sectional study. J Biomed Opt. 2014;19(7):76003.
17.
Zweers J, Thomas RZ, Slot DE, Weisgold AS, Van der Weijden FG. Characteristics of periodontal biotype, its dimensions, associations and prevalence: a systematic review. J Clin Periodontol. 2014;41(10):958–71.
18.
Harris RJ. Creeping attachment associated with the connective tissue with partial-thickness double pedicle graft. J Periodontol. 1997;68(9):890–9.
19.
Matter J, Cimasoni G. Creeping attachment after free gingival grafts. J Periodontol. 1976;47(10):574–9.
20.
Matter J. Creeping attachment of free gingival grafts. A five-year follow-up study. J Periodontol. 1980;51(12):681–5.
21.
Bell LA, Valluzzo TA, Garnick JJ, Pennel BM. The presence of “creeping attachment” in human gingiva. J Periodontol. 1978;49(10):513–7.
22.
Otero-Cagide FJ, Otero-Cagide MF. Unique creeping attachment after autogenous gingival grafting: case report. J Can Dent Assoc. 2003;69(7):432–5.
23.
Pereira Neto AR, Passoni BB, de Souza JM Jr, de Souza JG, Benfatti CA, de Magini RS, Bianchini MA. Creeping attachment involving dental implants: two case reports with a two-year follow-up from an ongoing clinical study. Case Rep Dent. 2014;2014 756908.
24.
Oh TJ, Shotwell JL, Billy EJ, Wang HL. Effect of flapless implant surgery on soft tissue profile: a randomized controlled clinical trial. J Periodontol. 2006;77(5):874–82.
25.
Abraham MT, Chiang SK, Keller GS, Rawnsley JD, Blackwell KE, Elashoff DA. Clinical evaluation of non-ablative radiofrequency facial rejuvenation. J Cosmet Laser Ther. 2004;6(3):136–44.
26.
Handelsman M. Surgical guidelines for dental implant placement. Br Dent J. 2006;201(3):139–52.