A few weeks ago while I was at my office in Barcelona performing an implant surgery with a connective tissue graft, I was thinking about how much I used to enjoy these kind of surgeries and how they stopped being so enjoyable the minute they became routine. I remember that day, I chose “The 80´s playlist” from my iPod. It was what I used to listen to bring some action during my not-so-large-days of work (yes, it’s amazing to hear from some of my pals how proud they are when they perform a full-arch immediate loading or a bilateral sinus lift surgery at 9pm. I congratulate them for that but it doesn’t suit my lifestyle anymore, although I might be poorer for refusing to perform block grafts after midnight).
While “Right between the eyes” was playing in the background (I know, sometimes I feel a little bit nostalgic about the eighties), something not so usual happened: I was just finishing harvesting a huge slice of connective tissue and the palatal artery just decided to be where it shouldn’t be (or maybe that was my first complaint – “anatomical aberration”, I said).
That was what I consider a shot “Right between the eyes”. First of all, I solved that bloody mess constraining the palatal artery with a ligature suture and then pressuring with a gauze for 15 minutes. Fortunately, it stopped bleeding and my patient didn´t even realize that something wrong happened. I finished the surgery without any other inconvenience (almost any inconvenience : my patient just couldn’t pay the bill. Not even some of it. It was almost summer and he really wanted to have more money to spend for his vacations. I don’t blame the chap, I would do the same).
After finishing the surgery, I thought that maybe If I create a few topics with some rules and concepts on a small piece of paper , I would help other colleagues to avoid these kind of complications and maybe help them enjoying plastic periodontal and implant surgery. So I decided to create this article in collaboration with Delia (yes, she´s another great Facebook friend; I love the way she works and her tenacity. She´s very friendly and one of the nicest persons I have ever met on social network).
So “Let´s get serious”:
We all know that performing soft tissue autografts have been a progressively trendy surgery for the past 20 years despite the fact that first articles about autografts in clinical periodontology where published more than 40 years ago (Haggerty 1966; Nabers 1966; Sullivan & Atkins 1968; Edel 1974). Our assumption is that the increasing “democratization” on the use of soft tissue autografts is correlated with the “democratization” of implant therapy as well.
But why we do use soft tissue grafts?
Two main goals are pursued:
- Increase the width of keratinized tissue
- Increase soft tissue volume
After several authors realized that the width of keratinized tissue around teeth was clinically overrated, the use of free gingival grafts (FGG) started to be an option to solve aesthetic defects like soft tissue recessions (Bernimoulin et al. 1975; Miller 1982), soft tissue ridge augmentation (Seibert 1983) and for something that is quite trending nowadays: Socket preservation in the aesthetic zone (Landsberg & Bichacho 1994).
We all know that FGG have two great limitations: volume augmentation and aesthetic result (sometimes the color and surface doesn’t blends in with the receptor site) and soon the advantages of using subepithelial connective tissue graft (SCTG) started to be evident in the literature (B. Langer & Calagna 1980; B. Langer & L. Langer 1985). Considering the advantages of the SCTG over the FGG we are going to focus this article on SCTG.
We also should know the role of inherent factors regarding genetic determination of gingival tissues and for that I recommend you the articles from Karring ((Karring et al. 1971; Karring et al. 1975) and also this lecture from Juan Alberto Fernandez on Oralsurgerytube which I strongly recommend you to subscribe.
The masticatory mucosa of the hard palate is composed of three histologic layers:
- The epithelium (300 µm thick, 0,3 mm this is really quite thin layer)
- Lamina Propia
Fig. 1- Layers that can be observed at the masticatory mucosa.
The thickness of the masticatory mucosa vary substantially from patient to patient and also depending the donor site it can be more thick in the tuberosity (4 mm) than in the palate (3 mm) (Muller et al. 2000). Another important finding by Gapsky is that the subepithelial connective tissue from the tuberosity is very dense, coarse and collagen-rich tissue with less fat and glandular tissue which all these may have some clinical interest (Gapski et al. 2006).
Another anatomical consideration that should always be respected is the great palatine artery (GPA). To keep it simple I`m going to use the reference from Monnet-Corti where the main branches of the GPA were +/- 12 mm distance from the gingival margin at the canine region +/- 14 mm at the second molar region (Monnet-Corti et al. 2006). Although this study has some inaccurate measurements (the gingival margin is not always a good reference) almost all the authors assumed that the GPA can be found at a distance of 76% of the global palatal height measuring from the cementoenamel junction of the first molar.
Fig. 2- The publication from Monnet- Corti stated that the GPA were +/-12 mm distance from the gingival margin at the canine region +/- 14 mm at the second molar region.
Fig. 3- A consensus brought us this helpful measurement where the GPA may be found at 76% of the global palatal height.
Donor site for a connective tissue graft
We should consider two areas of interest:
- Anterior palate: Extensive and large surface
- Posterior palate (tuberosity and lateral palate): Tuberosity is very voluminous which is a good option for a alveolar ridge augmentation and lateral palate is well indicated for recession coverage. They are both too dense and firmer than the anterior palatal so graft from tuberosity and posterior lateral palate are very unlikely to undergo to a postoperative shrinkage but on the other hand they are more prone to undergo necrosis than anterior palate. I strongly advice you to completely cover this grafts.
A good option to decide the donor site is to use an endodontic needle with a silicon disc. With this assessment it can also be felt the transition between the lamina propia and the adipose submucosa (Zucchelli et al. 2010).
The harvesting techniques seek to achieve the more volume of tissue possible, minimize post-operative pain and reduce the risk of complications. Lest look at some of those techniques.
1. SCTG harvesting from the anterior palate
I will only explain here the single incision technique which in my opinion has the best postoperative behavior for the patient whereas a primary closure is achieved when this technique is used.
First an horizontal incision along the row of the teeth from the mesial border of the first molar and the lateral incisor, 2 mm apical to the gingival margin and 1.5 mm deep. The remaining incisions are performed under the mucosal surface.
The flap should not be extended more than 10 mm apical from the cementoenamel junction of the maxillary posterior teeth, so if we count with the 2 mm distance from the first horizontal incision we should know that no more than 8 mm deeper the extent of the graft. Therefore we can use as a reference a No. 15 scalpel blade which cutting portion has approximately 8 mm(Zuhr et al. 2014).
After we decided the size of the graft two vertical and horizontal incisions should be created inside the envelope. This connective tissue harvested can be obtained with or without periosteum but we should assume that those harvested with periosteum will have better mechanical behavior but more negative postoperative consequences.
For the following wound closure horizontal compression sutures is a good option (see video).
Fig. 4, 5, 6 – The first horizontal incision 2 mm below the gingival margin and the 8 mm (the size of the No 15 blade) immediately below those 2 mm are the security or comfort zone where the SCTG can be harvested.
This sequence explains the step by step of a SCTG harvesting from the palate.
2. SCTG harvesting from the posterior lateral palate
In this case is better to use the trap-door technique with one horizontal incision on the first or second molar and two vertical incisions that should be extended 1 mm further than the intended apicocoronal dimension of the graft. This two vertical incision will allow us better access to the apical incision line. Like in the technique described previously, a split-thickness flap is prepared parallel to the external mucosal surface.
After removing the connective graft, single interrupted sutures can be used to achieve primary closure of the wound.
Fig. 7- Same rules explained before but for this technique a trap-door approach results in a better visualization of the donor site.
3. SCTG harvesting from the lateral palate with free gingival graft that is deepithelialized extraorally
In this case 2 vertical and 2 horizontal incisions are performed with 1.5 mm deep. The resultant rectangle should be the size of the desired graft. Then the blade is rotated parallel to the mucosal surface and the soft tissue is detached with both epithelialized and connective tissue fraction that is further split with a new blade. For this technique magnification is important to perform the deepithelialization extraoraly and the donor site is left for healing by second intention (big disadvantage).
Fig. 8- A rectangle or square surface of the masticatory mucosa is delimited with the blade and removed. After the graft is prepared extraoraly where the epithelium is removed.
4. SCTG harvesting from the maxillary tuberosity
This is so far the easiest technique to obtain a good connective tissue graft. Of course if the last present teeth is a first molar, more extension will have the graft, but this also can be performed with the presence of the second and the third molar.
Two perpendicular converging incisions with a “V” shape extended as distal as possible but always inside the masticatory mucosa. The incision should include the tissue around the distal tooth surface. Sometimes I perform this surgery after removing a third molar if then a connective tissue graft is needed for other surgery.
Fig. 9- Converging incision with a “V” shape at the tuberosity is a reliable and easy approach to get a nice amount of connective tissue to graft. For those who are beginning with soft tissue augmentations maybe this should be the chosen approach for the first cases.
It also is an option to get a connective tissue graft to perform immediate implants.
So far autologous connective tissue graft is consider the gold standard although this represents a second surgical wound to our patients and all the complications that may represent (necrosis, pain, swelling, infection). A lot of efforts by scientists and manufacturers aim to create a biomaterial that could avoid harvesting autologous grafts from our patients (although is something that I perform very often I´m eager to have in a small bottle a gold standard without creating an extra surgical wound on my patients). On the other hand, if finally innovation brings us a biomaterial with similar behavior than the autologous graft, there will be no limitation for grafting, something that today can happen and sometimes during a surgery we need some more graft and we have to decide if we perform another surgical wound to our patient to get another great connective tissue graft or just handle the surgery with the graft from the first attempt.
Lately another techniques like socket shield technique may avoid the use of a connective tissue graft when an immediate implant is performed in the aesthetic zone because in this cases, where the buccal bone is preserved due to the presence of a fragment of the hopeless teeth, there is no need to enhance the bucal volume. You can learn more about this technique here.
Harvesting autologous connective tissue graft is a common procedure nowadays and this small article aims to help dentists to perform their first soft tissue graft although I strongly recommend to read the associated literature to have a clear comprehension of this meticulous procedure.