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Bilateral agenesis of the maxillary lateral incisors: implant-prosthetic treatment and the importance of the conditions of peri-implant tissues in the management of a complex aesthetic case.

Introduction
The optimal resolution of a complex implant-prosthetic case, such as that of a bilateral agenesis of the maxillary lateral incisors, has to be carefully planned both during the surgical stage and management of the provisional replacement in order to achieve the best conditions of soft tissues before definitive prosthetisation..

Presentation of the case study

A.C. female patient with bilateral agenesis of the maxillary lateral incisors comes to our surgery for the first time at the age of sixteen, having previously undergone both functional and fixed orthodontic treatment for a period of four years from the age of twelve.
Once the orthodontic treatment was concluded a porcelain-fused –to-gold bridge spanning units 1.3 to 2.3 was suggested to the patient to replace the missing teeth.
The patient completely rejected this option and approached us for alternative treatment.

Having examined the case from a clinical, radiological and photographic point of view (fig. 1), we chose implant-prosthetic treatment with the use of 2 Straumann Narrow Neck implants to be completed with abutments in zirconium oxide and metal-free porcelain crowns,  to replace the missing members.

In order to effect this treatment the patient must be 19 or 20 years of age thus ensuring total maturation of skeletal growth. It is therefore necessary to use a series of long term provisional replacements for the three years from our first encounter to when the patient is ready for surgery. In addition, further temporary restoration will prove necessary for the management of the post surgical phase as well as a second type of temporary replacement which will help us to condition the soft tissues before placement of the definitive implants.

Management of the pre-surgical phase

The first series of provisional replacements used before skeletal maturation comprises two Maryland bridges in composite resin reinforced with glass fibre. The two units are fixed to adjacent teeth by means of a classic adhesive technique, using a bonding system of three resin based layers and a fluid composite resin which improves contact between the wings and the palatine surfaces of the central incisors and canines (fig.2).
The temporary replacements are applied at the age of sixteen and our patient reaches the age of twenty without them ever becoming detached.
At this stage however it is necessary to change the type of temporary restoration because a bonded temporary replacement cannot be easily removed to allow for surgery nor will it allow us to manage the post-surgical phase and the subsequent manoeuvres necessary to condition the soft tissues as best possible.

Simulated orthodontic treatment is decided on. Aesthetic porcelain brackets are opted for, the brackets are connected to each other via a metal wire with square sections to which two aesthetic units in composite resin are attached in correspondence with the members to be replaced .

This type of replacement is very simple to apply and remove because it is attached with simple elastics (fig.7). Following the surgical stage it will allow us quick and easy access to the site in question whenever we wish.

The Surgical Stage

A local anaesthetic was administered (Ubistesin 1/100,000), two small trapezoidal flaps are opened (fig.8) avoiding the interdental papilla between the central incisors. The two defects are thus revealed, mesiodistally measuring 5 mm. on the right and 5.2 mm. on the left; as imagined and evident from the TC scan, the opening of the flap shows a slight horizontal deficit of the residual bone.

The initial perforation of the cortical bone is effected with a diamond flame insert mounted on a piezoelectric surgical handpiece (Piezosurgery Mectron); the choice of this vibrating insert that doesn’t follow the guidelines laid down by Straumann (fig.12) allows for a more precise initial incision of the cortical bone, thus avoiding dangerous movements which are possible when a handpiece with a rotating bur is used. Subsequently a Straumann calibrated pilot drill with a diameter of 2.2mm. to a depth of 12mm.; this will allow us to insert two 10mm. implants which will be lodged at 12mm. for aesthetic purposes (fig.13)8. A Straumann calibrated bone condenser with a 2.8mm. diameter is then used to a depth of 12mm. (fig.14); the use of this instrument improves bone condensation in the area to be prepared, compaction that guarantees initial stability superior to that achieved when using a drill of the same diameter. The last drill to be used is a Straumann calibrated drill that allows the slight flare necessary for the insertion of the smooth part of the implant itself into the bone (fig.15): the sinking of the smooth neck is necessary in extremely aesthetic cases in order to guarantee better management of the peri-implant soft tissues.
The two Narrow Neck implants are then inserted with a adapter mounted on a surgery counter-angle at a very low number of revolutions (20-25 revs./min.), with continuous irrigation two 2.5mm healing screws are applied to allow appropriate conditioning of the soft tissues during the healing phase (fig.18).
Finally, two small grafts of connective tissue are drawn in correspondence with the palatine area of the two flaps that, contextually, are placed on the vestibular side to reduce the horizontal defects caused by the absence of the roots of the agenesic teeth (fig.19). The simple circular stitches of the suture are in GoreTex 7/0 (fig. 21).

After the operation, the bridge is replaced and once the patient is informed of the pharmacological treatment  and on the correct use of the clorexidine based mouthwash  she is discharged.

Management of the Post-Surgical Stage: provisional replacements and definitive restorations.

Six weeks after placement of the implants the stage regarding conditioning of the soft tissues begins; the healing screws are removed and two peek abutments are inserted in their place which, duly shortened will allow us to modify the appearance of the mucosa to guarantee significantly better aesthetics thereafter.
Two weeks later the appearance and tone of the soft tissues are decidedly good (fig.29); it is therefore possible to make a precise impression (fig.31) for the first provisional replacements to be screwed directly onto the implants.

The patient is then examined every two weeks to see if the soft tissues are modifing. At each check-up, if necessary, the shape of the provisional replacements is modified. The check-ups are after fifteen days, after thirty days (fig.49-52)), after forty five days and after sixty days of the conditioning of the mucosa; a radiographic evaluation is then effected (56/Rx, 57/Rx).
Maturation of the tissues proves satisfactory at this point and another impression is taken for the two zirconium oxide abutments (fig.59) and two new temporary replacements in composite resin (fig.60). As opposed to the previous ones these two will not be conditioned in their shape and inclination by the position of the implants. The slight disparallelism created by the line of the implants will be compensated for by the different inclination of the personalized zirconium abutments. The two replacements, now much closer in shape and size to the definitive units, are fixed with a temporary cement that doesn’t contain eugenol (fig.65-67).

The patient is then examined every two weeks to see if the soft tissues are modifing. At each check-up, if necessary, the shape of the provisional replacements is modified. The check-ups are after fifteen days, after thirty days (fig.49-52)), after forty five days and after sixty days of the conditioning of the mucosa; a radiographic evaluation is then effected (56/Rx, 57/Rx).
Fifteen days later, satisified that the best possible result has been achieved, the final impression is taken; first the porecelain structures is tested and once an impression for position has been taken the two definitive units are created and consequently fixed with a resin based permanent dual cement.

Check-up after 6 months (fig.73-75), after 1 year (fig.78-80).

Conclusions

The optimal resolution of a complex implant-prosthetic case such as the one illustrated must most certainly combine correct surgical procedures regarding implant positioning14 and scrupulous attention to the manipulation of the peri-implant soft tissues15,16,17.
Management of the temporary replacements in conditioning of the mucosa is of fundamental importance if a satisfactory aesthetic result is to be achieved, so much so that the creation of the definitive dental units in the presence of well shaped high quality soft tissues is made easy18.
This condition can only be achieved by continuously monitoring the changes of the “pink” aesthetics that take place as the weeks go by, changes to be encouraged through appropriate intervention, to modify the shape, size and if need be the type of temporary replacement required.

BIBLIOGRAPHY
1 Pract Periodontics Aesthet Dent 1997 Nov-Dec;9(9):1089-94
The double guide concept
Touati B.

2 Compend Contin Educ Dent. 2007 Nov;28(11):604-8;

Fixed and removable provisional options for patients undergoing implant treatment.
Cho SC, Shetty S, Froum S, Elian N, Tarnow D.
3 Clin Oral Implants Res 2006 Dec 17(6): 730-5
Retrospective evaluation of mandibular incisor replacement with narrow neck implants.
Cordaro L, Torsello F, Mirisola Di Torresanto V, Rossini C.

4 Int J Oral Maxillofac Implants. 2004;19 Suppl:73-4

Consensus statements and recommended clinical procedures regarding esthetics in implant dentistry.
Belser U, Buser D, Higginbottom F.

5J Prosthet Dent. 2008 Jan;99(1):2-7.

An esthetic solution for single-implant restorations – type III porcelain veneer bonded to a screw-retained custom abutment: a clinical report.
Magne P, Magne M, Jovanovic SA.

6 Clin Oral Implants Res. 2006 Feb;17(1):94-101.

Prosthetic treatment of maxillary lateral incisor agenesis with osseointegrated implants: a 24-39-month prospective clinical study.
Zarone F, Sorrentino R, Vaccaio F, Russo S.

7 Gen Dent. 2007 Jul-Aug;55(4):320-4.

Conservative rehabilitation of missing teeth before placement of implant dentures: clinical reports.
Akar GC, Berk T, Alev Y, Isiksal E.
8 Clin Oral Implants Res. 2000;11 Suppl 1:59-68.
Basic surgical principles with ITI implants.
Buser D, von Arx T, ten Bruggenkate C, Weingart D.

9J Prosthet Dent. 2007 Oct;98(4):329-32.

Preservation of soft tissue contours with immediate screw-retained provisional implant crown.
Al-Harbi SA, Edgin WA.
10 Pract Periodontics Aesthet Dent. 1996 Nov-Dec;8(9):875-83.
Implant-supported restorations in the anterior region: prosthetic considerations.
Belser UC, Bernard JP, Buser D.

11J Periodontol. 2008 Jun;79(6):1048-55.

Surgical and prosthetic management of interproximal region with single-implant restorations: 1-year prospective study.
Romeo E, Lops D, Rossi A, Stornelli S, Rozza R, Chiapasco M.

12 J Periodontol. 2001 Oct;72(10):1364-71.

Clinical and radiographic evaluation of the papilla level adjacent to single-tooth dental implants. A retrospective study in the maxillary anterior region.
Choquet V, Hermans M, Adriaenssens P, Daelemans P, Tarnow DP, Malevez C.

13 J Periodontol. 1992 Dec;63(12):995-6.

The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla.
Tarnow DP, Magner AW, Fletcher P.

14 Clin Oral Implants Res. 2000;11 Suppl 1:83-100.

Surgical procedures in partially edentulous patients with ITI implants.
Buser D, von Arx T.

15 Int J Oral Maxillofac Implants. 2004;19 Suppl:43-61.

Optimizing esthetics for implant restorations in the anterior maxilla: anatomic and surgical considerations.
Buser D, Martin W, Belser UC.

16 Int J Oral Maxillofac Implants. 2004;19 Suppl:30-42.

Outcome analysis of implant restorations located in the anterior maxilla: a review of the recent literature.
Belser UC, Schmid B, Higginbottom F, Buser D.

17 Int J Periodontics Restorative Dent. 2005 Apr;25(2):113-9.

Influence of the 3-D bone-to-implant relationship on esthetics.
Grunder U, Gratis S, Capelli M.

18 J Oral Maxillofac Surg. 2005 Sep;63(9 Suppl 2):89-96.

Prosthodontic considerations for predictable single-implant esthetics in the anterior maxilla.
Holst S, Blatz Mb, Hegenbarth E, Wichmann M, Eitner S.