Preservation of the alveolar ridge in the posterior maxillary region 13 January 2015

It is well established that tooth extraction leads to dimensional variations of the alveolar ridge resulting in a significant reduction in osseous volume.

According to a recent systematic review published by Tan et al. in 2012, horizontal bone loss is estimated to be between 29-63 % and vertical bone loss is around 22 %.

In the posterior maxillary region, the decrease in bone volume results in bone resorption mechanisms which occurs following an extraction, but also in an increase in the sinus cavity volume (secondary sinus pneumatization).

Therefore, the use of alveolar preservation techniques can be of great interest in such cases because they sometimes make it possible to put implants in place without using bone augmentation techniques.

The following clinical case is the subject of a retrospective study we carried out which can be read in the magazine Objectif Paro Décembre on the SFPIO's website (http://www.sfparo.org/).

Clinical case

General health and consultation purposes

A 59 year-old female smoker (10 cigarettes per day) who is in good health, is referred by her attending dentist for a consultation on the prognosis of teeth 16 and 17.

December 2012

Clinical and radiographic examination

The clinical examination of this region shows a slight gingival inflammation with the presence of plaque. Teeth 16 and 17 have mesial and distal deep periodontal pockets as well as a Class II mobility (H. R. Mühlemann, 1975).

Fig. 1: Clinical view of teeth 16 and 17 with an indication of the extraction.

At the X-ray examination, we note the presence of several overhanging restorations, several prosthetic restorations in the posterior region, an interradicular lesion on 46 and a replacement of 15 with an implant. On teeth 16 and 17, we observe moderate to severe horizontal bone loss with a damaged interradicular space, the presence of apical lesions and inadequate root canal treatments (Fig. 2).

Fig. 2: Initial dental panoramic X-ray showing the presence of apical lesions, a severe horizontal alveolysis and damaged furcations on teeth 16 and 17.

Treatment choice and plan

The anamnesis and the clinical and radiographic examinations have highlighted an erroneous prognosis on teeth 16 and 17 and, consequently, indication of an extraction.

Thus, a treatment plan was established:

Oral hygiene incentives and education;
Periodontal debridement;
Atraumatic extractions of teeth16 and 17;
Alveoli filling with a graft material.

January 2013
Extraction of teeth 16 and 17

Extraction of teeth 16 and 17 was performed with the least atraumatic possible, flapless and with root separation (Figs. 3a and b).

Figs. 3a and b: Flapless atraumatic extractions Meticulous alveoli curettage and preparation for the placement of a biomaterial.

After meticulous curettage of the alveoli, these were filled with a Bio-Oss® Collagen (Geistlich). The use of biomaterial would limit the mechanisms of bone resorption as well as sinus collapse (Fig. 4).

Fig. 4: Post-extraction alveoli filling with a Bio-Oss® Collagen (Geistlich).

The alveoli filling is guaranteed by the use of a Mucograft® (Geistlich) collagen matrix in order to protect the biomaterial and promote rapid coating of the alveolus by mucosal tissues. Therefore, the matrix is dry cut to the desired size and then placed on the alveoli using the tunnel technique and, finally, fixed with simple 6.0 monofilament sutures (Fig. 5a and b; Fig. 6).

Figs 5a and b: After measuring the size of the alveolus, the matrix is cut to the desired size.

Fig. 6: The alveoli are filled with a Mucograft® (Geistlich) collagen matrix.

Two months after the extractions, good tissue maturation and preservation of the volume of the alveolar ridge are both observed (Fig. 7 and 8).

Fig. 7: Healing at one week: incomplete closure of the alveoli, but the material is protected.

Fig. 8: Healing at two months with good tissue maturation and maintenance of the crestal volume.

September 2013
Implant surgery

At six months, a CBCT was performed to plan the implants on teeth 16 and 17. The radiological examination shows the feasibility of implant placement without a sinus graft (Fig. 9). The following implants are planned:

Tooth 16: Branemark MK4 TiUnite WP 5x10mm implant
Tooth 17: Branemark MK4 TiUnite WP 5x10mm implant

Fig. 9: Dental CBCT showing the preservation of sufficient osseous volume for implant placement on 16 and 17 without the bone augmentation technique.

The implants are not buried using WP 6x5mm healing abutments on both. This non-burying technique avoids a second operation and helps gain time in the gingival healing process (Fig. 10 and 11).

Fig. 10: Slightly conical Branemark (Nobel Biocare) implant placement of large diameter on 16 and 17 without the bone augmentation technique.

Fig. 11: Soft tissue maturation and maintenance of volume around the integrated implants (7 months post-extraction).

February 2014

Control and green light for prostheses placement

The clinical examination shows healthy gingiva and well integrated implants (Fig. 12).

The X-ray control shows a stable peri-implant bone level. (Fig.13).

Fig. 12: Clinical view of the implant prostheses a year after placement. Note the tissue integration of the implant-borne restorations.

Fig.13: X-ray control at 1 year. Note the maintenance of the crestal bone level as well as the maintenance of the inferior part of the sinus at 16.

Fig.14: Sharan's classification (Sharan & Madjar 2008)

Conclusion

Alveolar filling is a pre-implant surgical technique which helps to minimise secondary osseous resorptions in the extractions.

In some cases, the preservation of the alveolar ridge at the posterior maxilla allows for implant placement without the use of a sinus graft.

However, the position of the tooth with respect to the sinus must be considered prior to using this approach. Indeed, Sharan and Madjar (2008) have established a classification of the relationship between the sinus floor and the different topographic positions of the teeth to be extracted (Fig. 14).

According to a preliminary study that we conducted in cases of close sinus proximity with the sinus floor superimposed on the roots (Class IV), this technique did not prevent a sinus graft in about 80% of cases.
However, interesting results can be observed in other situations. This clinical case is a Class 0 according to Sharan's classification.

The technique of preservation of the alveolar ridge by alveolar filling and obturation used in this clinical case has limited the bone remodelling process and preserved a maximum amount of bone and mucosal tissues.

Therefore, implant placement can usually be done without the bone augmentation technique associated with it, resulting in reduced operation time, simplified procedures and a satisfactory final result.

Authors

Hadi Antoun

Private practice limited to Periodontology and Implantology
Paris, Founder of the IFCIA Institute.

Sylvie Pereira

Postgraduate Degree in clinical periodontics, Paris V
Clinical Master's in Periodontics, Paris VII
Exclusive periodontics, Paris