Anatomical Obstacles in Implantology
- UPPER MAXILLARY
- The pterygopalatotuberous region
The surgical risk of the pterygopalatotuberous region is essentially vascular at the level of the greater palatine canal.
The risk is mainly at the level of the descending palatine artery. Injury to the greater palatine artery constitutes a major hemorrhagic risk.
- The molar and premolar region
It is located between the tuberosity of the maxilla and the canine. It is limited above by the floor of the maxillary sinus and below by the alveolar edges.
- The canine region
the general shape of a triangular pyramid with a lower base
In case of severe resorption of the alveolar process, particularly in the case of total or extensive partial edentulousness, the anchoring of the implant will be in the canine pillar and will be dependent on the pneumatization of the maxillary sinus and the nasal cavity.
- The maxillary incisor region
A region that does not present any major anatomical risks in implantology, the placement of implants at this level often poses problems due to centripetal resorption phenomena that can be significant.
The incisive foramen, when large, can constitute an anatomical obstacle that can be filled if necessary for the stability of an implant, after removal of the pedicle that it contains.
Anatomical Obstacles in Implantology
- LOWER MAXILLARY
- The mandibular molar region
A common site in implantology. The shape and relationships of the bone in this region are directly dependent on the extent and degree of bone resorption.
- Mandibular premolar region
The mental foramen is the predominant element of this region, to be taken into consideration in implant surgery.
This area marks an anatomical and implant boundary : in front, the symphyseal region, generally favorable to the placement of fixtures in ideal conditions; behind, the posterior mandibular region whose resorption, associated with the position of the mandibular pedicle, can make surgery more delicate.
- Perforation of the lingual cortex , with a risk of damage to the underlying anatomical structures (mylohyoid vessels and nerves). The consequences would be more irritating and painful than dangerous.
- The mandibular incisor-canine region
- Located in front of the mental foramens
- Significant corticalization
- High density of cancellous bone
- The absence of major anatomical obstacles
- Fracture of the mandible in cases of extreme resorption .
- MICROSCOPIC ANATOMY AND BONE TYPOLOGY
The bone response around an implant is different depending on whether it occurs in cortical or cancellous bone.
- Type I : The jaw is composed almost entirely of homogeneous compact bone;
- Type II : A thick layer of compact bone surrounds a core of dense trabecular bone;
- Type III : a thin layer of cortical bone surrounds a core of dense trabecular bone;
- Type IV : A thin layer of cortical bone surrounds a core of low-density trabecular bone
Anatomical Obstacles in Implantology
- Anatomical variation and implantology
Extraction for implant purposes:
When and how to extract?
Except in cases of painful emergencies, tooth extraction for periodontal reasons is generally decided and performed after reassessment of the etiological therapy. The inflammation is then reduced and healing occurs in good conditions. The extraction aims to preserve the residual bone volume. On multi-rooted teeth, a separation of the roots is always performed in order to obtain an atraumatic procedure.
Maxillary and mandibular resorption and induced anatomical modifications:
a. At the mandibular level
Anterior crestal resorption is four times faster than that of the maxilla. In addition, resorption is faster in the lingual region (centrifugal resorption).
The crest thus progressively loses its height and its mesiodistal width. The vertical resorption of the mandible brings the mandibular canal closer to the crestal edge.
b. At the maxillary level
Resorption in the vertical direction is associated with greater resorption in the vestibular direction (centripetal resorption).
Vertical resorption often limits the available bone volume under the maxillary sinuses. The maxillomandibular relationship is then modified.