Periodontology Literature Review

Ochsenbein, C and Bohannan, HM. The palatal approach to osseous surgery. II. Clinical application. J Periodontol, 34:54,1964.

The palatal approach does not completely substitute buccal osseous reduction. If the clinician has the choice, the palatal approach is more convenient.

The type of the interproximal crater present and the anatomical relationship of the point of bifurcation of the buccal roots of the maxillary molars with the position of the marginal bone will determine the amount of buccal bone that can be safely removed in conjunction with the palatal approach.

Crater classification

(a) class I: 2-3 mm deep with thick buccal and lingual walls; (b) class II: 4-5 mm deep with thinner walls; (c) class III: 6-7 mm deep with a sharp drop of the crater wall from the margin to a broad, flat base; (d) class IV: variable depths with extremely thin buccal and lingual walls sometimes with the base being wider than the orifice. Maxillary first molars have a more coronal buccal furcation and thicker bone covering the buccal surface than the 2nd molar.

Crater therapy:

(a) class I: can be treated by the buccal approach because it is not likely that the buccal furcation will be open. But it should still be treated by removal of the palatal wall and just by that a physiologic contour established, because the slope degree is gradual.
(b) class II: should be treated by the palatal approach because the buccal approach would end up in opening of the buccal furcation. But the palatal bone removal alone will not be sufficient and some bone have to be reduced from the buccal aspect 2-3 mm, creating a favorable slope in the interdental area. It is important to emphasize that the buccal wall should not be eliminated at the beginning. Marginal and interdental bone should be removed gradually and simultaneously.
(c) class III: the palatal approach should also be used for the same reasons in class II. In these cases the clinician has to compromise often times and accept reversed architecture and post surgical depth. Buccal bone should be eliminated similarly to class II. Palatal osseous removal can be carried out as far as the limits of acceptable architecture.
(d) class IV: because the walls are too thin, it is very easy to remove more bone than necessary. The simple exposure of thin bone may end up in resorption; flap should always close these area. The palatal approach should also be the one of choice.

Particular cases:

(a) buccal bone loss involving buccal furca associated with craters: theses case require osteoplasty and ostectomy on the buccal side, but the gross interdental aberrations should be treated from the palatal side.
(b) very coronal buccal furcations: no bone removal on the buccal is possible.
(c) posterior bite collapse may cause root proximity problems in conjunction with buccal furcation problems and no bone can be removed from the buccal aspect.
(d) sometimes tooth extraction is indicated to avoid extensive bone removal in neighbor areas

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