Final - Osseous Resection

What *instruments are used for osseous resective surgery*?

- hand instruments - rotary instruments --> see IMAGE for examples

Diagnosing/evaluating osseous defects: *Probing*

- provides *ONLY LINEAR measurements of the soft tissue pocket* --> *"needs to be done under local anesthesia"* - *transgingival probing (bone sounding)* --> *indicates the topography of the bony defect in TWO directions (vertical and horizontal)*

How are *osseous defects diagnosed/evaluated*?

- radiographs - probing "one is NOT sufficient, we need both"

Describe *flattening of the interproximal bone*:

- requires removal of very small amounts of supporting bone - indicated when interproximal bone levels vary horizontally

What are the *DISADVANTAGES of the LINGUAL approach to osseous resection*?

- the *LINGUAL bone is often THICK* - a *considerable amount of osteoplasty is required to achieve proper architecture*

Patient case example:

--> see IMAGE

Patient case example:

--> see IMAGE increased probing depths on the buccal and interproximal aspects of the molar

Patient case example:

--> see IMAGE increased probing depths on the palatal aspect of the molar

--> see IMAGE

--> see IMAGE for a ONE-wall bony defect

--> see IMAGE

--> see IMAGE for a TWO-wall bony defect "It is important to note that the picture illustrates a crater defect. Two of the walls are root surfaces. That is not the same as other two wall defects where you will have a buccal wall and an interproximal wall. That would have a better therapeutic prognosis."

--> see IMAGE

--> see IMAGE for a radiographic example of horizontal bone loss

--> see IMAGE

--> see IMAGE for a radiographic example of vertical bone loss

--> see IMAGE

--> see IMAGE for a visual of HORIZONTAL bone loss

--> see IMAGE

--> see IMAGE for a visual of VERTICAL bone loss

--> see IMAGE

--> see IMAGE for a visual that shows how "VERTICAL bone loss can only have the bony crest on the molar brought in a vertical direction by extruding the tooth"

What are the *ADVANTAGES of the LINGUAL approach to osseous resection*?

--> see IMAGE for the MANDIBULAR *LINGUAL approach* to osseous resection "we are essentially accessing the lingual because we have better access to the embrasure space" - *LESS removal of supporting bone* due to lingual inclination (approximately 20 degrees) in posterior teeth - the *DEEPEST point of most interdental osseous defects is usually positioned LINGUALLY* - *LESS chance to expose the lingual furcation* (positioned more apically)

What are the *ADVANTAGES of the PALATAL approach to osseous resection*?

--> see IMAGE for the MAXILLARY *PALATAL approach* to osseous resection - *AVOIDS removing bone from the facial*, exposing molar furcations - the palatal aspect has *WIDER INTERDENTAL EMBRASURES* for access during surgery and for post-surgical maintenance - a *BETTER ESTHETIC RESULT* is achieved

--> see IMAGE

--> see IMAGE for the final osseous contours we'd like to be left with

--> see IMAGE

--> see IMAGE to see how one reshapes the marginal bone to resemble the alveolar process undamaged by periodontal tissue (*positive architecture vs. negative architecture*)

Does the LINGUAL approach to osseous resection occur in the mandible or maxilla?

MANDIBLE

Does the PALATAL approach to osseous resection occur in the mandible or maxilla?

MAXILLA

Can osseous resection be approached from the lingual OR the palatal direction?

YES

Is it important to *AVOID osseous resection in ESTHETIC AREAS*?

YES, in these areas we may consider open flap debridement instead (instead of resecting/removing bone)

Can a *CBCT be used for the diagnosis/evaluation of osseous defects*?

Yes, but *CBCTs can be controversial* "there are cases where this is not indicated - it is found to be indicated for advanced lesions or in maxillary molars"

Of the different bony defect classifications, which is the *most predictable type of defect for growing bone*? ***IMPORTANT

a *THREE-wall infrabony defect* (because it has better blood supply for retaining the graft material) --> see IMAGE

Which is a more predictable bony defect classification for growing bone, a TWO-wall bony defect or a ONE-wall bony defect?

a *TWO-wall bony defect is more predictable for growing bone* than a ONE-wall bony defect

Technique used for osseous resective surgery:

a *basic flap approach* includes: - local anesthesia - *FULL-thickness, APICALLY-positioned flaps* - thorough soft and hard tissue debridement

What do the different bony defect classifications tell us about what type of osseous surgery we should be using? ***IMPORTANT

as you move from a THREE to ONE-wall infrabony defect, you tend to think of using ADDITIVE osseous surgery LESS and then SUBTRACTIVE osseous surgery MORE "if there is severe bone loss, we start to think about open flap debridement"

Osseous resection is performed at the expense of ______________ _______________ and _________________ _______________.

bony tissue attachment level

What is an *osseous defect*?

concavity or deformity in alveolar bone involving one or more teeth osseous deformity resulting from periodontal disease

What is an *ostectomy*?

includes the *REMOVAL of tooth supporting bone* (HAND instruments) --> see IMAGE to compare osteoplasties vs. ostectomies

What is an *osteoplasty*?

refers to reshaping the bone *WITHOUT removing tooth supporting bone* (ROTARY instruments) --> see IMAGE to compare osteoplasties vs. ostectomies

What is *osseous surgery*?

the general term for procedures which *modify* and *shape* bone defects and deformities may be defined as the procedure by which *changes* in the alveolar bone are accomplished to eliminate deformities induced by the periodontal disease process or other related factors, such as exostoses

What is *FLAT architecture*?

when interdental and radicular bone are at the SAME height (level) --> see IMAGE

What is *NEGATIVE architecture*?

when the INTERDENTAL bone is apical to the RADICULAR bone --> see IMAGE

What is *POSITIVE architecture*?

when the RADICULAR bone is apical to the INTERDENTAL bone --> see IMAGE

What are the different *types of osseous surgery*?

*ADDITIVE osseous surgery (regenerative)* *SUBTRACTIVE osseous surgery (resective)*

What *determinants are used to decide which osseous defect therapy is ideal*?

*DEPTH of the defect* *WIDTH of the defect* (at the coronal extent) *defect TOPOGRAPHY* (i.e. number of remaining bony walls, number and configuration of the adjacent root surfaces) "root surfaces are not vascular. They are avascular surfaces. So doing a bone graft against bony walls, essentially is helpful because we can get blood supply from the bony walls. Bone grafts against tooth surfaces mean that we are not getting any blood supply from that tooth surface. That negatively affects the therapeutic prognosis."

What happens if you try to use periodontal regeneration to treat SHALLOW infrabony pockets (1-2 mm deep) instead of osseous resective surgery?

*if periodontal regeneration is done on SHALLOW infrabony pockets, it will result in net LOSS of bone 1 year after surgery* "The graft will then start to spill out. You need to have a containable bony defect throughout the process to stimulate periodontal regeneration."

Technique used for osseous resective surgery CONT.:

*osseous resective phase* includes: - vertical grooving - radicular blending - flattening interproximal bone - gradualizing marginal bone

Osseous resective surgery is indicated for SHALLOW infrabony pockets (1-2 mm deep). If the *infrabony pocket is >2 mm*, what treatment option is indicated?

*periodontal regeneration* (i.e. regeneration of the bone via a graft)

What is the *basis for performing osseous resective surgery*?

*periodontitis* --> see IMAGE "Periodontal disease tends to attacks the underlying bony structure or architecture. This resorptive process results in sharp, uneven marginal deformities or irregularities (this can be seen in the second, third and fourth image). The gingival tissues are soft and they tend to follow a more fluid form. So these differences tend to result in deep pockets that can be probed."

What is a *major contraindication for SURGICAL osseous defect therapy*?

*poor oral hygiene*

*AFTER bone removal*, what should be done with the flap?

*the flap should be positioned more APICALLY to cover the marginal bone crests with flap-tooth contact 1-2 mm supracrestally and sutured*

*Failure to remove small bony discrepancies at the line angles of the teeth* leads to the development of "_______________ ___________"*.

*widow's peaks* if these are left behind, it allows the tissue to rise to a higher level than the base of the bone loss in the interdental area "Remember gum tissue always conforms to the bone that is underneath it. So if you leave the widow's peak at the line angle, that gingival tissue will rise up. If that gingival tissue rises up, what will your pocket be? Deep. It will be harder to clean. Bacteria will get into the deep pocket. You will find more and more bacteria packing into that deep pocket. From there it could create an angular defect from the bacteria." "once these are removed, it allows the soft tissues to move in an APICAL direction which is desired" --> see IMAGE

What are the *INDICATIONS for osseous resection*?

- *SHALLOW infrabony pockets (1-2 mm deep)* [*REMEMBER: INFRABONY POCKETS ARE NOT SYNONYMOUS WITH PROBING DEPTHS*, infrabony pockets are defined as the alveolar crest to the base of the bony pocket, *YOU CANNOT DO OSSEOUS RESECTIVE SURGERY ON PATIENTS WITH 1-2 MM PROBING DEPTHS*] - *incipient and shallow definite furcation invasions* - *flat or reverse architecture, tori, exostoses and ledges* - *bone contouring in conjunction with root resection* - *to achieve primary closure of flaps by thinning bone (osteoplasty), NOT removing attached bone (ostectomy)*

Diagnosing/evaluating osseous defects: *Radiographs*

- *can reveal the existence of angular bone loss in the interproximal space* - 2-dimensional information (*does NOT give us 3-dimensional information!!*) --> see IMAGE

What are the *CONTRAINDICATIONS for osseous resection*?

- *esthetic areas* - *isolated deep pockets* - *advanced periodontitis* - *patients with HIGH caries or plaque index* - *patients with a serious systemic condition* (Examples: uncontrolled diabetes or smokers, have trouble with wound healing) the presence of certain local anatomical factors such as: - *near the ascending ramus* (because difficult access to remove bone) - *near the external oblique ridge* (prevents you from hitting the mylohyoid muscle) - *in close proximity to the maxillary sinus* (risk of perforation) - *adjacent to a flat palate* (risk of hitting the greater palatine artery and nerve)

What are the *two types of osseous re-contouring procedures*?

- *osteoplasties* - *ostectomies*

What are some of the *DISADVANTAGES of osseous resection*?

- GREATER loss of attachment than other surgeries - esthetics is compromised especially in the maxillary anterior region - root hypersensitivity - root caries

What are some of the *ADVANTAGES of osseous resection*?

- MORE predictable than osseous regeneration - a minimal waiting period for healing - plaque control is EASIER with shallower probing depths than deeper probing depths

What is *vertical grooving*?

- REDUCES the thickness of the alveolar housing and provides relative prominence to the radicular aspect of the teeth - provides continuity from the interproximal surface onto the radicular surface --> see IMAGE

How are *bony defects classified*?

- THREE-wall infrabony defects - TWO-wall infrabony defects - ONE-wall infrabony defects

What are the various *objectives of osseous resection*?

- create bony contours that will PARALLEL gingival contours after healing with shallow crevice depths - create cleansable gingival contours - reshape the marginal bone to resemble the alveolar process undamaged by periodontal tissue (*positive architecture vs. negative architecture*) - permits easier primary wound closure by thinning bone and allowing better flap approximation - expose additional clinical crown for proper restoration (crown lengthening)

What is *radicular blending*?

- it attempts to gradualize the bone over the entire radicular surface - provides a SMOOTH surface for good flap adaptation --> see IMAGE

Describe *gradualizing marginal bone*:

- minimal bone removal - necessary to provide a sound, regular base for gingival tissue to follow

Describe the history of osseous resective surgery:

- originally performed to remove necrotic or infected bone - Kronfeld (1935) established that all bone is healthy - this was followed by historical studies on osseous surgery by the fathers of the periodontal speciality - created guidelines, terminology, definitions and treatment procedures presently used

What are the *5 therapeutic choices for osseous defects*?

1. *osseous recontouring (osteoplasties and ostectomies)* 2. *induce regeneration of bone (GTR)* 3. *root resection with osseous resection* (aka taking 1 root off of a maxillary/mandibular molar) 4. *maintenance of the pockets associated with osseous defects* (*NON-SURGICAL OPTION*, *open flap debridement may be done for areas of advanced bone loss* because this non-surgical approach prevents us from losing more bone) 5. *tooth extraction*

Additive therapy can be used for vertical bony defects. Can additive therapy (grafts) be used for horizontal bone loss?

NO

Are ALL pockets candidates for osseous surgery?

NO

Is the presence of an osseous defect itself a sign of disease?

NO, *the presence of an osseous defect itself is NOT a sign of disease*

Are the *bony deformities of osseous defects typically uniform*?

NO, *they are often a combination of horizontal and vertical loss*