|Periodontal Restorative Consideration 1
In this lecture we will discuss the relation of the restorative and periodontal therapy so we don’t end up with problems in the periodontal tissues like in the first picture case in slide 2.
In slide 3 here is another case, in which the margins all are apparent, in which the inflamed gingival tissue shrank after the treatment exposing all the restorative margins, or it might be gingival recession exposing the margins after they have been sub-gingival margins before the recession happened, but the teeth are short already so it is difficult to be of a recession cause.
Slide 11 rational for therapy:
Why do we need or we say that we need periodontal treatment before any restorative treatment?
Control periodontal active infection, we have residual effects of periodontal disease like bone loss, mobility, recession, persistent pockets, loss of architecture.
To prepare the periodontium for restorative dentistry like crown lengthening, bone grafts, soft tissue grafts.
So why do we start with periodontal treatment?
Slides 11, 12, 13: extra notes:
-Stable gingival margin is most important in esthetic areas (anteriorly which nowadays extend to premolars).
-To facilitate restorative procedures.
-One of the signs of periodontitis is pathological tooth migration, and we might have spontaneous repositioning of teeth after treatment.
Slide 14, 15: no extra notes.
Reevaluation of gingivitis is after 2 weeks.
In case of periodontitis reevaluation after 6-8 weeks, because the CT fibers reattach and heal after 6-8 weeks, and we can probe then.
But during this period there is a lot of things that you can do including caries control (fillings and temporary fillings), extractions and temporal bridges and RPDs, but remember it’s on a case by case bases.
Probing depth vs. pocket depth
Probing depth: how much the probe penetrates.
Pocket depth: is a histologic measure between the most coronal of gingival margin and the most coronal cell of junctional epithelium and it differs at least 0.5mm in healthy situations from the calculated using a probe.
Periodontal surgery whether it’s resective surgery like gingivectomy or osseous surgery
access surgery like flaps
regenerative surgery like bone grafts
Adjunctive orthodontic treatment like closure of diastemas, repositioning of teeth … etc
Patient’s comfort … if the patient cannot brush properly
Notice the probe exceeding the mucogingival junction, this is keratinized but not attached gingiva.
And it’s ok as long as he maintains adequate plaque control.
The chief complain could be esthetics or sensitivity
double pedicle graft
when you put a crown in an area of non-keratinized tissue it seems to have more failure rate because of plaque retention.
We have non-carious lesions on crown and root.
What we do is restoring the crown creating like-CEJ and graft up to it
Vertical ridge augmentation is less predictable and technically difficult than horizontal ridge augmentation but it’s doable.
After extraction we almost always have bone resorption, so we would have concavity under pontics
Immediate implant placement does not preserve the bone FOR SURE during the first 6 months; we are talking about the immediate.
The shrinkage is 50% horizontally post extraction.
This problem is more severe if occur in the anterior area.
This case is from the book >>> 2 prepared abutments & a post-extraction socket. How to preserve the ridge morphology post-extraction ???
they put a collagen sponge just to hold the tissue then (slide 35) they put the temporary bridge right away ... the temporary pontic enters 2mm inside the socket & has ovate upper border (as if the tooth is emerging from the socket not only saddle on top of the tissue), so the tissue will take the shape of the ovate pontic (slide 37).
You should use special impression techniques to capture the soft tissue profile because the original techniques focus on capturing the finish lines (not the soft tissues).
The final restoration (slide 38) doesn't look like a pontic, it looks like a tooth emerging from the socket. Note that the inter-dental papilla is still there because wt determine the level of the papilla is the level of inter-dental crestal bone at the adjacent tooth.
-if the distance between the contact point & the crest of the bone is 4.5-5 mm, papilla fill will occur in 100% of the cases.
-if you seat your crown & then you recognize a black triangle, what can u do ??? >>> you should measure the distance between the contact point & the crest of the bone, how ???
>>> By bone sounding ( give anesthesia insert the probe in the sulcus inter-dentally till u reach the base of the sulcus push the probe all the way till u touch the crest of the bone),
if the distance between the contact point & the crest of the bone is between 4.5-5mm there is a good chance for papilla fill (spontaneously).
if the distance >5mm we can change the position of the contact point to a higher position.
In this case, the patient wasn't happy with her proclined lower teeth (the 2 laterals). What options do we have here ??? Orthodontic treatment >>> the patient wasn't willing to do orthodontic treatment so we extracted the 2 laterals and prepared the canines and the centrals then we did ridge preservation (bone graft); to preserve the ridge shape and to avoid excess shrinkage (slide #41) then we seated the temporary bridge (slide #42).
Note that we didn't extend the temporary pontic inside the socket because if we did so, we would keep the gingival margin as it was before.
(slide #43) this picture is at the follow up stage, notice the staining on the
temporary bridge due to chlorhexidine mouth wash.
(slide #44) notice the ovate shape of the tissue at the pontic site after healing.
Finally (slide #45) we inserted the permanent bridge (this bridge is made of zirconia so the color matching isn't perfect).
Notice the neck of the right lateral incisor, we made its color more pinkish to improve the appearance and match the gingival level at the other side (because even after grafting, still there is some deficiency in the gingival margin).
Clinical crown lengthening procedures:
1) to provide retention form to allow for proper tooth preparation, impression procedure & placement of restorative margins .
2) to adjust gingival level for esthetic.
3) to preserve the biologic width.
The biologic width:
-is the physiologic dimension of the junctional epithelium and connective tissue attachment.
-in general it's about 2mm (+/- 30%).
-when do you invade the biologic width ???
>>> when you pass beyond the upper border of the junctional epithelium. So usually if you place your finish line 0.5mm into the sulcus, you are safe and not likely to invade the biologic width, but when you go deeper than that, the risk to invade the biologic width will increase.
-what is the problem with invasion of the biologic width ??? Bone loss, recession, pocketing, and in most cases constant inflammation (redness, bleeding …) will occur.
Note: the most likely place to invade the biologic width is the proximal area of the tooth and most of the time the end result of this is a constant inflammation.
Bone sounding can be used to determine the biologic width for a specific site (because of course there is an individual variation). How ??? Give anesthesia measure the probing depth (let's assume the PD=3) push the probe all the way to the crestal bone if the probe reading is 5mm then the biologic width = 5-3 = 2mm.
Contraindication of crown lengthening:
1-if surgery would create an un-esthetic outcome:
if the crown lengthening will result in gingival asymmetry specially in the anterior area (so it's usually contraindicated in the anterior area if it results in esthetic compromise). But if the patient is old, with low lip line and not very interested in his/her appearance then you can go for crown lengthening with compromised esthetic instead of doing orthodontic extrusion and complicated treatment.
2-deep caries or fracture would require excessive bone removal that might compromise either the same tooth or the adjacent teeth.
3-the tooth is a poor restorative risk:
example: tooth with bad RCT and the endodontic prognosis is poor.
4-significant invasion of the furcation area is anticipated (especially in molars).
Crown lengthening procedure:
-generally, we need 3mm between the bone crest and the planned location of the gingival margin. Why ??? Because we need 2mm biologic width and 1mm sulcus.
-crown lengthening could be accomplished by gingivectomy or flap with or without osseous re-contouring (but most of cases we need osseous re-contouring).
-How to determine that this patient needs gingivectomy alone and that pt needs flap ???
Depends on the distance between the location of the desired gingival margin and the crest of the bone >>> if this distance is >/=3mm then we can do crown lengthening with gingivectomy alone, but if <3mm then we go for flap.
for example (slide #52) if I have 5 mm between the gingival margin and the bone crest and I want to lengthen the crown 2mm (I need to cut 2 mm of the gingival margin), the distance between the new location of the gingival margin and the bone crest will be 3mm so I can go for gingivectomy alone.
But if I have 3 mm between the gingival margin and the bone crest and I want to lengthen the crown 2mm, the distance between the new gingival margin and the bone crest will be 1mm so I can't go for gingivectomy alone (I need to raise a flap).
Note: most of crown lengthening cases need flap with osseous re-contouring.
This patient is an African-American, she has part of the gingiva covering the teeth, we did gingivectomy (slide #54) because there is enough distance between the desired location of the gingival margin and the bone.
Here we need to raise a flap and remove bone, notice (slide #58) that the concavity of the furcation starts to become exposed.
When I raise a flap and cut bone, I can't leave some bone inside the furcation because this bone will either resorb or relapse). So you must determine howmuch bone to cut so as not to expose the furcation area.
-here we have restoration not invading the biologic width.
-this tooth needs a crown.
-we need our crown margin to go beyond the margin of the restoration, why ??? >>> To provide a ferrule effect, so we need the finish line to be at a sound tooth structure.
- to provide a ferrule effect in this case, we need to move everything apically (by crown lengthening).
-the ferrule effect is 1-1.5 mm, so we need at least 1mm of tooth structure for margin placement and retention.
we must take into consider the final position of the crown margin before doing the crown lengthening.3mm>