MS2 - Interdisciplinary perio 1 (Restorative and Ortho) Flashcards
Learning outcomes
- understand the basic concepts and rationale around interdisciplinary periodontics
- Understand the concept of biologic width and its role in restorations
- Describe the various options for crown lengthening procedures
- Understand the adjunctive role of orthodontic procedures during management of periodontal disease
What is the rationale of conducting periodontal therapy prior to restorative and orthodontic work?
To have non-inflamed, healthy tissues which are less likely to chance as a result of sub-gingival restorations
- **Stable gingival margins before tooth preparation
- adequate tooth length
- Perio tx after orthodontic tooth movement may change tooth position
- Successful aesthetics and implant procedures need specialised periodontal procedures
What is the sequence of events of periodontally preparing a pt for restorative or orthodontic tx?
- Emergency tx
- Extraction of hopeless teeth
- OHI and education
- Scaling and root planing
- Re-evaluation
- Perio surgery (if required)
- Adjunctive ortho therapy (if required)
What is the basic sequence of treatment when preparing a pt’s periodontium pre-prosthetically?
- management of mucogingival problems
- Preservation of ridge morphology after tooth extractions
- Crown-lengthening procedures
- Alveolar ridge reconstruction
What is the issue here and what has been done + why?
periodontal pocket extending beyond mucogingival junction
-increased width of attached gingiva by free-gingival graft
How may you preserve ridge morphology after an extraction?
By NOT compressing the socket after an extraction to preserve the ridge dimensions
→ sometimes bone grafts are placed into the extraction sockets to keep the dimensions and provide a 3D template for new bone to form into it
What are the 3 types of restorative margins in relation to the gingiva and what effect do each have on the gingiva?
- supra-gingival → Least effect on the periodontium (may be unaesthetic for anterior teeth)
- Equigingival → well tolerated
- Subgingival → Can affect gingival tissue (SCAT)
*What is SCAT, what exactly is the most common height of this and what is the recommendation for restorative margin heights?
Supra-crestal attached tissues (biologic width)
SCAT = junctional epithelium (JE) + supra-crestal connective tissue attachment (SCTA)
-2.04mm is the most common height of SCAT
–3mm from the bone crest is the recommended, as healthy gingiva will have a sulcus of approx. 0.69mm (making the distance from bone crest to gingival margin 2.73mm)
How can you measure / check whether the SCAT has been invaded after a restoration and which is the most accurate way in the clinical setting? (4)
- *“sounding to bond” → sterile perio probe pushed through the attachment tissues from the sulcus to the underlying bone under anaesthesia - Can ONLY be done on healthy gingiva (inflamed gingiva will have skewed measurements >2mm reading at one or more locations = SCAT violation
- Radiographic interpretation can SUGGEST inter-proximal violations of SCAT
- Pt discomfort when the restorative margin levels are being probed indicates SCAT
- Histological assessment (not clinically possible)
If the SCAT is violated, or if you are anticipating violating it (eg. subgingival caries), what are the management options? (2)
Which of these approaches achieves the outcomed faster and when may you consider each?
- surgically removing bone away from the proximity to the restoration margin, or
- Orthodontically extruding the tooth, this moving the restorative margin away from the bone
-surgical approach achieves outcome faster → if you don’t have much time (eg. done within a few weeks), can do surgical. If it a more long term plan (months), ortho extrusion is an option
What are the guidelines of clinical margin placement? (3)
Rule 1: Sulcus =1.5mm - restoration margin no more than than 0.5mm below gingival tissue crest
Rule 2: Sulcus 1.5-2mm - margin at half the depth of the sulcus below tissue crest
Rule 3: Sulcus >2mm - gingivectomy to lengthen the teeth and create a 1.5mm sulcus, then follow Rule 1
What is crown lengthening, what is the aim, what are the indications and contraindications? (1, 1, 3, 3)
-Surgical procedure to expose adequate clinical crown to prevent placement of restorative margins in SCAT
Aim: at least 3mm between the most apical extension of the restorative margin and alveolar bone
Indications:
- Subgingival caries or fracture
- inadequate clinical crown length for retention
- Aesthetic reasons - unequal or unaesthetic gingival heights
Contraindications
- Aesthetics - if surgery would create unaesthetic outcome
- Deep caries / fracture would require excessive bone removal on contiguous (adjacent ) teeth
- the tooth is a poor restorative risk
When would you do soft tissue crown lengthening vs osseous reduction crown lengthening?
>3mm soft tissue → soft tissue crown lengthening
<3mm soft tissue → crown lengthening with osseous reduction
(extra)
When you remove bone during crown lengthening, how should the flap be displaced when being put back?
since the bone height has been reduced, should have an apically reduced flap
When would you consider using orthodontic extrusion (2) and what are the two types of orthodontic extrusion, their time period and the required treatments alongside ortho?
- violation is on the interproximal side
- violation is across the facial surface with ideal gingival tissue levels
- Slow force (months) - bone + tooth move → required osseous reduction after tx
- Rapid force (weeks) - tooth movement only → requires supracrestal fibrotomy every few weeks to allow tooth to move easily