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
What is an aesthetic issue with may require soft tissue augmentation?
Black triangles
*What is the importance of contact points and embrasures in terms of interdental papilla and why?
How often does papilla fill the embrasure space if the the distance from contact point to crestal bone is =5mm, 6mm and 7mm?
Papillary height is established by the level of bone, the SCAT and the form of the gingival embrasure
Can prevent aesthetic issues → Black Triangles
- = 5mm → papilla always filled the space
- 6mm → 56% filled the space
- 7mm → 37% filled the space
*What happens if the gingival embrasure is too wide, the ideal width, and too narrow?
- Embrasure too wide → papilla flattens out, assuming a blunted shape
- Embrasure ideal width → papilla assumes pointed form, normal sulcus
- Embrasure too narrow → papilla grows out to the facial and lingual and becomes inflamed
What are the the non-surgical options to manage black triangles? (2)
- Tissue coloured ceramics (if doing fixed prosthetics) directly on the restoration to cover the black triangles
- Bring contact point of the teeth more apically toward the papilla
what are the 4 types of pontic design, and which of these is best baalnce for aesthetics + hygiene?
A. Hygienic
B. Ridge Lap
C. Modified Ridge Lap
D. Ovate
-Modified ridge lap is best balance for aesthetics + hygiene
What are the benefits of provisional prostheses prior to implants, and how should they be placed in relation to the soft tissues and the bone? (4,2)
- *helps to develop the emergence profile for implant-supported restorations
- Develops the ovate pontic receptor site
- maintains interdental papilla
- useful in single and multiple implant sites
-Placed at least 2mm away from bone, 1-1.5mm deep in the gingiva
Around root resected teeth, what is usually done?
??
Pt is wanting ortho tx to fix smile
What are some issues seen in this dentition
- generalised recession
- Supereruption of some teeth
- interdental papilla lost in some areas - bone loss
- some pathological migration
- some teeth missing
- proclined upper incisors
- AOB, etc
these are the radiographs from the same pt
What needs to be addressed before sending the pt for ortho tx?
Pt has generalised periodontitis, severe in some areas.
periodontal health needs to be managed before commencing ortho tx
- Periodontal treatment - stabilisation of bone loss, acquire healthy gingiva and plaque control
- Reassess after 4 months to confirm pt co-operation
- necessary Extractions and endodontic txs done
→ then commence ortho
What are the benefits of ortho tx in patients with perio? (6)
- Better oral hygiene by aligning crowded or malposed teeth
- Improvements of certain types of osseous defects can be achieved by vertical orthodontic tooth repositioning
- Improve the aesthetic relationship of the maxillary gingival margin before restorative dentistry
- Forced eruption to permit adequate restoration of fractured teeth
- Open gingival embrasures can be corrected
- improve adjacent teeth positioning before implants or tooth replacement
What is pathological tooth migration (PTM), and what are the major factors affecting tooth movement (3) and in which pts do you typically see PTM in?
-PTM is a change in tooth position due to a disruption of forces that maintain teeth in normal relationship
Major factors affecting teeth position:
- soft tissues (cheeks, tongue and lips) and Periodontal tissues
- Occlusal forces
- oral habits
-PTM is a significant finding in pts with severe perio
Example of pathologic tooth migration (PTM) treated with perio and ortho
What types of bone defect can orthodontics be used to help treat?
- hemiseptal bone defects
- Furcation defects
Where are hemiseptal defects found?
found in tipped teeth and supra-erupted teeth
(picture of hemiseptal defect due to mesially tipped molar treated by uprighting the molar)
how can bone level affect orthodontic bracket placement?
orthodontic brackets are placed to get the correct movement in the tooth dependent on the centre of rotation of the tooth → bone levels need to be considered when placing orthodontic brackets as the centre of rotation can vary
How may orthodontics be used in conjunction with periodontics to fix a furcation defect?
When hemisectioning of a Class II furcation defect is done, Ortho can be used to create some space between the two roots
A patient presents to you with a fractured tooth and you are considering undergoing Forced Eruption through orthodontics. What are factors you need to consider? (6)
- Aesthetics - high lip line
- Root Length - if fractured to the level of the bone, erupt at least 4mm, final root-to-c’rown’ ratio should be 1:1
- Root form - shape of root should be broad and non-tapering
- Level of the fracture - if the fracture is too deep, it will be difficult
- Importance of the tooth - consider pt age and costs
- Endo/perio prognosis
How can orthodontics be used to fix aesthetics?
Aligning teeth in an aesthetic position
A pt is planning to commence ortho tx and the Ortho referred the pt to you for a pre-tx periodontal screening. What do you assess in your periodontal risk assessment?
History:
- Previous periodontal disease
- Drug history
- Systemic diseases
Clinical examination:
- BOP
- mobility
- thin, fragile gingiva
- pocketing
*what determines the heigh of the interdental papilla (Eg. to prevent black triangles)
- Level of bone crest - SCAT - Shape of gingival embrasure
