Kennedy classification RPD l Removable partial denture MCQs

Kennedy classification RPD l Removable partial denture MCQ (multiple choice question) for dental students 

 

Kennedy classification

Class I

• Bilateral edentulous area located posterior to remaining natural teeth

Class II

• unilateral edentulous area located posterior to remaining natural teeth

Class III

• Unilateral edentulous area between natural teeth located anterior and posterior to it

Class IV

• Single bilateral edentulous area ( crossing the midline) located anterior to remaining natural teeth

 

Applegate’s rules

1. Classification should follow and not precede extractions that might alter the classification
2. If a 3rd molar is missing and it will not be replaced it is not included in the classification
3. If a 3rd molar is missing and it will be an abutment it is included in the classification
4. If a second molar is missing and it will not be replaced , it will not be included in the classification
5. The most posterior edentulous area determines the classification
6. Edentulous areas other than those that determine classification are called modification spaces and they are designated by a number
7. The extent of the modification area is not important it is the number of modification areas is what is important
8. There is no modification for class IV

Treatment planning for RPD

Q: a patient comes in with an edentulous space what step do you take in tx planning?

1. Medical + dental history + Listen to the patient’s concern
2. Intraoral soft tissue examination + examine for available inter arch space
3. Evaluate the loss of vertical dimension ( specially in case of post tooth loss )
4. Examine the prognosis and periodontal status of the abutment teeth ( mobility, crown root ratio, presence of large caries or restorations etc.. ) Decide if any teeth need modifications ( recontouring, changing composites to amalgams in abutment teeth , dimpling, creating undercuts using composite, do any of the teeth need surveyed crowns?
5. Radiographs ( OPG + bitewings + PA for abutments )
6. Take primary impression for study casts for diagnosis , designing and surveying

 

NOTE:

• Dimpling:  creating undercuts on tooth surface to engage the terminal part of the retentive arms
• you ALWAYS seek specialist consultation with a referral letter.
• Referral letter should include: pt details, medical + dental history, reason for referral, what advice or tx do they suggest.

 

If the patient already had a previous RPD:

1- Check the RPD

• Color
• Hygiene
• Condition ( is it repaired or added to? How did it break ? how was it repaired? And when. )
• Design of the denture and it there are any abnormal wear patterns

2- Intraorally check

• Denture extensions + retention + stability
• Occlusion:  Check contacts in CR, CO, ICP and eccentric positions

 N.B: 

• if there are enough teeth remaining → restore the RPD in CO/ ICP
• If many teeth are missing → restore the RPD in CR (treat it as Complete denture )

Indication for cobalt chromium RPD :

1. Long edentulous span [ short spans → FPD or implants]
2. No posterior abutment [ distal extensions]
3. Several edentulous spaces
4. Excessive ridge resorption [ a bridge will not replace the resorbed ridge]
5. Splinting of periodontally weakened teeth ( a lingual plate that goes up to the cingulum will support anterior teeth that are not abutments)
6. Obturators
7. Patient desire

Q: what are the objectives of any treatment plan?

1. Manage and treat existing disease / condition
2. Prevent future disease
3. Restore function
4. Improve appearance

 

• advanced phase: endo , strategic extractions ( retained root , perio involved abutment ) , pre prosthetic surgeries, periodontal surgeries , orthodontics ( correction of tilted teeth )

 

So why we do we design the partial denture ? 

• Mainly to control movement (most important thing). because uncontrolled movements will end up with disastrous consequences on teeth and bone ,therefore we have to control them .

We have general and specific principles for RPD design:

     

Only treatment indicated cases.

• Ex. A man only lost his upper/lower five for a long time with other manifestation as over eruption for the opposite teeth and tilting of the adjacent tooth ,so do not put an RPD there and do not convince your patient to have an RPD !! the case should be indicated before you start your treatment.     

Try to save marginal gingiva

•  When you put a minor connector do not put them between the teeth so you wedge them & this will lead to periodontal problem.
• In addition, major connector should be away from teeth and gingiva; so it only covers the necessary area.
• Remember that we have many design for each case ;but the main issue is to reduce forces on teeth and mucosa ( bone)

 

How can we reduce the forces?

•       Dissipate the forces  on more abutments 
•       Make the force (clasp tip) as cervically as possible ,also should be free (not touching  the gingiva),0.5-1 mm at least 
•       Reduce the size of occlusal table 
•       Put the teeth in the neutral zone 
•       Break the stress