1. Rest = part of RPD = rigid extension of the RPD – provides support. 
2. Rest Seat = Prepared on abutment teeth
3. Functions: 
   1. Directs and distributes occlusal force apically to abutment teeth 
   2. Acts as vertical stop = doesn’t allow RPD to move in the tissue-ward direction
   3. Maintains retentive clasp in position = SUPPORT in RPD
   4. Rest do allow slight movement = dissipates horizontal forces
4. TYPES
   1. PRIMARY = part of the clasp assembly 
   2. SECONDARY/AUXILLARY = indirect retention
      

OCCLUSAL 

1. Shape = ROUNDED TRIANGULAR
2. Base = Margin of tooth 
3. Apex = center of tooth
4. Floor = spoon-shaped
5. Dimensions = 1/3rd to half of M-D diameter of tooth and ½ of B-L diameter of the entire tooth 
6. Measured from cusp tip of buccal side to cusp tip of lingual side. (draw)
7. ACUTE angle = floor is inclined to towards center of tooth and angle is less than 90* = hence, Increases the support (draw)
8. If an obtuse angle is present, it causes Slippage of the prosthesis = therefore, avoiding the inclined plane effect 
9. Occlusal rest = 0.5mm thick at the thinnest point 
10. 1-1.5 mm = when it crosses the marginal ridge
11. We use diamond or carbide round burs with water and light pressure 
12. Preparation is done entirely on enamel only
13. If the rest seat needs to be placed away from the edentulous area→it is not flared to the facial line angle and should be more flared lingually ( to provide space for minor connector)  
14. Interproximally extended occlusal rest seat:
    1.  Flared more buccally and lingually without affecting the contact area 
    2. U shaped trough that is 1mm wide and 1 mm deep 
    3. Without breaking the contact = Use a shoulder bur to create a 1 mm Buccolingual clearance from the proximal side then use a round bur to create the seat 
15. In RPA with intracoronal occlusal rest seat
    1. A partial denture that is totally tooth supported by means of cast retainers on all abutment teeth may use intracoronal rests for both occlusal support and horizontal stabilization
    2. Open the margins more and do slight lingual flaring for the minor connector
16. Extended occlusal seat rest
    1. In Kennedy Class II, modification 1, and Class III situations in which the most posterior abutment is a mesially tipped molar
    2. an extended occlusal rest should be designed and prepared to minimize further tipping of the abutment and to ensure that the forces are directed down the long axis of the abutment.
    3. This rest should extend more than ½  the MD width of the tooth and 1/3 rd the B L width of the tooth
    4. 1mm thickness of metal = the preparation should be rounded with no undercuts or sharp angles 

LINGUAL REST/CINGULUM REST

1. Only for maxillary canine 
2. The mandibular canine is avoided as it lacks the bulk of enamel. 
3. V-shaped = boomerang shape – Cross section view 
4. Cresant/Half moon shape – Lingual view
5. Dimensions = 2.5mm M-D to 2mm B-L 
6. Depth = 1.5mm = as average thickness of enamel is 2 mm

INCISAL REST 

1. Mandibular canines and rarely incisors 
2. V-shaped notch = 1.5 – 2mm away from the proximal incisal angle
3. Purpose = functioning as secondary rest for indirect retention
4. Dimensions = 1.5mm wide, 1.5 mm deep, and 1.5mm away from the proximal incisal angle
5. If multiple incisal rests are needed = rests are connected with linguloplate i.e Choice of major connector
6. Lingual rest are more commonly preferred than incisal= as lingual rest will be very close to the rotational center of tooth = Bear loads in a much better manner than incisal rest
7. Major problem = Anterior zone are aesthetic zones. Hence, lingual is chosen over incisal. 

EMBRASSURE REST 

1. B-L = 3-3.5mm wide
2. Depth = 1.5mm – 2mm deep
3. If not met = definite chances of fracture of RPD components. It is very difficult to fix it with the same strength of RPD design 

1. Each retentive arm should be opposed by a reciprocal component capable of resisting any orthodontic pressure exerted by the retentive arm 
2. Functions of reciprocal arm 4m*
   1. It provides stabilization/reciprocation against the action of the retentive arm.
   2. It also stabilizes the denture against horizontal movements.
   3. The reciprocal arm may act as an indirect retainer to a certain extent, i.e. when it rests on a supra-bulge surface of an abutment tooth lying anterior to the fulcrum line.
3. Design specifications for a reciprocal arm 
   1. It is positioned on the side of the tooth opposite to the retentive arm. 
   2. The reciprocal arm must be rigid and should not be tapered. 
   3. It is positioned on a tooth surface that is reasonably parallel to the denture’s path of insertion and withdrawal.
   4. It is ideally located at the junction of the gingival and middle third of the abutment tooth. 

Some special reciprocal elements 

1. At times, linguoplate can be used to provide reciprocation.
2. Sometimes, an occlusal rest positioned on the opposite side of the tooth will provide reciprocation.

1. Swing-lock RPDs are used, when a number of remaining teeth is too few to support a conventional design. 
2. This denture has a labial bar extending labially all along the arch like a major connector. 
3. The labial bar is connected to the remaining parts of the denture by a hinge on one side and a lock on the other. 
4. The labial bar can be unlocked during insertion and locked after insertion. 
5. Indications 
   1. Missing key abutments 
   2. When the number of remaining natural teeth is less 
   3. When the remaining teeth are too mobile to serve as abutments 
   4. When the soft tissue and the tooth are in unfavorable contours 
   5. Provide retention and stability for maxillofacial prostheses, such as obturators 
   6. For retention of the prosthesis in case of loss of large segments of teeth and alveolar ridge, due to trauma or infection. 
6. CONTRAINDICATIONS
   1. When the vestibule is shallow 
   2. High labial frenal attachment 
   3. Patient with poor oral hygiene 
7. Advantages 
   1. The construction is relatively simple and inexpensive. 
8. Disadvantages 
   1. It is unaesthetic in patients with short lips. 
   2. Tipping is seen in the remaining anterior teeth in the distal extension case. 

Fabrication 

1. Selection of metal for swing-lock framework
   1. The metal of choice is chrome alloy. 
   2. Gold alloys wear off due to constant movement
2. Surveying and designing 
   1. The cast is mounted on the surveyor. 
   2. The path of insertion is from a lingual direction with the labial arm open. 
3. Lingual plate
   1. The lingual plate should be designed to end above the survey line. 
   2. It prevents the tissueward displacement.
4. Occlusal rest 
   1. helps to prevent tissueward displacement of the denture. 
5. Major connector 
   1. The mandibular major connector extends above the survey line with scallops extending up to contact points. 
   2. The maxillary major connector is the complete palatal or closed horseshoe with borders extending up to or above the survey line. 
6. Labial arm design 
   1. The vertical projection of the labial bar should be designed to touch the teeth below the height of contour. 
7. Conventional design
   1. This consists of a labial bar with metallic vertical I-bar or T-bars attached to it.
   2. Using acrylic resin retention loop 
   3. This is indicated for patients with short lips and where aesthetics is of concern. 
8. Selection of impression material = Heavy-bodied alginate is best preferred. 
9. Tray selection = A custom tray should be used for recording maximum labial and buccal vestibular depths.
10. For the secondary impression, 5–6 mm space should be given between the teeth and the tray when placed in the mouth. 
11. Making the impression. 
    1. It is similar to conventional dentures. 
    2. Dual impressions may be required for distal extension.
12. Framework fabrication.
13. Fitting the framework.
14. Arranging artificial teeth to occlusion 
15. Insertion = Lingual path of insertion is done. 
16. Post insertional care = Oral hygiene should be maintained by the patient. Distal extension RPD has to be frequently relined. 

1. In this technique, the secondary impression is made
   after the construction of the metal framework and denture base. So, it is referred to as functional reline.
2. By using this technique, a new surface is added to the
   tissue side of the denture base.
3. This can be done before insertion or later if excessive resorption is present.
4. Procedure 
   1. A soft metal spacer (Ash No. 7 metal) is adapted over the ridge on the cast before the metal denture base is being processed.
   2. After processing, the metal is removed, which leaves an even space between the base and the edentulous ridge.
   3. Border molding is done and an impression is made using a low-fusing modeling plastic placed over the tissue surface of the denture base.
   4. The modeling plastic is tempered in a water bath and seated in the patient’s mouth until an accurate impression of the ridge is made.
   5. The patient should partially open his mouth during the entire procedure.
   6. After modeling plastic application is complete, about 1 mm of modeling plastic is scraped away uniformly from all over the crest of the ridge.
   7. The final impression is made with a free-flowing zinc oxide eugenol impression paste. In cases where excessive undercuts are present, elastomeric impression material is used.

Disadvantages 

1. Occlusion may be altered after the new denture base is processed.
2. Previous occlusal contacts cannot be established.
3. May be difficult to maintain the correct relationship between the framework and the abutment teeth during the impression procedure.

1. Main complexity is to achieve natural occlusion 
2. One arch is natural = some wear and tear, crowns and fillings will be present. 
3. Sometimes, Natural teeth = maloppsed, tipped 
4. Probility = not good smooth or uneven occlusion plane seen in fabricated denture
5. This will destablize the denture and ride resorption is faster 
6. Acyrlic teeth = FAST wear and tear 
7. Porcelain teeth results in the wear of the natural teeth. 
8. Most preffered teeth = teeth with metal occlusion
9. Types
   1. SCD opposing natural teeth. 
   2. SCD opposinga(pre-existing)complete denture
   3. SCD opposing a removable partial denture. 
   4. SCD opposing an overdenture. 
10. PROBLEMS
    1. A mandibular SCD opposing upper natural teeth is extremely complicated. 
       1. The reduced surface area of the lower ridge results in excessive forces on the ridge resulting in rapid bone resorption. 
       2. The lower SCD is therefore rarely indicated. 
    2. The upper SCD opposing lower natural anterior teeth often results in the combination syndrome sequence 1 
       1. Excessive load on the anterior region of the complete denture 
       2. Ridge resorption in the maxillary anterior region. 
       3. Epulis fissuratum is formed at the maxillary labial sulcus 
       4. Downward movement of posterior plane of occlusion producing excessive resorption of the mandibular posterior region
       5. Downward tilting of the occlusal plane in the posterior region produces an anterior openbite which leads to supraeruption of the lower anteriors. 
       6. This increases the load on the anterior region of the upper denture producing a vicious cycle 
    3. Combination syndrome type 2
       1. Ridge resorption in the mandibular edentulous area 
       2. Downward movement of the posterior part of maxillary denture and the formation of flabby tissue
       3. Supra-eruption of lower anteriors
       4. Increased load in the anterior maxillary region of the complete denture 
       5. Resorption in the anterior portion of maxillary ridge and the formation of flabby tissue 
    4. The fixed position of lower anterior natural teeth gives us less flexibility for aesthetic placement of upper natural teeth.
    5. Fracture of the SCD is a common problem, especially if opposed by natural teeth, because of the forces generated by the natural teeth. 

1. Denture over retained teeth 
   1. Tooth supprted conventional overdenture 
   2. Tooth supported immediate complete overdenture 
2. Procedure 
   1. Teeth are removed
   2. Impression of Coping with wax
   3. Coping with metal is made
   4. Impression with coping marks
   5. Denture is fabricated 
3. ADV 
   1. Maintaing alveolar bone 
   2. Proprioception 
4. Ball attachemnt or stud attachment over denture 
5. 
6. These areas where teeth = less bulk of acrylic in the denture = this is prone to fracture 
7. Border moulding – jaw relation = exact procedure of CD
8. Over denture have HIGHER retention

1. Teeth are extracted and on the same day = denture is inserted
2. We are placing denture on bone that has not be resorped yet
3. After extraction = bone resorption is high 
4. Hence, relining at 5th months and 10th month 
5. First phase of resorption completed at 5th month
6. Second phase of resorption completed at 10th month
7. TYPES
   1. CID = conventional immediate denture
      1. Posteriors are extracted first 
      2. Anterior are extracted on the day of denture insertion 
      3. 
   2. IID = interim immediate denture 
      1. All teeth are extracted on same day 
      2. This denture needs to be changed after 12 months 
      3. Recontruction of a new denture is MUST.
      4. Relining is NOT done 
   3. All immediate dentures = not to be removed for first 24 hours = due to swelling = entire denture will be tight 
   4. 
   5. Adv = pt doesnt not stay without teeth even for a day 
   6. Disadv = anterior try in is not possible 
   7. All cases of immediate dentures case 
      1. Denture is fabricated first 
      2. Then extractions are performed 
   8. Special type = JIFFY DENTURE
      1. Type of interim immediate denture
      2. Made up of self cure resin 
      3. Not permanent 

1. Mc reason = bone resportion occurs as denture takes support from bone and tissue = after some time = denture will become loosely fit
2. Only done when occlusal contacts are proper 
3. RELINING = 
   1. Tissue changes are minimum 
   2. It means to resurface the tissue surface of denture to improve FIT 
   3. 
4. Rebasing 
   1. Tissue changes are maximum 
   2. Extreme version of relining 
   3. More material is needed for refitting 
5. If both maxilla and mandible needs reline or rebase 
   1. Maxillary procedure is done first 
   2. Cause Max denture maintains the occlusion plane
   3. 
6. RELING PROCEDURES

CLINICAL	LAB
STATIC = open or closedFunctional relineChairside	Articulator methodJig method Flask method

7. OPEN MOUTH TECHNIQUE
   1. Given by boucher 
   2. Impressions made independently 
   3. Max and mand impression separately 
   4. Not using any existing occlusion
   5. Denture of the pt= used as impression tray 
   6. Material = ZnOE
8. CLOSED MOUTH 
   1. Impression material is placed on intalglio surface of denture 
   2. Place in pt mouth
   3. Ask pt to bite = functional pressure while recording 
   4. Problem
      1. It doesnt record tissues at rest 
      2. How to determine the amount of pressure needed? Pt is biting and pt doesnt know how much pressure to be applied = Pressure variation 
      3. Impression material might move before the material sets
      4. Hence, Lab remounting of denture become extremely necessary  
9. FUNCTIONAL METHOD
   1. Dentures are not sent to the lab 
   2. Soft liner or tissue conditioner is used as impression materials
   3. After 3- 5 days of using soft liner = you take Final impression is when there is ABSOLUTE NO INJURIES = soreness and ulcers are healed in the pt
   4. Chairside = acrylic chemical cure must not be used = they might burn mucosa due to heat generation 
10. SOFT LINERS/ TISSUE CONDITIONERS
    1. Shock absorber 
    2. This shock is energy transmitted to the denture bearing areas or ridge during mastication 
    3. Short term soft liner 
       1. is called TISSUE conditioner  2m***
       2. Self curing or chemical cure 
       3. After 7 days, you MUST remove the material 
       4. It will absorb and interact with saliva 
       5. Hence, it will loose its property of elasticity 
    4. Plasticized acyrlic = 
       1. long term soft liner 
       2. Good bond between acyrlic denture and acylic liner
    5. Silicone elastomers
       1. No acyrlic 
       2. Rubber base material 
       3. Adv = good tissue adaptation 
       4. Doesnt form Good bond with acyrlic denture
       5. More prone to fungal infections  

1. First line of treatment 
   1. Educate the pt 
   2. Discontinue wearing dentures 
   3. Gels 
2. Denture stomatitis 4m***
   1. TYPE 1
      1. Localized type
      2. Same as sore mouth 
      3. Cause 
         1. Trauma 
         2. Localized infection 
      4. Pinpoint redness or hyperemia 
      5. 
   2. TYPE 2
      1. Erythematous type
      2. Generalised diffuse appearance
      3. Type 2 and 3 are always associated with plaque accumulation
      4. 
   3. Type 3 
      1. Also called Granular denture stomatitis 
      2. Involves hard palate and alveolar ridges
      3.  
   4. Candida associated denture stomatitis
      1. MC seen in diabetic pts 
      2. Mycelia present in the smear
      3. Presence of angular cheilitis 
      4. Higher risk for diabteic pt 
   5. Inflammatory papillary hyperplasia 
      1. Advanced stomatitis 
      2. This is a cancerous growth 
      3. Benign lesion = nodular 
      4. Not more than 2 mm in size 
      5. Location = hard palate 
3. SORE SPOT 4m***
   1. It means small ulcers
   2. They usually develop within 1 to 2 days after placement of new dentures. 
   3. They are small, painful lesions covered with a grey necrotic membrane and surrounded by an inflammatory halo with firm, elevated borders. 
   4. Etiology 
      1. Due to unbalanced occlusion 
      2. Due to overextension of flanges like in frenum region
      3. Due to bony spicule impingement
      4. Immunocompromised drugs
   5. Fleeting painful sores = Short term sore spot  
   6. Treatment 
      1. In normal patients, these ulcers heal within a few days after correcting the dentures. 
      2. If no treatment is administered, it may progress to denture irritation hyperplasia. 
4. EPULIS FISSURATUM 2m**
   1. Also known as denture irritation hyperplasia 
   2. Because of unstable denture = lot of load and trauma on denture bearing areas
   3. It is a hyperplastic reaction of the mucosa occurring along the borders of the denture. 
   4. Symptoms 
      1. flaps of hyperplastic connective tissue. 
      2. Deep ulcerations, fissuring and inflammation may occur at the depth of the sulcus. 
   5. The lesions usually subside after surgical excision of the tissues and correction of the dentures.
   6. Recurrence is rare. 
   7. These lesions may produce severe lymphadenopathy mimicking a neoplasm. 
5. BURNING MOUTH SYNDROME 4m***
   1. Difficult to identify the main cause
   2. As there is No visible changes in oral mucosa
   3. Pain starts in the morning and aggravates during the day.
   4. Burning sensation is usually accompanied with dry mouth and persistent altered taste sensation.
   5. Local factors 
      1. Mechanical irritation caused by ill-fitting dentures.
      2. Constant excessive friction on the mucosa.
      3. Candidal infections and allergic reactions can
         produce symptoms similar to BMS.
      4. Myofascial pain.
   6. Systemic factors
      1. Vitamin and iron deficiency
      2. Xerostomia
      3. Menopause
      4. Diabetes
      5. Medication.
   7. Psychogenic Factors
      1. Anxiety
      2. Depression
6. Treatment
   1. Generally BMS patients are more psychologically affected. 
   2. They consider that their psychiatric disorders are due to poor dentures. 
   3. These patients may need counselling to understand the irrelevance of the dentures with regard to their mental health and also to eliminate their fears. 
   4. The patient’s symptoms are given first priority.
   5. Soft Tissue conditioners 
   6. Remake new denture or relining/rebasing the denture