Major Connectors

Dr. Mahmoud Ramadan

Definition:
The component of RPD which joins the parts of the prosthesis on one side of the arch to those on the opposite side.

Special structural requirements of Maxillary Major Connectors :
1- Intimate contact between the tissue side of the connector and the palatal tissues is required to enhance support, retention and stability of the partial denture. For this reason :
a- Relief is avoided under maxillary major connectors.
b- The tissue side of the connector should not be highly polished during the final finishing and polishing procedures.
c- Little relief may be only required in the presence of palatal tori or prominent median palatine raphe.
d- An effective specially prepared seal is required along all borders of maxillary major connectors that are in contact with soft tissues. This seal ensures intimate contact with the palatal tissues and prevents food debris from collecting under the connector. Beading of the maxillary cast is essential to develop this peripheral seal. This beading is prepared on the master cast by scrapping a shallow groove (0.5 mm in width and depth) along the borders of the connector.
2- All borders should be tapered slightly (beveled) towards the tissues so that they are less perceptible by the tongue. Borders should also be smoothly curved and should never be irregular.
3- The thickness of palatal plates should be uniform.

Review of Indications of Maxillary Major Connectors:
1- If the periodontal support of the remaining teeth is weak → more of the palace should be covered → A wide palatal strap or a complete palate is indicated.
2- If the remaining teeth have adequate periodontal support and little additional support is needed → a palatal strap or antero-posterior palatal bar may be used.
3- For long-span distal extension bases where rigidity is critical → an antero-posterior palatal strap or com¬plete palate is indicated.
4- When anterior teeth must be replaced → an antero-¬posterior palatal strap, complete palate, or horse¬shoe major connector may be used. The final se¬lection must be based on modifying factors such as:
a- number and location of missing posterior teeth.
b- periodontal support of remaining teeth.
c- type of opposing occlusion.
5- If a torus is present and is not to be removed → an anteroposterior palatal strap, antero-posterior palatal bar, or horseshoe major connector may be used.
6- A horseshoe connector should be used very spar¬ingly
7- A palatal bar is rarely indicated.

Special structural requirements of Mandibular Major Connectors :
1- Rigidity without produce excessive bulk.
2- Must not impinge upon the movable floor of the mouth, frenum or tori.
3- Require relief between metal and tissues for these factors:
a- For tooth supported edentulous areas: little or no relief is needed → denture doesn't tend to move in function.
b- For distal extension edentulous areas: moderate amount of relief → denture tends to rotate during function.
c- Slope of anterior ridge: if soft tissues slopes towards the tongue → greater amount of relief → prevent laceration on movement.
d- Undercut of anterior ridge: it should be blocked-out.
4- Beading lines not used with the friable mucosa of the mandibular arch.

Review for indications for mandibular major connector:
1- For tooth supported RPD → Lingual bar.
2- Insufficient room between floor of the mouth and gingival margins or large tori → Lingual plate.
3- Low periodontal support for anterior teeth → Lingual plate.
4- Low periodontal support for anterior teeth with wide embrasures → Step back design or double lingual bar.
5- Replacement of all posterior teeth → Lingual plate.
6- Labial bar is rarely indicated.

Download the complete Lecture

Doc. Format - 134 kb

http://4dent.net/url/1059