Major connectorsMarch 19, 2004

Sunhong Hwang DDS

Components of a typical removable partial denture

Major connectors Minor connectors Rests Directs retainers Stabilizing or

reciprocal components

Indirect retainers Denture bases

Major connectors 란 ? The component of the partial denture

that connects the parts of the prosthesis located on one side of the arch with those on the opposite side.

국소의치의 모든 구성요소가 직간접적으로 결합되어 있다 .

Cross-arch stability-functional stress 에 저항하는데 돕는다 .

Rigidity is eveything Flexing, torque 가 지대치로 가해지는 것

차단 Major connector 가 flexible 할 경우

발생할 수 있는 문제1. Jeopardize the supporting structure ex) Traumatic damage to periodontal support of

abutment teeth,Injury to residual ridges, and Impingement of underlying tissues

2. Be a detriment to the comfort of the patient

Location of major connector Guidelines in mind when the major connectors are designed and located with;

1. Major connectors should be free of movable tissues

2. Impingement of gingival tissues should be avoided

3. Bony and soft tissue prominences should be avoided during placement and removal.

4. Relief should be provided beneath a major connector to prevent its settling into areas of possible interference, such as inoperable tori or elevated palatal median sutures.

5. Major connectors should be located and/or relieved to prevent to prevent impingement of tissues as the distal extension denture rotates in function

Planned relief beneath the major connector

주연결장치가 닿아서 조직이 눌릴 경우 조직손상 (tissue damage) 이 발생한다 . 이를 미리 방지하기 위하여 relief 을 해준다 .

Planned relief 를 적절히 시행 못 했을 경우 생기는 문제점

1. 이를 조절 하기 위해 major connector 를 grinding 하는데 시간을 소모한다 .

2. Major connector 의 rigidity 를 약화 시켜서 파절의 위험이 생긴다 .

* 참고 * relief 완압緩壓 : 의치상 하부의 특정 부위에 미치는 부적절한 압력이나 힘을 제거 또는 약화시키거나 , 인상용 트레이 내에 인상재를 위한 공간을 만드는 것 .

Relief 가 필요한 부위1. Beneath lingual bar connectors or the bar portion of

linguoplates when indicated.2. Areas in which major connectors will contact the thin tissue,

such as hard areas so frequently found on lingual of mandibular ridges and elevated median palatal raphes

3. Beneath framework extensions onto ridge areas for attachment of resin bases

Relief 가 필요한 부위1. Beneath lingual bar connectors or the bar portion of

linguoplates when indicated.2. Areas in which major connectors will contact the thin tissue,

such as hard areas so frequently found on lingual of mandibular ridges and elevated median palatal raphes

3. Beneath framework extensions onto ridge areas for attachment of resin bases

Relief 가 필요한 부위1. Beneath lingual bar connectors or the bar portion of

linguoplates when indicated.2. Areas in which major connectors will contact the thin tissue,

such as hard areas so frequently found on lingual of mandibular ridges and elevated median palatal raphes

3. Beneath framework extensions onto ridge areas for attachment of resin bases

일반적 고려사항1. Margins of major connectors adjacent to gingival tissues should be

located far enough from those tissues to avoid any possible impingement ex) lingual bar 의 상부는 gingival margin 에서 4mm 하방에 위치 하부는 height of the moving tissues in the floor of the mouth 에 의해 제한

될 경우 linguoplate, sublingual bar, cingulum bar 가 선택된다 . Palatal connector 의 border 는 free gingival margin 에서 6mm 떨어져야 하고

gingival margin 의 형태에 따라 평행하게 형성한다 . 2. Palatal connectors ordinarily require no relief except for a palatal torus

or prominent median palatal suture area.---the presence of firm submucosal connective tissue and an adequate, deep blood supply.

주연결장치와 지지조직 사이에 밀접한 접촉이 이루어지면 , 의치의 stability, retention, support 에 도움이 된다 . Gingival area 는 제외된다 .

3. An anterior palatal strap or the ant. Border of a palatal plate should be located as far posteriorly as possible to avoid interference with the tongue in the rugae( 구개추벽 ).

4. It should be uniformly thin or straplike, rather than half-oval, and located so that its anterior border follows the contours between crests of the rugae.

5. The posterior limitation of a maxillary major connector should be just anterior to the vibrating line. Hard palate

일반적 고려사항1. Margins of major connectors adjacent to gingival tissues should be

located far enough from those tissues to avoid any possible impingement

ex) lingual bar 의 상부는 gingival margin 에서 4mm 하방에 위치 하부는 height of the moving tissues in the floor of the mouth 에

의해 제한 될 경우 linguoplate, sublingual bar, cingulum bar 가 선택된다 . Palatal connector 의 border 는 free gingival margin 에서 6mm

떨어져야 하고 gingival margin 의 형태에 따라 평행하게 형성한다 .

일반적 고려사항2. Palatal connectors ordinarily require no relief except for a

palatal torus or prominent median palatal suture area.---the presence of firm submucosal connective tissue and an adequate, deep blood supply.

주연결장치와 지지조직 사이에 밀접한 접촉이 이루어지면 , 의치의 stability, retention, support 에 도움이 된다 . Gingival area 는 제외된다 .

Mucous membraneMucosa: stratified squamous epithelium+ lamina propria(narrow layer of CT)Submucosa: 다양한 형태 dense to loose areolar tissue glandular, fat, muscle cells mucosa 에 blood, nerve 공급 periosteum 에 부착Submucosa 의 thickness 와 consistency가 support 에 중요한 역할Thin submucosa

Adipose tissue Glandular tissue

Dense collagenous fibersLoose CT and elastic fiber

일반적 고려사항3. An anterior palatal strap or the ant. Border of a palatal plate should be

located as far posteriorly as possible to avoid interference with the tongue in the rugae( 구개추벽 ).

4. It should be uniformly thin or straplike, rather than half-oval, and located so that its anterior border follows the contours between crests of the rugae

일반적 고려사항5. The posterior limitation of a maxillary major

connector should be just anterior to the vibrating line. Hard palate

A rule to be used throughout partial denture design

1. Try to avoid adding any part of the denture framework to an already convex surface.

2. Try to use existing contours and embrasures for the location of component parts of the framework.

3. All components should be tapered where they join convex surfaces

Characteristics of major connectors contributing to the maintenance of health of the oral environment.

1. Made from an alloy compatible with oral tissues2. Rigid and uses the principles of broad distribution of

stress3. Does not interfere with and is not irritating tongue4. Does not substantially alter the natural contour of the

lingual surface of the mandibular alveolar ridge or of the palatal vault

5. Does not impinge on oral tissues when the restoration is placed, is removed, or rotates in function

6. Covers no more tissue than is absolutely necessary7. Does not contribute to the retention or trapping of food

particles8. Has support from other elements of the framework to

minimize rotation tendencies in function9. Contributes to the support of the prosthesis

Mandibular major connectors Six types of mandibular major connectors1. Lingual bar2. Sublingual bar3. Lingual bar with cingulum bar(continuous

bar)4. Cingulum bar(continuous bar)5. Linguoplate6. Labial bar

Lingual bar Half-pear shape; the superior border of a lingual bar

should be tapered toward the gingival tissue with its greatest bulk at the inferior border

Made of reinforced 6-gauge, half-pear-shaped wax or a similar plastic pattern and 24-gauge casting wax(rigidity 을 위해 보강해준다 )

Located above moving tissues but as far below the gingival tissues as possible( 하연이 기능시 방해가 안되면서도 , 음식물이 끼지 않도록 , 혀의 위치에 방해 안되는 위치가 요구된다 .)

Lingual bar

Two methods to determine the height of the floor of the mouth

1. Periodontal probe 를 사용하는 법 치은연에서 구강저까지의 거리를 측정하여

진단모형에 기록한 후 , 구강형성 후 제작된 주모형에 표시한다 . 혀를 상순의 vermilion border 에 가볍게 접촉한 거리를 측정한다 ..

less variable and more clinically acceptable

2. Individual tray 을 이용한 인상 채득 거상시킨 구강저보다 3mm 짧게 한 개인용 트레이로

인상채득한다 . 이때 혀를 상순의 vermilion border 에 가볍게 접촉한다

Sublingual bar1. Lingual bar 를 사용할 공간이 부족한 경우 (6mm 이하의

공간이 있는 경우 )2. 형태는 lingual bar 와 같고 , 위치는 보다 후방 , 하방에

놓인다 . 구강저에 수평으로 놓인다 .3. Linguoplate 가 사용되는 곳에 대신 사용될 수 있다 .( lingual

frenum 에 방해 안되고 , llingual undercut 이 있는 곳에 사용됨

4. Contraindication; lingual tori, high attachment of a lingual frenum, interference to elevation of the floor of the mouth during functional movements.

Cingulum bar(continuous bar)

1. When a lingual plate or sublingual bar is otherwise indicated but the axial alignment of the anterior teeth is such that the excessive blockout of interproximal undercuts would be required

2. 위치는 전치의 cingulum 상에 놓인다 .3. Lingual bar 와 함께 사용될 수 도 있다 .4. 전치가 심하게 설측 경사 진 경우 , 전치부 spacing 이 있는

경우 심미적으로 문제가 있다 . 이 경우 상대적으로 linguoplate 보단 금속 노출이 적다 .

5. 3mm 넓이의 얇은 금속 판의 형태이다 .6. 인접한 주 지대치에 rest 를 부여하고 이곳에서 시작된다 .

Cingulum bar(continuous bar)

Linguoplate If the rectangular space bounded by the lingual bar,

continuous bar, and the bordering minor connectors is filled in, a linguoplate results.

형태 ; 1.thin 2. 치아와 embrasure 의 형태를 따른다 . 3.upper border- not straight but curved to follow the

natural curvature of the supracingular surface. 4.not located above the middle third of the lingual

surface except to cover interproximal spaces to the contact points

5. Inferior border-half-pear shape---bulk,rigidity 부여

Linguoplate

Linguoplate All gingival crevices and deep embrasures must be

blocked out parallel to the path of placement to avoid gingival irritation and any wedging effect between teeth

Anterior crowding---The recontouring of lingual proximal surfaces of overlapped ant. Teeth permits a closer adaptation of the linguoplate.

The linguoplate does not in itself serve as an indirect retainer. ---Definite rest is needed for indirect retainer

Both the linguoplate and the cingulum bar should ideally have a terminal rest at each end regardless of the need for indirect retention. These rest may serve as terminal rests for the linguoplate or continuous bar if necessary.

Linguoplate

Terminal rests

Indications for the use of a linguoplate

1. When the lingual frenum is high or the space available for a lingual bar is limited. ---- Less than 8mm

2. In Class I situations in which the residual ridges have undergone excessive vertical resorption.—stability 을 보강

3. For stabilizing periodontally weakened teeth 4. When the future replacement of one or more incisor

teeth will be facilitated by the addition of retention loops to an existing linguoplate

Labial bar Indications May be used when the mandibular teeth are so severely inclined

lingually as to prevent the use of a lingual major connector May be used when large lingual tori exist and their removal is

contraindicated. Labial vestibule depth should be adequate to allow the superior border

to be placed at least 3mm below the free ginginval margins The labial bar tends to lack rigidity since it is considerably longer than

a lingual bar.

Swing-lock design형태 : modification to the

linguoplateLabial bar –hinge/latchMultiple rest linguoplate

Swing-lock design Indication1. Missing key abutments2. Unfavorable tooth contours3. Unfavorable soft tissue contours4. Teeth with questionable prognoses Contraindication1. Poor oral hygiene, lack of motivation for

plaque control by the patient2. Shallow buccal or labial vestibule3. High frenal attachment

Maxillary major connectors Six basic types of maxillary major

connectors 1. Single palatal bar2. Single palatal strap3. U-shaped palatal connector4. Anterior-posterior palatal bar5. Combination anterior and posterior

palatal strap-type connector6. Palatal plate-type connector

A cardinal rule for the location of the major connector in relation to the remaining teeth and to their surrounding gingivae is :

Either support the major connector by definite rests on the teeth contacted, bridging the gingivae with adequate relief, or locate the connector far enough away from the gingivae to avoid any possible restriction of blood supply and entrapment of food debris.

Single palatal bar( 단순구개바 ) 문제점 견고성을 확보하기위해 bulky 한 형태가

되거나 , 보통은 얇게 제작되는 경우가 많다 . 항상 너무 얇게되어 rigidty 가 부족하거나

부피가 커서 환자의 혀에 불편감을 준다 . 매우 좋지 않다 . 그림 5-26 text

Single palatal strap( 단순 구개스트랩 ) Palatal bar 와의 구분은 8mm. Bilateral tooth-supported restorations, even

those with short edentulous spaces, are more effectively connected with a single, broad palatal strap connector, particularly when the edentulous areas are located posteriorly.= Class III

More rigid and less bulky than palatal bar A single bar or strap should not used to connect

anterior replacement with distal extension bases. Sagital section. Midportion of major connector is

slightly elevated to provide rigidity. 그림 5-27 text

U-shaped palatal connector(U- 형 구개연결장치 )

Indication Large inoperable palatal torus Anterior teeth are to be replaced

U-shaped palatal connector(U- 형 구개연결장치 ) Least desirable of Mx. Major connectors 1. Its lack of rigidity (compared with other

designs) can allow lateral flexure under occlusal forces, which may induce torque or direct lateral force to abutment teeth

2.the design fails to provide good support characteristics and may permit impingement of underlying tissues when subjected to occlusal loading

3.Bulk to enhance rigidity results in increased thickness in areas that are a hindrance to the tongue.

U-shaped palatal connector(U- 형 구개연결장치 )

A common error in the design of a U-shaped connector, however, is its proximity to, or actual contact with, gingival tissues.

Gingival irritation and periodontal damage to the tissues adjacent to the remaining teeth.

Combination anterior and posterior palatal bar-type connectors( 전후방 구개바형 연결장치 )

Single palatal bar 와 같은 구조적 결함을 갖는다 .

Bulky 혀에 방해가 된다 .

Combination anterior and posterior palatal strap-type connector( 전후방 구개스트랩형 연결장치 )

Structrally, this is a rigid. It may be used in almost any maxillary

partial denture design It is used most frequently in classes II

and IV.

Combination anterior and posterior palatal strap-type connector( 전후방 구개스트랩형 연결장치 )

A posterior palatal strap 1. Flat, minimum of 8mm

wide2. As posteriorly as possible3. On the hard palate

Longitudinal connectors1. Forming square or

rectangular frame2. Flexure is practically

nonexistent in such a design.

Anterior connector may be extended anteriorly to support anterior tooth replacements.

Palatal plate-type connector( 구개판형 연결장치 )

Any thin, broad, contoured palatal coverage used as a maxillary major connector and covering ½ or more of the hard palate.

Anatomic replica palatal castings have uniform thickness and strength by reason of their corrugated contours

The advantages of the anatomica replica palatal major connector

1. Uniform thin, anatomic contours 열전도성 우수 --- 이물감적고 ,

하방조직에도 적응성 우수2. Corrugation—strength, thin and

adequate rigidity3. Uniform thickness is maintained4. Intimate contact- retention

The palatal plate may be used in any one of three ways

A plate of varing width that covers the area between two or more edentuous areas

Complete or partial cast plate that extends posteriorly to the juntion of the hard and soft palates

In the form of an anterior palatal connector with a provision for extending an acrylic resin denture base posteriorly.

The palatal plate may be used in any one of three ways

Complete or partial cast plate that extends posteriorly to the juntion of the hard and soft palates

In the form of an anterior palatal connector with a provision for extending an acrylic resin denture base posteriorly.( 그림 5-37 text)

Posterior palatal sealPalatal plate should be located

anterior to the posterior palatal seal area.

Little posterior seal is ever necessary with a metal plate. Accuracy and stability.

Indication of the palatal plate

Frequently in Class I situation Canine or first premolar 가 최후방

지대치이고 , residual ridge resorption이 심한 경우 ---complete palatal coverage is strongly recommended.

Design of major connectors

MandibleStep 1. Outline the basal seat areasStep 2. Outline the inferior border

of the major connectorStep 3. Outline the superior border

of the major connectorStep 4. Connect the basal seat area

to the inferior and superior borders of the major connector, and add minor connectors to retain the acrylic resin denture base.

MaxillaStep 1. Outline of primary bearing areasStep 2. Outline of nonbearing areasStep3. Outline of connector areasStep 4. Selection of connector typeStep 5. unification

Beading of the maxillary cast

Purpose1. To transfer the major connector design to the investment

cast2. To provide a visible finishing line for the casting.3. To ensure intimate tissue contact of the major connector

with selected palatal tissues

형성법Cleoid carver 를 사용한다 .0.5mm depth and widthRounded V-shaped grooveAnterior--- valley of rugae

Happy Friday!!!!경청해 주셔서 감사합니다