Access to cervical limits
- Definition of access to cervical limits:
The term most often used to describe this clinical phase is gingival retraction; this term does not seem appropriate to us because it implies a notion of per and post-operative removal of the marginal gingiva which is in complete contradiction with the desired goal.
In fact, a single qualifier cannot encompass all the techniques for accessing cervical limits, which can be classified into two groups.
- Interest in accessing cervical limits :
The aim of this clinical sequence is to:
-Allow visual access to the limits by the operator.
-Allow access of the impression material to the LC to record with sufficient thickness:
- full limit (best quality of JDP)
- a portion of the unprepared tooth surface (better emergence profile)
3. Factors involved in choosing the type of access to the limits:
- Number and location of teeth affected.
- Anatomy of the affected teeth.
- General condition.
- Location of the limit.
- Sulcus depth and its anatomy.
- Texture and thickness of the free gingiva (Periodontal typology).
- Impression technique and materials used.
4. The required characteristics of access to the limits:
- Easy
- Painless
- Fast acting
- Allow sulcular opening for sufficient time
- No secondary action on a local level (irreversible recession, periodontal pocket, etc.)
- No secondary action on a general level (allergy, etc.)
5. Techniques for accessing cervical limits:
5.1. Deflection access techniques:
Deflection characterizes the progressive movement by which a body abandons the line it describes to follow another.
5.1.1. Deflection by physical processes:
- Deflection by the dike
- the impression only concerns a limited number of preparations and on a single sector of the arch and when the LCs are very little subgingival.
- Must be used with a modified impression tray (case where the clamp prevents its placement)
- Should not be used with polyvinyl siloxane impression materials as the rubber inhibits their polymerization.
Access to cervical limits
- deflection mediated by transitional prosthesis
This technique requires an additional session for taking the impression; it consists of slightly oversizing the cervical area of the transitional prostheses to cause a horizontal deflection of the free gingiva allowing a good recording.
Indicated especially in cases of tormented anatomical shape.
Positive points
- Major interest cases of complex anatomical profiles in the cervical area
- Simultaneous achievement of the objectives of transitional prosthesis and access to limits.
• Multiple preparations.
Negative points
- Lack of control.
- Inconsistent results.
- Additional clinical session.
- deflection by dry cords:
This method consists of placing one or two cords in the sulcus which will mechanically separate the free gum and open the sulcular space.
-This space will remain open for a few minutes after removal of the cord thanks to the viscoelasticity of the gum and thus allows the penetration of the impression material.
– Indication : Healthy periodontium
Access to cervical limits
Impact on the periodontium
-A moderate recession of 0.1mm is expected after any gingival retraction.
-Gingival injury caused by dry or soaked cord heals within 6 to 10 days when not left for +15 minutes 1 .
– Unimpregnated cords placed in the sulcus are safe if they are not left for more than 30 minutes.
The risk of permanent gum recession is greater when:
- A cord is left in a thin gingival sulcus for more than 15 minutes.
02 cords are inserted one on top of the other without pressure control in a shallow sulcus.
- a- Simple cord technique:
Consists of placing a single cord of large diameter compatible with the depth of the sulcus after probing it (thin, rounded spatula)
- Indication
Healthy gum tissue
Positive points
Quick and easy gesture if the periodontium is thick and fibrous
Negative points
- Difficulty of insertion in case of thin gum/shallow sulcus.
- Risk of damage to the attachment
- Risk of bleeding during removal
- Used on a limited number of teeth.
- b- Deflection by double cord
To address the above problems, many authors prefer the use of the double cord deflection technique.
Positive points
•atraumatic.
- Usable in many clinical situations.
- Protective role of the epithelial attachment.
- Inexpensive instrumentation.
Negative points
- Requires minimal sulcular depth.
- Difficult to use with Stein’s preparation technique.
- Long method in the case of multiple preparations.
- Anesthesia sometimes necessary.
- CI with tormented anatomical forms.
The effectiveness of dry cords remains partial because cords alone do not effectively control possible bleeding, hence the interest in combining chemical substances. On the other hand, their deflection power remains low compared to that of impregnated cords.
- 5.1.2. Deflection by physicochemical process (soaked cord)
Consists of placing in the sulcus a cord impregnated with an astringent (aluminum chloride, etc.), hemostatic (ferric sulfate), vasoconstrictor (adrenaline) or caustic (sulfuric acid) chemical solution in order to:
- control the bleeding
- limit the time of application of the cord
It is found in the trade
-pre-impregnated and dried cords.
– dry cords.
– impregnation solutions in bottles.
The products used are:
- 8% racemic adrenaline (CI: hypertension, diabetes, hyperthyroidism, allergy to adrenaline, under reserpine ganglion inhibitor, monoamino oxidase
“depression”)
- Buffered aluminum chloride (Hemodent 14%)
- potassium sulfate
- ferric sulfate
- epinephrine
These substances are used with caution, particularly on thin, slightly fibrous gums. Their harmfulness can result in irreversible gingival retraction, which depends on:
– the nature of the substances and their association;
– their concentration;
– application time.
- 5.1.3. Deflection by chemical process “the Expasyl system”:
The Expasyl concept involves the use of a paste based on kaolin containing aluminium chloride.
-Introducing the paste into the sulcus produces a double action:
- It pushes back the marginal gum thanks to its dense texture.
- It exerts an astringent and haemostatic action due to the presence of aluminium chloride.
Positive points
- No periodontal aggression.
- Without anesthesia.
- Fast.
- Hemostatic effect.
- Possibility of association with other techniques.
- Multiple additional indications.
- No systemic effect.
Negative points
-Risk of injection into a site that does not allow rinsing (pocket).
-Specific materials and equipment.
-Less effective on thick periodontium
-Risk of recession if application time is greater than 2 or 3 minutes on thin periodontium.
Access to cervical limits
Access to cervical limits
- 5.2. Tissue eviction access technique:
They consist of eliminating the first epithelial cell layers on the internal slope of the free gingiva; this elimination, when well conducted, provides the necessary and sufficient space for the impression material.
- 5.2.1. Electrosurgery:
Electrosurgery involves the use of high- frequency currents that are rectified and filtered through a thin electrode.
Thus the cells in contact with this electrode will be volatilized.
Positive points:
- In the case of LC near the epithelial attachment.
- Quick method.
- Little or no bleeding.
- ideal for multiple preparations.
- Compatible with all types of imprint.
- suitable for tormented cervical anatomies.
- in addition to deflection on:
-thick periodontium (insufficiently separated by wire)
Negative points:
- Formal contraindication in pacemaker wearers.
- Mastery of gestures required.
- Risk of gingival retraction in certain clinical situations.
- Anesthesia required.
- Specific material.
- Rotary curettage:
First described by AMSTERDAM 1954, taken up by HANSING and developed by INGRAHAM
Rotary curettage performs a double operation:
- The removal of a thin layer of the inner epithelium of the free gingiva. Simultaneously, the preparation of the supporting tooth.
Positive points:
- Simultaneously completes the end of the preparation and access to the limits
- Quick technique
- Suitable for multiple preparations
- Rapid healing without reactive retraction.
Negative points:
- Visibility problem to complete the preparation, the sulcus not being open
- The surgical procedure must be perfectly controlled.
- Risk of bleeding.
- Anesthesia often required.
5.2.3 Combination of techniques
Electrosurgery + Rotary curettage + chemical deflection “Expasyl”
Access to cervical limits
Deep cavities may require root canal treatment.
Interdental brushes effectively clean between teeth.
Misaligned teeth can cause chewing problems.
Untreated dental infections can spread to other parts of the body.
Whitening trays are used for gradual results.
Cracked teeth can be repaired with composite resins.
Proper hydration helps maintain a healthy mouth.