INTRODUCTION:

From a dentists’ perspective, the word gutta percha immediately makes us think of endodontic obturation. However, going back to history, use of this material can be traced for diverse purposes. Evolution of this material and its current usage in dentistry has come a long way. Ever since its introduction as an obturative material for obliterating the root canal space, gutta percha, in its various forms, has proven to be extremely versatile.

ORIGIN AND OCCURENCE OF GUTTA PERCHA:

Gutta percha is essentially a dried, coagulated sap of a peculiar species of tropical plants. This sap was first obtained from sapotaceae family of trees, which are abundant in the Malay peninsula (south east asia). The name “gutta percha” comes from the plant’s name in Malay- getah perca, meaning “percha sap”.  Most of the plants yielding gutta percha belong to the natural order of sapotaceae, the most important being Dichopsis Gutta or Isonandra Gutta, also known as Palaquium Gutta.3,5

These trees are medium to tall (approx. 30meters) in height, and up to 1meter in trunk diameter. A series of “V” shaped or concentric cuts are made in the trunk to obtain the juice, which is processed by chemical coagulation method or Obach’s technique (flocculation with industrial gasoline and then deresinated) 2, before it is mixed with fillers for dental use.

HISTORY:

History reveals gutta percha being used for a myriad of purposes since the seventeenth century.

• The English natural historian John Tradescant introduced gutta percha to Europe in the mid 1600’s.
• Dr. William Montgomery, a british surgeon, experimented with gutta percha and found out that this new gum was superior to rubber in certain aspects for the use of making surgical instruments.
• James Patterson in 1845 used it to make a hand molded golf ball, which was used extensively till natural rubber was introduced.
• Alexander, Cabriot and Duclos obtained the first patent for gutta percha in 1846, which opened avenues for its use in industry.
• The honor of first constructing telegraph lines insulated with gutta percha belongs to Werner Siemens in 1847. Subsequently underwater cables were also being insulated with gutta percha.
• Edwin Truman in 1847 introduced gutta percha as a temporary filling material in dentistry.
• Hill’s stopping restorative material, a mix of bleached gutta percha and carbonate of lime and silica, was introduced in 1847.
• In 1867, Bowman used gutta percha for the first time to obturate root canals.
• Commercial manufacture of gutta percha points in dentistry was in 1887, by S.S.White
• Standardized gutta percha in dentistry was introduced in 1959.

ROLE OF GUTTA PERCHA IN ENDODONTICS:
Endodontists in the past were constantly in search for an inert, biocompatible material with optimal sealing properties to be used as filling during root canal therapy. Gutta percha was extensively researched upon for usage in endodontics, after which it has been used successfully as root canal obturating material.

CHEMISTRY:

Gutta percha is a trans isomer of polyisoprene. Its chemical structure is 1, 4 trans poly-isoprene. This explains the behavior of gutta percha as a crystalline polymer.2

PHASES OF GUTTA PERCHA:

Two distinct interchangeable crystalline phases exist in chemically pure gutta percha, namely “alpha” and “beta”. Natural gutta percha is in alpha form, whereas commercially available gutta percha is generally in beta form. Apart from the two forms, another amorphous form “gamma” may be seen. Dental gutta percha usually exists in beta semi crystalline phase.

Gutta percha exhibits two crystalline transformations when heated from room temperature to 1000 Centigrade. These transformations can be summarized as follows:

• Beta to alpha: occurs between 420-490C ( this phase transformation is reversible)
• Alpha to amorphous: occurs between 530-590C1

PROPERTIES OF DENTAL GUTTA PERCHA:

• Biocompatibility: highly biocompatible; does not react with body fluids, inert irrespective of alkaline or acidic medium, does not initiate allergic host response.
• Dimensional stability: expansion or shrinkage of material occurs only during phase transformations.
• Ductility and malleability: depending on existing phase, material may be ductile or malleable.
• Melting point: approximate value is around 600C
• Ease of handling: gutta percha used for endodontic obturation purposes are in both alpha and beta forms, both of which are easy to manipulate. When required gutta percha can be easily removed from root canal.
• Adaptation to root apex: apical seal is of prime importance in obturation, which is achieved by using gutta percha, either in cones or warm, thermoplasticized form.

Composition of Gutta Percha:

• Gutta percha used for general purposes typically has composition of:
• gutta: 75-82%
• alban: 14-16%
• fluavil: 4-6%
• also contains tannins, salts and saccharine like substances2.

• • Dental gutta percha composition:
• matrix gutta percha: 20%
• filler zinc oxide: 66%
• radiopacifier heavy metal sulfates: 11%
• plasticizer waxes and/or resins: 3%4

COMMERCIALLY AVAILABLE FORMS OF DENTAL GUTTA PERCHA:

Various methods to obturate the root canal have prompted manufacturers to make gutta percha in different forms. These forms too, have evolved through years. Currently available forms may be listed as:

Solid core gutta percha points:

Available as standardized and non- standardized points ( beta phase).

• Standardized points: these are manufactured in coherence to instrument taper and apical gauge. Increased zinc oxide content adds to stiffness.
• Non standardized points: these are manufactured in variable taper, not necessarily in accordance with a particular instrument. The tip of point is adjusted with an apical gauge to best fit and seal the apex. Flexibility is enhanced due to low content of zinc oxide.

Both standardized and non standardized gutta percha points are used with cold lateral condensation with warm vertical compaction.

Thermoplasticized gutta percha:

Usually available in injectable form (alpha phase).

• Thermoplaticized gutta percha systems provide special heaters which heats the gutta percha till the temperature when it flows. For obturation the apical seal is achieved with the plugging of master cone and then the gutta percha is backfilled.

Since its established use in endodontics gutta percha has been a material of choice for obturating root canals. Achieving three dimensional apical seal is essential for success of root canal treatment. Gutta percha has passed the test of time, to have been able to achieve apical seal. Host acceptance is also an important parameter that determines the success of therapy. Currently researchers are on the look for materials that may replace gutta percha in future. Till then however, gutta percha remains steadfast as a golden standard in obturation.

References:

1. Schilder, H., Goodman, A., Aldrich, W.: The Thermo Mechanical properties of Gutta Percha. III. Determination of phase transition temperatures for Gutta Percha, ORAL SURG. July 1974 Vol 38 No. 1; 109-114.
2. Dr. R. Prakash, Dr.V.Gopikrishna, Dr. D. Kandaswamy; Gutta percha –An Untold story; Endodontology, Vol 17 Issue 2, Dec 2005;32-36.
3. www.wikepidia.com
4. Charles M. Fridman, James L. sandrik, Micheal  A. Heuer and Gustav W. Rapp; Composition and mechanical properties of gutta percha endodontic points; j dent Res September- October 1975 Vol . 54, No. 5; 921-925.
5. Gutta Percha