Fluffy buds with a wide variety of shades and a charming aroma - all this...
The sandwich technique is considered as an alternative to the adhesive technique. It is based on the application of a two-layer filling (from the English sandwich). In this case, dentin is restored with glass ionomer cement, and enamel is restored with a composite.
In a broader sense, the sandwich technique is understood as a combination of two permanent filling materials:
– glass ionomer cement/composite;
– compomer/composite;
– hybrid composite/microfilled composite.
The sandwich technique can be used in most cases of filling with composites, but it is especially indicated for filling defects in the neck or root of a tooth, large volumes of carious cavities, and restoration of pulpless teeth.
This method is preferred for non-carious lesions of hard dental tissues, when the enamel and dentin are pathologically altered and adhesive systems designed for the normal structure of tooth tissues do not provide sufficiently strong adhesion of the filling.
The sandwich technique is also indicated in cases where it is impossible to achieve complete drying of the carious cavity.
Stages of filling using the sandwich technique:
1. Cleaning teeth from plaque
2. Selection of the shade of filling material
3. Preparation of a carious cavity
4. Isolation of the tooth from saliva
5. Medicinal treatment and drying of the carious cavity
6. Applying a gasket
Despite the high biocompatibility of glass ionomer cements, the deepest areas of the cavity should be covered with a therapeutic lining based on calcium hydroxide. After this, the dentin is restored with glass ionomer cement so that the thickness of the composite layer on the chewing surface is at least two millimeters.
There are 2 options for applying a GIC gasket (Fig.95):
A) “Closed” sandwich - the lining does not reach the edges of the cavity and, after applying the composite, does not come into contact with the oral environment.
B) “Open” sandwich - the gasket covers any wall of the cavity, contacting the oral environment. This technique is most often used for filling class 2 cavities, especially when the cavity is located subgingivally and it is impossible to completely dry it due to the penetration of gingival fluid into the cavity. In this case, the contact point must be restored with a composite.
Rice. 95. Application of a gasket using the sandwich technique for filling carious cavities: a – “closed” sandwich; b – “open” sandwich
7. Etching
After the GIC has cured, an etching agent is applied to the surface of the enamel and gasket.
The etching time is no more than 30 seconds. The cavity is then washed with water and dried with air. Not only the surface of the enamel becomes micro-rough, but also the surface of the glass ionomer gasket. Next, filling is carried out according to the usual method of using composites.
8. Application and polymerization of enamel bonding agent
The adhesive is applied with a brush to the etched enamel, the surface of the glass ionomer gasket and is evenly distributed throughout the cavity.
If GIC covers the entire dentin surface, the use of a dentin adhesive is not necessary.
Polymerization occurs depending on the polymerization method (chemical or photocurable).
9. Introduction into the cavity and curing of the composite material
10. Final processing of the filling
11. “Rebonding” (“postbonding”)
12. Fluorization of the tooth being restored
When using “classical” and water-curing GIC, filling using the sandwich technique should be carried out in 2 visits. On the first visit, the entire cavity is filled with GIC. On the 2nd visit, part of the glass ionomer filling corresponding to the enamel is removed, then etched and filled with a composite. If this rule is not observed, the composite, which quickly forms a strong bond with the glass ionomer gasket, “tears off” the “immature” GIC from the bottom of the cavity due to polymerization shrinkage. This leads to the creation of negative pressure under the filling, “retraction” of odontoblast bodies into the dentinal tubules, damage and death of these cells, postoperative sensitivity, microbial invasion into the pulp and the development of inflammatory complications (pulpitis, periodontitis).
The use of hybrid double- and triple-curing GIC allows filling a carious cavity using the sandwich technique in one visit.
Positive aspects of the sandwich technique:
1). The GIC layer plays the role of a shock-absorbing cushion under the relatively
brittle composite, thereby increasing the strength of the filling.
2). The use of GIC as a base gasket solves the problem
adhesion of filling to dentin – between cement and hard tissues
a chemical bond is formed, and with the GIC composite it forms a strong
micromechanical connection.
3). Fluoride release from glass ionomer promotes compaction
hard dental tissues, reduces the risk of secondary caries.
4). Coating GIC with a layer of composite eliminates this
disadvantage of glass ionomer cement, such as low abrasion resistance.
5).The application of a thick (base) gasket made of GIC allows you to reduce
volume of introduced composite material, which reduces
polymerization shrinkage of the filling, reduces internal stress and the possibility of deformation of the filling, reduces the consumption of expensive composite material.
6). The use of a GIC gasket improves aesthetics
applied filling due to the natural opacity of glass ionomer (well imitates dentin).
7). In a number of clinical situations, the use of the sandwich technique is more
preferable to the adhesive technique, for example, when restoring defects in the neck and root of a tooth in the absence of enamel.
"Sandwich technique" is often used in modern
restorative dentistry and consists of
using cements in combination with
composite materials for restoration
a tooth destroyed by caries and
replacement of tooth dentin. Layer-by-layer application
the above materials resembles a sandwich
(English - sandwich).
■ In patients with poor hygiene.
■ In patients with increased caries susceptibility.
■ When restoring large carious cavities.
■ When restoring cavities in pulpless teeth in combination with
composite material.
■ When filling defects in non-carious lesions of hard tissues in
combination with composites.
■ When filling defects in the cervical area and in the area of the tooth root in
combinations with composite materials.
■ With a “combined” tunnel (approximal-masticatory cavity of class I-II, with
preserved marginal ridge).
■ When restoring a class II cavity prepared according to the technique
"vertical tunnel".
■ When filling, when it is impossible to achieve absolute dryness
carious cavity. Closed sandwich
GIC or compomer fills the cavity to the enamel-dentin border,
The top is covered with a composite material. Closed
“sandwich technique” is used in cavities of classes I, II, III, IV, V according to
Black. Open sandwich
The method is to use glass ionomer cement in
areas in contact with the gum, without overlap in this area
composite material. The open sandwich technique can
used for filling cavities of classes II, III, V according to
Black. With the “sandwich technique”:
In cavities of class I according to Black, the GIC should
cover the bottom of the carious cavity and
reach the enamel-dentin border. In cavities of class II according to Black, it is necessary to form
gingival wall of approximal cavities
so that the GIC does not reach the contact point.
The composite material must be completely
cover the GIC on the chewing surface and
partially/completely on the proximal one. ■ In cavities of class V according to Black in the presence of carious
cavity located under the gum, the GIC should
line the bottom of the carious cavity and restore
defect up to the gingival margin (gingival margin 2 mm).
■ In combined cavities - GIC or compomer
borders.
■ In the vertical tunnel technique - material
fills the tunnel and cavity to the enamel-dentine
borders. Material requirements
GICs and compomers used in sandwich technology must
have:
- compressive strength to withstand occlusal
load;
- tensile strength (resistance to compositional
shrinkage);
- sufficient working time, but fast curing;
- low sensitivity to moisture;
- radiopacity;
- chemical and mechanical adhesion to the composite;
- elasticity;
- good aesthetics (sufficient number of colors). Methodology for using hybrid GIC
Vitremer (ZM ESPE) in the “sandwich technique”: 1. The tooth is cleaned with paste. The color of the tooth and the future are determined
restoration. The cavity is prepared with maximum
preservation of enamel and dentin. The color of dentin is determined
according to the available color. For insulation from moisture
rubber dam and cotton rollers are used. If it is needed,
the matrix is installed.
2. Dentin is dried with an indirect stream of air or excess
moisture is removed with a foam ball or applicator.
Dentin should remain moist (shiny).
3. Rubbing in the primer for 30 s, drying,
light polymerization - 20 s.
4. Preparation of material. The bottle of powder is shaken
before kneading. Depending on cavity size
an equal number of spoons of powder and drops are used
liquids. The orange capsule is filled with material.
5. GIC is introduced into the prepared cavity. 6. To condense the material in the cavity, use a wrung out
cotton ball moistened with distilled water. Not
recommended for compacting material
alcohol, mixing liquid, primer.
7. Traditional GIC chemical curing accepted
use as follows in the sandwich technique:
- 1 visit: filling of the entire cavity with GIC;
- 2nd visit: removal of the top layer of GIC (2-3 mm thick) and
covering with composite material.
8. When used in the “sandwich technique” Vitremer" and restoration
cavities can be completed in 1 visit. 9. After self-curing (4-6 min) or light polymerization
material, it is necessary to remove excess cement from the tooth enamel.
10. The cavity is washed and dried, on enamel and GIC for 15 s
The etching gel is applied and washed off for 20-25 s.
11. An adhesive system (for example, Adper Single Bond) is applied to
dried GIC and enamel surfaces. After applying the second
The bond layer is dried for 5 s and polymerized with light 10
With.
12. Addition of composite material.
13. Stages of final processing of the restoration (polishing,
grinding).
O. E. Khidirbegishvili,
G. B. Makhviladze
Georgia, Tbilisi
In the early 1970s, Alan Wilson developed a new glass ionomer cement (GIC) based on the well-known silicate cement. The first GICs were difficult to work with and were very sensitive to water absorption and dehydration. The material received true recognition only in 1984, when it began to be supplied to the market in capsules (Ketac Aplicap system, ESPE). It took some time before this material was combined with a more durable composite. Using the so-called “sandwich method”, such negative qualities of the composite as compression, leakage and secondary caries were eliminated. This method was first described by W. McLean in 1977.
However, the traditional sandwich method had many disadvantages. The total duration of such restoration significantly exceeded the time spent on amalgam restoration. The complete curing time of GIC (24 hours) is one of the main reasons why clinicians have abandoned the use of this method. Another significant drawback was the etching of incompletely cured GIC. Intensive drying led to the destruction of cement. In addition, the binders were water-repellent (hydrophobic), which did not allow for a strong bond. Most often, problems arose at contact points and related to occlusal wear of the composite and dissolution of GIC at the junction with the composite. The latter was due to prolonged etching, washing and especially drying of the GIC before applying the composite. Therefore, the sandwich method had to be modified.
After cavity preparation, the dentin was first cleaned and the enamel etched, and then GIC was applied. The cement etching procedure could be skipped, but the binder could be immediately applied to the GIC and etched enamel. Then, without waiting for the cement to harden, the composite was placed immediately after applying the bonding agent. The advantage of this modified sandwich method is that it saves time and that the cement that has not completely hardened can compensate for the polymerization shrinkage of the composite. However, the greatest advantage is that the still soft GIC is not washed and dried, which provides the best conditions for its hardening and the disappearance of cement at the composite-GIC interface.
The modified sandwich method is a clear advance, providing higher quality restorations and saving time. However, this method also has significant drawbacks. First of all, this is due to the fact that the GIC layer is located under the composite and has no connection with the environment, (closed sandwich). As is known, GICs have an anti-caries and mineralizing effect due to the rather extensive flow of fluoride ions that occurs for a long time. However, the GIC located under the composite will not fully demonstrate its preventive properties associated with the release of fluoride, since this requires replenishment of fluoride ions when using fluorine-containing drugs. In addition, the absorption of water by GIC leads to swelling, which compensates for the compression of the material. The fulfillment of these important conditions, in fact, was prevented by the composite layer, which completely covered the GIC.
Later a method was proposed open sandwich– GIC covers any wall of the carious cavity, coming into contact with the environment of the oral cavity after applying the composite to it. The open sandwich method is more reliable. But, unfortunately, this method also has disadvantages. In case of poor oral hygiene (i.e. low pH), some of the GIC may disappear within a few years due to its dissolution. This is especially facilitated by the proximity of the gingival papilla and difficult access to proximal surfaces for complete hygienic cleaning.
These cements contain from 12% to 18% water. In clinical settings, water may be absorbed from dentin or saliva. The absorption of water leads to swelling, which can compensate for the compression of the material. During curing, when GICs cannot absorb water, they shrink by 3-4%. The coefficient of thermal expansion of GIC approximately coincides with the coefficient of expansion of enamel and dentin, therefore these cements have a good thermal insulation value. In terms of bending strength and wear resistance, GICs are inferior to composites. Despite the fact that GICs have high biocompatibility, they still have certain disadvantages, such as the degree of acidity (pH), the emission of small amounts of aluminum, the duration of maturation of the filling (24 hours), surface roughness, color change, etc.
One of the most important advantages of GIC is that they release fluoride compounds over a long period of time. In addition to fluorides, other minerals are released, such as silicates and calcium ions, which also participate in the mineralization process. After maturation, glass ionomer cements can reabsorb fluoride and then slowly release it. This can happen, for example, when consuming fluoride toothpastes or lozenges. Thus, GICs act as a fluoride reservoir. It is this factor that can explain their bacteriostatic and mineralizing effect, which results in no relapses of caries. It should be noted that GIC can enter into a chemical bond with hard dental tissues due to the formation of ionic and covalent bonds between the carboxylate groups of polyacrylic acid with hydroxyapatite. The connection between dentin and collagen has not yet been proven. The positive properties of GIC, such as good marginal fit and minimal shrinkage, also deserve attention.
GIC consists of two components - powder and liquid. The powder consists of calcium-aluminum-silicate glass with the inclusion of droplets saturated with calcium fluoride. The liquid consists of distilled water or one of the varieties of polycarboxylic acid, which contains about 5% tartaric acid. After mixing the powder and liquid in the first stage, a carboxylate gel is formed, which is sensitive to moisture and drying. In the case of initial moisture penetration, the binding time increases and the strength and hardness of the GIC decreases. Therefore, protection by means of varnishes or matrices is necessary. If you overdry the GIC at this stage, it becomes dull and opaque, cracks and does not fully bind. However, after a few hours, when aluminum ions penetrate into the matrix, forming a water-soluble calcium-aluminum-carboxylate gel, further penetration of water contributes to the final stabilization of the cement. All these factors must be taken into account by the clinician when working with GIC.
Attempts have been made to increase the strength and wear resistance of the material by adding metals such as silver and amalgam. However, this led to the opposite effect. The only advantage of such GICs is their high susceptibility to X-rays. Other developments include plastic-reinforced GICs (plastic-modified GICs) and “compomers.” The exact name of the last group is “polyacid-modified plastics.” The name indicates that, in essence, these are composite materials to which they tried to impart the properties of GIC. However, these new materials did not live up to our hopes. None of these materials could directly bond with the tooth structure, meaning that a bonding system was needed. In addition, compomers only cure when exposed to light. The reaction mechanism is similar to that for composites: there is practically no acid-base reaction. Based on this, compomers are stronger than GIC, but weaker than composites. It is questionable whether this level of fluoride release is sufficient to provide protection to dental tissues, since the magnitude of fluoride emission and absorption are determined by the acid-base reaction. It should be noted that light-curing GICs are more convenient to use, but have unpleasant side effects. Due to water absorption, these materials expand significantly (up to 5%), and polymerization shrinkage is 7%. In addition, light-curing GICs have insufficient depth of solidification of layers with a thickness of more than 2 mm.
Recently, plastic-modified GICs have appeared. These materials are chemically cured and do not require exposure to light. The advantage of this combination is that the glass ionomer component (acid-base), unlike the light-curing version, acquires the property of curing properly. The positive qualities of such cements include high strength, low solubility and very high bond strength. This material is especially suitable for securing dentures with very weak retention. The disadvantage of this cement is the presence of HEMA material in its composition. Hence, there is a very high probability of swelling as a result of water absorption. Based on the foregoing, we can conclude that not all innovations are an achievement and that GIC reinforced with plastic acquires more and more properties of composites, and composites acquire more and more properties of GIC.
After 20 years of use, glass ionomer has gained widespread acceptance as a filling material. Despite the fact that during this time we have not been able to completely eliminate its shortcomings and obtain a perfect filling material, GIC can rightly be considered one of the first “biomimetic” filling materials in the history of dentistry. It owes this, first of all, to such phenomenal properties as fluoride release, remineralization, bacteriostatic effect and a complete chemical connection with dental tissues. No modern filling material can “boast” of these qualities. However, it is necessary to find new ways to overcome the significant shortcomings of this material and more rationally use its unique capabilities. Therefore, I want to offer my developments of sandwich technology, which differ from those previously proposed.
First of all, it seems to me that the opinion of the authors who consider the sandwich technique to be one of the options for basic linings is incorrect. The sandwich technique usually means a combination of two permanent filling materials. It is well known that special gaskets are used for gaskets, and restorative GICs are used for sandwich technology for the restoration of tooth crowns.
In this case, should we call the base lining a permanent filling material that fills the cavity to the enamel-dentin border, and its amount is greater than or equal to the amount of the composite? It is important to note that the sandwich technique is not used to protect tooth tissue from the toxic effects of the composite (separation function), but, on the contrary, as a means of binding the composite to the tooth tissue. The sandwich technique can be considered as an alternative to the adhesive technique for non-carious lesions of hard tooth tissues, when the enamel and dentin are pathologically changed, and adhesive systems designed for the normal structure of tooth tissues do not provide sufficiently strong adhesion of the filling, and, therefore, the GIC layer located under composite filling cannot be considered a gasket. Therefore, in this case, a more correct definition would be a glass ionomer filling coated with a composite.
The main purpose of using GIC in the sandwich technique is its preventive effect, mineralizing and bacteriostatic effect, reliable chemical bond with dentin, especially in restorations experiencing increased occlusal load. The main purpose of using a composite in sandwich technology is to prevent such disadvantages of GIC as low strength, wear resistance and color change. The sandwich technique will remain necessary until clinicians have a perfect filling material in their arsenal. Today we are forced to combine GIC and composite, which successfully complement each other.
The main achievement of sandwich technology is the method open And closed sandwich. The disadvantages of both of these methods were noted at the beginning of the article. To somehow compensate for these shortcomings, I would like to propose a method half-open sandwich(Fig. 1). The essence of the method is that the GIC communicates with the oral cavity using a small hole made in the center of the composite. Through this hole, both the release of fluoride ions and its subsequent accumulation occur when using fluoride-containing pastes and lozenges, which makes it possible to rationally use the preventive properties of GIC. The main occlusal load is borne by the composite, and the abrasion of the GIC in this case is minimal. It must be taken into account that the chewing surface of the tooth is the most accessible and cleanable from a hygienic point of view, which to some extent prevents the dissolution of GIC.
However, situations arise in the clinic when a different approach is necessary. For example, if, as a result of the preparation of carious lesions located on the chewing and vestibular surfaces of a molar, the prepared cavities communicate with each other, in this situation the chewing surface to the enamel-dentin junction is covered with a composite, and the remaining cavity is filled with GIC, which communicates with the environment of the oral cavity. In this case we can talk about combined sandwich method.
Fig.1. Various sandwich technology options
Sandwich technology can be used:
- With extensive loss of dental tissue with preserved enamel edge.
- For large cavities extending into the root cementum.
- When replacing amalgam fillings with insufficient cavity retention configuration.
- When filling non-carious defects and cavities with pronounced mineralization.
This technique is especially necessary when the arch of the pulp chamber (dentinal bridge) is a thin and elastic septum, sometimes with signs of demineralization. In this case, as a rule, manifestations of focal inflammation are observed in the pulp, and the consequences of polymerization shrinkage of the filling material in such a situation are especially destructive for it.
In this situation, it is difficult to guarantee process stabilization, because The use of calcium hydroxide as a gasket is questionable. It has been scientifically proven that calcium hydroxide is a strong base and its use can lead to pulp necrosis, and there are no other therapeutic linings that could cause reliable mineralization of tooth tissue. Therefore, if the clinician seeks to avoid tooth depulpation, the sandwich method should be performed. I would like to propose a technique that is somewhat different from those discussed above and it is advisable to call it late sandwich. In the first stages of this method, if possible, we remove the disintegrated tissue and cover the entire cavity with GIC for six months. If the process progresses favorably, tooth tissue undergoes mineralization due to the release of GIC fluoride compounds. Diffusion of fluoride in tooth tissue causes not only their mineralization, but also reduces the permeability of dentin, stops or slows down residual caries, and also worsens the living conditions of microorganisms.
Unlike the method closed sandwich, the absence of a composite layer promotes the absorption of water by the GIC, which leads to swelling, which compensates for the compression of the material. This is very important, since polymerization shrinkage of the material can negatively affect the condition of the dental pulp. It should also be noted that some GICs, such as 3M TM ESPE TM Ketac MoLar are capable of not only releasing fluoride ions, but also absorbing them from toothpastes, chewing gums, etc. followed by their release during the period of decreasing salivary pH.
After this period, if the process is favorable, we partially remove the GIC layer and cover the remaining cavity with a more durable composite. In this case, the method late sandwich can be considered both preventive and diagnostic, allowing to determine the possibility of preserving the dental pulp.
The industry, based on the latest advances in science, will constantly offer more and more new dental materials, and only a few years after their use it will become clear how satisfactory they are. Traditional glass ionomer cements have not yet said their last word. Perhaps, in the near future, universal glass ionomer cements or composites will appear, as a result of which there will be no need to use the sandwich technique.
The material is taken from the author’s monograph “Modern Cariesology”.
Direct restorations using the sandwich technique of the posterior group of teeth are an aesthetically effective and cost-effective method for restoring hard tissue defects. But in the vast majority of cases, composite materials are used.
L. A. Lobovkina
Ph.D., doctor of the highest category, head of the treatment and prophylactic department of Branch No. 6 of the Federal State Institution “GVKG im. Burdenko" of the Ministry of Defense of the Russian Federation
A. M. Romanov
Candidate of Medical Sciences, Chief Physician of the Implamed Clinic (Moscow)
Composites pros and cons
Currently, in most cases, composite materials are used for direct dental restoration. In cases with large restorations, the adhesion of the composite to the tooth enamel helps to re-strengthen its structure, unlike metal restorations, which do not have the same benefits. However, along with the advantages, they have a number of disadvantages: polymerization shrinkage and deformation of large-volume fillings over time, insufficient biocompatibility with hard dental tissues, lack of cariesstatic effect, high cost. In addition, taking into account the peculiarities of the anatomical structure of dentin and its insufficient mineralization, composites are not recommended for use in children and adolescents (under 14 years of age).
Will GIC replace it?
Considering the above, more attention should be paid to glass ionomer cements (GIC), which have physical and chemical affinity for hard dental tissues. Due to its diffusion-based adhesion to both healthy and partially demineralized dentin, glass ionomer cement is an ideal cavity sealing material, preventing access of bacterial nutrients and reducing any colonies remaining in the cavity to a latent state. It has also been proven that fluoride and other apatite-forming ions can penetrate carious dentin to a significant depth, thereby remineralizing it.
Considering the peculiarities of the anatomical structure of dentin and its insufficient mineralization, composites are not recommended for use in children and adolescents (under 14 years of age).
How to restore a large cavity?
In the practice of a dentist, significant difficulties often arise when restoring teeth with large carious cavities extending under the gum, as well as when restoring hard tissues due to defects in the neck or root of the tooth. Since composites are hydrophobic materials (i.e. they are afraid of the presence of moisture), it is impossible to achieve their good adhesion to the hard tissues of the tooth in the above cases.
Therefore, in some cases it is more expedient to use the sandwich technique, which consists in using GIC in combination with composite materials. In addition, in patients with a “problematic” oral cavity (those with a low level of hygiene, a high level of CP and a high incidence of “recurrent” caries), they can be used independently.
Disadvantages of GIC
It is advisable to note that, along with the positive characteristics of GIC, they have a significant drawback - high opacity, which does not allow obtaining highly aesthetic restorations when using only these materials.
In this regard, companies producing dental materials are looking for ways to improve GICs, including increasing their aesthetics.
The rationality of sandwich technology
In some cases, it is more expedient to use the sandwich technique, which consists in using GIC in combination with composite materials.
The use of such translucent reactive glass provides the material with better aesthetics compared to its analogues by reducing opacity and increasing transparency. Therefore, given the very similar physical and handling characteristics of modern condensed glass ionomers, the choice of material for restoration should be made taking into account its aesthetics.
In addition, another advantage of Ionofil Molyar is the convenience of its application and ease of adaptation to the bottom and walls of the cavity. It also has a low cost. Thus, one restoration (depending on the size of the cavity to be filled) costs an average of 20-40 rubles in material, which makes this cement quite affordable even for budgetary medical institutions.
It has also been proven that fluoride and other apatite-forming ions can penetrate carious dentin to a significant depth, thereby remineralizing it.
Sandwich technique on a chewing tooth [Clinical Example]
Patient T., 24 years old, came to the dental clinic with complaints of short-term pain from temperature stimuli in the area of the 4.7 tooth (Fig. 1). An objective examination of tooth 4.7 revealed a restoration that did not meet clinical requirements. Considering that the patient had a low level of caries resistance of hard dental tissues, as well as a significant cavity volume, the sandwich technique was chosen for treatment.
Rice. 1. Tooth 4.7: initial clinical situation.
Conduction anesthesia with UbistesiniForte 1.5 ml was performed, the tooth surfaces were cleaned of pellicles with Clint paste (VOCO), and the color of the future restoration was determined. A rubber dam was applied, the failed restoration was removed, and a cavity was formed. After medicinal treatment of the cavity with a 2% chlorhexidine solution, a basic gasket from the Ionofil Molar GIC was applied (Fig. 2).
Rice. 2. A gasket made of GIC “Ionofil Molyar” was applied.
Next, adhesive preparation of the cavity was carried out and its restoration was carried out using the nanohybrid composite “Grandio” (VOCO), which has reduced polymerization shrinkage, improved physical and mechanical characteristics and the highest color stability. Then the rubber dam was removed and the restoration was finished (Fig. 3).
Rice. 3. Tooth 4.7: final appearance after restoration.
Double-curing glass ionomer cement “Ionolux” (VOCO, Germany), which appeared relatively recently on the dental market, has already won the love of many dentists. Ionolux combines glass ionomer and composite parts, which determine its excellent properties.
Thus, due to the composite component, its aesthetic qualities have improved, the possibility of immediate finishing has become possible immediately after polymerization, the formation of a chemical bond with composites and very low solubility in water have been noted.
Unlike analogues, when working with Ionolux, there is no need for adhesive preparation of hard dental tissues (for example, there is no stage of priming of hard tissues), since it is a self-adhesive cement. It is well known that the more curing mechanisms a GIC has, the less fluoride ions it releases into surrounding tissues. However, in terms of the release of fluorine ions, Ionolux is not inferior to classical GIC.
Example of sandwich technique in the first molar [Clinical Example]
Patient L., 23 years old, came to the dental clinic with complaints of spontaneous pain at night, aggravated by the action of temperature stimuli in the area of the 3.6 tooth. An objective examination of tooth 3.6 revealed a carious cavity filled with food debris and softened dentin. On probing there is sharp pain at one point. First, endodontic treatment was performed (Fig. 4).
Rice. 4. Tooth 3.6 after endodontic treatment.
Considering the presence of a large cavity in the patient, the sandwich technique was chosen for treatment (Fig. 5). Next, adhesive preparation of the cavity and its restoration with the Grandio nanohybrid composite were carried out. After removing the rubber dam, macro- and microcontouring of the restoration was performed.
Rice. 5. A gasket made of GIC “Ionolux” was applied.
For this purpose, peak-shaped and flame-shaped diamond burs of low and ultra-low abrasiveness (SSWhite) were used, as well as Dimanto universal polishing heads (VOCO) with an air-water spray without polishing paste (Fig. 6). The final appearance of the restoration of tooth 3.6 is shown in Figure 7.
Rice. 6. Tooth 3.6: polishing stage using a Dimanto polishing head.
Rice. 7. Tooth 3.6: final appearance after restoration.
Using the JIC [Conclusions]
Along with the positive characteristics of GIC, they have a significant drawback - the high opacity of the material, which affects the final result of the restoration.
Thus, restoration of defects in the area of the lateral group of teeth using a composite is a very popular method of treating caries. However, we should not forget that in a number of clinical situations the sandwich technique is more preferable. In addition, the sandwich technique used in these clinical cases provides not only a therapeutic effect, but also reduces the cost of restoration due to less use of more expensive composite material, which is especially important during the economic crisis.
Sandwich Technique: A Cheaper and Faster Method for Restoring Chewing Teeth During the Economic Crisis updated: December 30, 2016 by: Alexey Vasilevsky
Bonding technique a method of technology that made it possible to achieve micromechanical adhesion of the composite to tooth tissues, or more precisely, only to its enamel.
It is used for filling with composites that have hydrophobic adhesive systems that provide bond only to tooth enamel. These are chemical-curing composites and some “cheap” light-curing composites. Due to its low efficiency, the bonding technique should be used limitedly, in the presence of good conditions for fixing the filling, as well as for material reasons - in the absence of the doctor being able to use an expensive composite with an effective dentin adhesive and lining glass-ionomer cement. A prerequisite for carrying out the bonding technique is contact of the filling with the tooth enamel along the entire perimeter of the cavity, i.e. This technique is ineffective for abrasion of enamel on the chewing surface, for filling cervical and subgingival cavities, and root caries.
Many stages of filling teeth using the bonding technique are performed according to the same rules as with the adhesive restoration technique, therefore, in order to avoid repetition, we will dwell in detail only on those stages whose implementation has any differences and features.
Stages of applying a composite filling using bonding technology.
1. Cleaning teeth from plaque.
2. Planning the construction of the restoration and selecting the shade of the filling material.
3. Preparation of a carious cavity.
4. Isolation of the tooth from saliva.
Considering the fact that only hydrophobic materials are used in the bonding technique, the isolation of the tooth and carious cavity from saliva must be especially careful.
5. Medicinal treatment and drying of the carious cavity.
6. Applying an insulating pad.
When using bonding technology, i.e. when using a hydrophobic binder aieirra, which does not have adhesion to dentin, a liper spacer made of zinc phosphate, polycarboxylate cement or insulating varnish is applied to the bottom and walls of the carious cavity strictly to the enamel-dentin border (see Fig. 290). The entire dentin surface must be covered with an insulating spacer. If dentin is not isolated in any area, then due to the fact that the hydrophobic bonding agent does not bind to it and does not seal its surface, conditions are created for microbial invasion into the pulp and the development of inflammatory complications - pulpitis or periodontitis.
For deep carious cavities, a preparation based on calcium hydroxide, for example, “Dycal” (Dentsply), is applied under the insulating lining.
7. Acid etching (conditioning) of enamel.
8. Application of enamel bonding agent.
The enamel bonding agent (Adhesive) is applied in a thin layer using a brush to the etched enamel surface and the insulating gasket (Fig. 292). Then carefully reduce the thickness of the layer using an air stream or a brush. In this case, it is not necessary to completely dry the bonding agent with air, since it is an unfilled hybrophobic resin and does not contain a solvent.
9. Photopolymerization of bonding agent.
10. Introducing composite filling material into the cavity and curing it.
11. Final processing of the filling; postbonding is acceptable. According to indications, the areas of enamel adjacent to the filling are fluoridated.
13. A follow-up examination of the patient and assessment of the quality of the restoration are carried out 2-3 days after treatment.
3-component - etching agent, primer, adhesive. Representatives: All Bond / Bisco, Solid bond / Kulzer, Solobond Plus / Voco, etc. These systems provide adhesion to dentine enamel of about 30 MPa;
2-component:
primer and adhesive in one bottle (self-priming bond), etching agent or conditioner - separately. Representatives: One Step / Bisco, Single bond / 3M, Gluma Comfort Bond I Kulzer, etc.;
Adhesive systems. Their main purpose is to ensure a tight and durable attachment of the filling material or artificial structure to the tooth tissue.
Adhesive systems are used when working with composites, compomers, ormocers, some polymer-based glass ionomer cements, and amalgam; for adhesive fixation of all types of indirect structures, repairing chips of composite and ceramic veneers, for sealing fissures and in orthodontics. It is necessary to distinguish between an adhesive system and an adhesive (substance).
An adhesive system is a set of substances used in strict sequence and providing surface treatment of tooth tissue for subsequent attachment of filling material or cement to it. The adhesive system consists of the adhesive itself (adhesive agent, bond, bonding agent) and substances that prepare the surface (acid, conditioner, primer). An adhesive system may include a single adhesive and surface preparation agent or several components applied alternately or mixed together.
Adhesive systems must meet the following requirements:
attach to tooth tissues;
attach to filling material or cement;
do not dissolve in oral fluid;
withstand cyclic mechanical and thermal loads.
There are adhesive systems for enamel, for enamel and dentin at the same time. The composition of the system can be one-, two- or multi-component; by curing method - self-curing, light-curing and double curing; depending on the filler content - filled or unfilled. If the adhesive contains acid, the system is called self-etching (“Xeno III”, Dentsply, “Etch&Prime 3.0”, Degussa).
Substances that prepare the surface can be divided into acids and primers.
Acid (mineral or a mixture of organic acids) is used to etch the enamel surface and clean the dentin surface from the “smeared” and partially demineralized layer. Surface treatment with acid is sometimes called conditioning. For this purpose, inorganic (orthophosphoric) and organic (citric, maleic, polyacrylic) acids can be used.
Primers can be a complex of surfactants, dissolved polymers, acids and other compounds that enhance adhesion. Primers can be either single-component or multi-component.
Sandwich technique , used in modern restorative dentistry, consists of using amalgam, cements, compomers or composites (liquid-flowing or chemical curing) with light-curing composite materials to restore a tooth destroyed by caries. The layer-by-layer application of these materials resembles a “sandwich”. The sandwich technique of layer-by-layer application of glass ionomer cement (GIC) as a thickened lining with a composite restorative material has been used for a long time. This technique utilizes the unique chemical adhesion inherent in glass ionomer cements to prevent marginal failure of the restorative restorative material. GIC is biocompatible with dental tissues. Due to the constant release of fluoride, they have a cariesstatic effect. They are resistant to oral fluid and have satisfactory mechanical strength. The GIC gasket helps reduce composite shrinkage. The use of this cement up to the enamel-dentin border makes it possible to use expensive restorative material much more economically. The use of GIC is reliable in providing the first two or three millimeters of the outer surface of the restoration where it contacts the gingival or subgingival margin of the cavity. GIC used in sandwich technology must be mechanically strong to withstand occlusal loads and have increased tensile strength (thereby resisting composite shrinkage). GIC must have sufficient working time, but set quickly, be insensitive to moisture, and radiopaque. The use of a thin and transparent layer of restorative material presupposes good aesthetic qualities and a sufficient number of colors of glass ionomer cement. The triple-curing GIC "Vitremer" (3M) we use, in addition to the listed qualities, has convenience and ease of use: the material is applied in one portion (the triple-curing mechanism, thanks to a patented microencapsulated catalyst, guarantees, with one-step application, optimal hardening even of those areas of the filling where light does not reach). "Vitremer" has a sufficient working time (3 minutes) and fast setting, which occurs as a result of exposure to light after 40 seconds. Triple curing provides improved physical and mechanical properties even when applying the material as a single mass.
