Dental Caries

Introduction

Importance of the theme

Dental caries is one of the most important global oral health burdens and is the most common childhood disease worldwide. It is also the most prevalent oral disease in several Asian and Latin American countries and has a significant impact on quality of life and public health.

Caries is a progressive disease that causes demineralization and destruction of the hard tissues of the teeth. It starts in the enamel as a white spot lesion. If it is not managed, cavitation will develop and will progress into the dentine. Deep carious lesion is a clinical diagnosis that is given when the carious process has penetrated deep into the dentine with possible pulpal exposure. Deep carious lesions cause pulpal inflammation (i.e., pulpitis); if not managed, they may result in pulp necrosis and involvement of the periradicular tissues, with possible pain requiring endodontic treatment or extraction. Deep carious lesions can be detected clinically and/or radiographically. Clinically, according to the contemporary International Caries Detection and Assessment System, (ICDAS) the most severe carious lesion is called “extensive” and is indicated by code 6 (on a scale from 1 to 6). An extensive carious lesion is both deep and wide, with visible dentine on the cavity walls and at the base; the carious process histologically involves at least half of the tooth surface or may reach the pulp. The carious lesion is classified as “active” when it has a yellowish color and a soft, moist consistency. A carious lesion is classified as “inactive” (arrested) when it is heavily pigmented, hard, leathery, and dry (Miller and Massler, 1962; Sarnat and Massler, 1965). Carious dentine consists of two layers: the outer layer, which has been infected by bacteria, has disintegrated, and is not able to remineralize due to the destruction of collagen, and the inner layer, which, although affected by 14 acids from bacteria (but not by bacteria itself) is able to remineralize, as the collagen texture is still intact. Radiographically, deep carious lesions are defined as those close to, but not into the pulp .There is no unanimous agreement about the depth that qualifies “a deep carious lesion”. Instead, a carious lesion is considered deep when pulpal exposure is anticipated during total caries excavation (Fitzgerald and Heys, 1991; Bjørndal et al., 1997). However, this has been shown to be subjective measurement, as radiographic depth might vary from half into the dentine to reaching the pulp (Bjørndal and Thylstrup, 1998). Radiographically, carious lesions penetrating halfway or more into the dentine (Maltz et al., 2013), into the inner third of the dentin , or into the inner fourth of the dentine have also been assessed as deep ( Massler and Pawlak, 1977; Bjørndal, 2010).

The treatment of deep caries lesions is associated with significant risks for the pulp, including pulpal exposure and postoperative pulpal complications, which might eventually compromise the retention of the tooth . Moreover, treating deep lesions might be associated with pain and subjective burden both during and after treatment, and might generate long-term costs due to retreatments being required.

Objectives of research

The overall aim of this thesis was to collect knowledge and provide a foundation about deep caries and its various treatment techniques and to discuss about a new and innovative obturation or filling material using SDR ( Smart dentin replacement) and its application in deep caries lesions .

The goals of this thesis were:

1.To study and learn diagnosis of deep caries

2.To learn etiological factors of deep caries

3.Particularities of treatment of deep caries

4.The use of SDR system and its benefits among other filling material

Chapter I.Analysis of the literature on the theme

1.1 Definition of deep caries

Deep carious lesion is a clinical diagnosis that is given when the carious process has penetrated deep into the dentine with possible pulpal exposure

The definition of deep caries can also be made by the x-ray, because it is within the clinical setting that the general dental practitioners will end up using the

findings of laboratory research, and therefore it is of paramount importance to have a reference that can be used in a clinical setting. As the depth of the caries lesion represents a diagnostic problem, it may be relevant to further classify it

Beyond previous attempts. The deep lesion has previously been defined radiographically as being within the pulpal quarter toward actual contact with the pulp. However, it is suggested separating the deep lesion in two scenarios. A deep caries lesion is defined as involving the pulpal quarter of the primary/secondary dentine (Figs. 9), but still with a radiodense zone separating the demineralized dentine. The extreme deep lesion involves the entire primary/secondary dentine either with no radiodense zone separating the demineralized dentine from the pulp or with a radiodense zone located within the pulp chamber indicative of tertiary dentine (Figs. 9.4a ).

A B

Fig. 9.4 The radiographic presentation of an extreme deep caries lesion versus a deep lesion. ( a ) The entire primary/secondary dentine is penetrated either with no radiodense zone separating the demineralized dentine from the pulp or with a radiodense zone located within the pulp chamber indicative of tertiary dentine. ( b ) The deep lesion involves the pulpal quarter with a radiodense zone separating the translucentzone from the pulp

1.2 Pathophysiology of dental caries

The pathophysiology of dental caries is a very complex reaction and it cannot be explained in terms of a single event or observation. For this purpose, the process of dental caries is often explained with the help of many theories.

Major theories of dental caries

• Acidogenic theory

• Proteolytic theory

• Proteolytic chelation theory

• Sucrose chelation theory

• Autoimmune theory.

ACIDOGENIC THEORY:

This theory is also known as Miller’s chemicoparasitic theory as it was first postulated by WD Miller in the year 1889 and it proposes that “acids formed due to the fermentation of dietary carbohydrates by oral bacteria lead to progressive decalcification of the tooth structures with subsequent disintegration of the organic matrix”. Therefore, acidogenic theory states that the process of dental caries involves two stages:

Initial stage: Production of organic acids occurs as a result of fermentation of carbohydrates by the plaque bacteria.

Late stage: The acids cause decalcification of enamel followed by dentin and thereby cause total destruction of these two structures along with dissolution of their softened residues. The final result is the loss of integrity of the

tooth structures at a particular point on the surface with formation of a cavity. According to Miller, there are four important factors, which can influence the process of tooth destruction in the process of dental caries and these factors are as follows:

A. Dietary carbohydrates

B. Microorganisms

C. Acids

D. Dental plaque.

Proteolytic theory :

The proteolytic theory of dental caries was first proposed by Gottelib in 1944 and this theory states that, the proteolytic enzymes liberated by cariogenic bacteria cause destruction of the organic matrix of enamel. As a result of that, the inorganic crystals of the enamel get detached from one another and finally the whole structure collapses, leading to a cavity formation.

The concept of proteolytic theory was further extended by Pincus in 1949 and he proposed that the “sulfatase enzyme” liberated by gram negative bacilli, hydrolyze the sulfated mucosubstances of enamel matrix and thereby liberate sulfuric acid, glutamic acid and aspartic acid, etc. which dissolve the mineral portion of the enamel.

The scope of the proteolytic mechanism in initiating the enamel caries is very limited because the organic (protein) content of enamel matrix as such, is very scanty. However, this mechanism can be a more appropriate one in cases of dentinal and cemental caries.

Proteolytic chelation theory:

The proteolytic chelation theory explains the process of dental caries in the following way, during caries, first of all proteolytic breakdown of the organic portion of the enamel matrix takes place. Following this, a chelating agent is formed by the combination of proteolytic breakdown products, acquired pellicle and food debris, etc which facilitates tooth decay. The whole process is helped by the bacterial enzymes which facilitates tooth decay. The chelating agent, which is formed, is always negatively charged (mostly due to its protein content) and it releases the positively charged calcium ions (Ca++) from the enamel or dentin. This process is called chelation, and it eventually results in tooth decay. So, the chelation can be defined as a process that involves the complexing of a metallic ion to a complex substance by a coordinate covalent bond, which results in a highly stable, poorly dissociated and weakly ionized compound called chelate. The proteolytic chelation theory explains that the destruction of the organic matrix of the enamel as well as its mineral parts both occur simultaneously and interdependently.

Sucrose chelation theory :

Sucrose chelation theory proposes that ‘very high concentration of sucrose in the mouth of a caries active individual may result in the formation of complex substances like calcium saccharates and calcium complexing intermediaries, etc. by the action of phosphorelating enzymes’. These complexes cause release of the calcium and

phosphorus ions from the enamel and thereby result in tooth decay.

This theory is unlikely to be a significant because once the sucrose is in the oral cavity, it readily gets metabolized to form acids, and there is hardly any scope for formation of calcium saccharates, etc. Moreover, for the formation of calcium saccharate, a very high level of pH is required, the range which is never achieved in the oral cavity.

Autoimmune theory:

The autoimmune theory of dental caries suggests that a few odontoblast cells at some specific sites, within the pulp of a few specific teeth are damaged by the autoimmune mechanisms. For this reason, the defense capacity and integrity of the overlying enamel or dentin in those specific areas are compromised, and they can be the potential sites for caries development in future.

1.3 Histology of deep Caries Lesions

In 1980, Takao Fusayama published the research carried out by his team at Tokyo Medical and Dental University on the analysis of deep caries lesions. Using histologic, biochemical, biomechanical, microscopic, and microbiologic techniques, the researchers were able to distinguish two layers in caries lesions that were very different in nature. The first layer was named “outer carious dentin.” It was highly infected, acidic, and demineralized. The collagen fibrils in this layer were denatured, having lost most of their intermolecular cross linkages. This layer was not sensitive to contact and could be removed without anesthesia because it had lost the hydrodynamic system of intact dentinal tubules. This layer also failed to remineralize in a natural way because the collagen framework could not return to normal even if the acid environment was neutralized. The second layer was termed “inner carious dentin.” This layer was partially demineralized and slightly infected,

but the collagen fibrils retained their natural structure around intact dentinal tubules. Because of this remaining structural integrity, the inner carious dentin was sensitive to removal without anesthesia. The lumens of the dentinal tubules in this layer had no peritubular rings of hydroxyapatite [Ca10 (PO4)6 (OH)2]. Instead, the enlarged lumens were now partially or completely filled with large crystals of tribeta calcium phosphate [Ca3 (PO4)2] called Whitlockite. Whitlockite

is crystallized into the dentinal tubules as hydroxyapatite is dissolved from intertubular dentin by bacterial acids. This inner layer of the caries lesion was able to be restored to a normal mineralization with a hydroxyapatite matrix surrounding the collagen fibrils (intertubular dentin) and around the tubules (peritubular dentin) when the pH was neutralized. Since the late 1960s, the goal of removing only outer caries and saving the inner caries for remineralization has been recognized. The problem was that each operator had a different sense of hard and soft. Clinically finding the interphase between the outer and inner carious dentin layers Pulpal status in relation to deep carious lesions was inconsistent. Adding to the difficulty was the anatomical softening of dentin as it nears the pulp (reparative dentin, laid down during the caries progression, is even softer than deep dentin) and the fact that different instruments (hand, rotary, or ultrasonic) removed more or less of the lesion during excavation. All of this subjectivity and variability made for inconsistent caries removal end points. Fusayama made progress toward a solution to this problem by finding two propylene-glycol–based colored solutions (one purple, one red) that stained the outer and inner carious dentin layers differently. The outer carious dentin stained dark red, and the inner carious dentin stained lighter (pink for the red dye formula). The interphase between the outer and inner carious dentin was referred to as the turbid layer. This interphase is a mixture of parallel groups of tubules, some of which are outer carious dentin and some of which are inner carious dentin (depending on how long the tubules have been infected and under the influence of bacterial acids). Under the turbid layer, the inner carious dentin becomes the transparent zone. The transparent zone is translucent in histologic examination with a light microscope. The pink staining (often referred to as a pink haze) in the turbid layer becomes lighter as it moves into the transparent zone. In this zone, the large lumens of the dentin tubules are filled to some degree with Whitlockite. These large crystals slow bacterial invasion and reduce dentin permeability. This reduced permeability decreases the outward flow of pulpal fluid, which is referred to as “transudation.” It also reduces the movement of pulpal fluid caused by temperature changes. Underneath the transparent zone is an interphase of the transparent zone, as well as normal sensitive dentin called the “subtransparent zone” (Fig 4). The subtransparent zone stains even more lightly than the transparent zone. Removal of the transparent and subtransparent zones in an attempt to reach hard dentin is the cause of most pulp exposure (Fig 5).

Fig 4  The deep caries lesion has two parts: outer Fig 5  By using only visual and tactile

and inner carious dentin. The inner carious methods for deep carious removal dentin has three parts: the turbid layer, the the pulp is often exposed because

transparent zone, and normal dentin the transparent zone , subtransparent

zone normal dentin, reparative dentin

are all softer than superficial and im dentin

1.4 Diagnosis and prognosis of deep carious lesions

Unfortunately, our available diagnostic tools are not sufficiently reliable to get an exact picture of the involved tissues and tooth, however, by combining the results of the following clinical tests and observations we can gain a good diagnostic perspective.

Pain:

The absence of pain cannot be used as deciding criteria for the status of pulp dentin organ although the teeth with non-vital pulp dentin organ are frequently painless.

The presence of pain may serve as guiding criteria for the status of pulp dentin organ, although this is not reliable. For e.g. when pain at night or spontaneous pain not initiated by thermal or chemical stimulation of the pulp dentin organ could indicate possible destructive degenerative changes in the pulp dentin organ. However, pain initiated by thermal or chemical stimulation of the pulp dentin organ that disappears immediately after the removal of the stimulation is a possible indication of a much less degree of degenerative changes. Any symptoms of pain should be recorded in patient’s own words.

Radiographs:

Radiographs give a two-dimensional image of three-dimensional structures. Radiographs, especially periapical radiographs, can be a very practical supporting tool. A radiograph can indicate:

The thickness of the dentinal bridge (effective depth) can be estimated. It should be emphasized that the extent of the carious lesion as shown in the radiographs will always be less than the actual size of the lesion .

The thickness of the periodontal ligament space with an intact lamina dura , especially periapically will indicate increased vascularity and consequently increased activities of the pulp dentin organ, discontinuity in the lamina dura may indicate more advanced activities of the pulp dentin organ, possibly destructive in nature .

The location of the caries con tip relative to the anatomy of the pulp chamber and root canal system. Caries cones proximate to constrictions in the pulpal or root canal tissues will profoundly affect the design of the cavity preparation and the choice of an intermediary base.

The gross evaluation of mineralization and consequently the permeability of the involved dentin, we can radiographically identify sclerotic dentin, which will appear radiopaque, and tertiary dentin, which will appear as a localized thickening of the dentinal bridge, pulpal to the lesion, creating irregularities in the pulp chamber or root canal walls and/or roof. This data is very important in determining the reparative capability of the pulp dentin organ and the type of intermediary base to be used.

Thermal testing:

Using heated gutta percha sticks or cold test using cotton pellet soaked in ethychloride, or liquid nitrogen.

Electric pulp testing :

If the required energy is higher in the controlled teeth, this is an indication of possible acute changes in the pulp dentin organ of the affected tooth and vice versa

1.5 Treatment of deep carious lesions

The treatment of deep carious lesions presents a significant challenge to the practitioner because of the risks for the pulpal exposure and postoperative pulpal complications that jeopardizes the vitality of the tooth. The traditional management of deep dentin caries is removing of all infected and affected dentin to prevent further cariogenic activity to provide a well-mineralized base of dentin for restoration.

In recent years, with the advent of dental materials and the subsequent developments in minimal cavity design, this widely accepted principle has been challenged and is now considered as a too destructive method for caries removal. It is clear that when the remaining dentin tissue is reduced, the risk of pulp pathology and loss of vitality are higher.

There are several techniques available for removing decayed tissue and restoring the tooth. Currently, other than direct complete caries excavation, two main techniques have been advocated as stepwise excavation and partial caries removal. Stepwise excavation is a technique by which caries is removed in two separate procedures. In the first procedure, only the peripheral caries is completely removed, but no attempt is made to remove soft carious dentine on the pulpal wall, due to the risk of pulp exposure. It is suggested that after 2–24 months, the cavity is re-opened, the remaining caries is excavated, and the tooth is restored permanently.[8] Partial caries removal is a technique where incomplete caries removal is followed immediately by placement of a final restoration. In many studies, direct complete caries excavation was the preferred treatment method and has been regarded as the gold standard in cavity preparation.

Several studies were published comparing complete or stepwise excavation, or treatment preferences of dentists in the case of deep dentin caries. Bjørndal et al. tested the effects of stepwise versus direct complete excavation and recommended stepwise excavation approach for managing deep caries lesions.

Traditional Complete Caries Removal (Removal Of All Soft And Leathery Dentin) vs. The Conservative Approach To Partial Caries Removal

The traditional caries removal technique (Fig. 1) involves the removal of all soft and leathery dentin until hard dentin is reached before placing a final restoration. In shallow to moderate dentinal cavitated caries lesions (that radiographically appear to extend less than 75 percent into the dentin) this technique is often used without the risk of exposing the pulp (Table 1)

Traditional complete caries removal

Fig1a.Initial composite resin Fig1b. Rubber dam isolation Fig1c. final composite resin

With recurrent caries composite removed and restoration

complete caries removed.

Deep caries lesions are cavitated caries lesions that radiographically extend more than 70 to 75 percent into dentin. When the traditional caries removal technique is used to treat the deep caries lesions of vital asymptomatic teeth, the risk of pulp exposure is high. Complete removal of the soft and leathery dentin may cause a pulpal exposure, introducing bacteria into the pulp. Such outcomes require either root canal therapy or extraction (Fig. 2). Evidence indicates that the traditional complete caries removal procedure may be detrimental to the pulpo-dentinal complex and does not take into consideration the biological natural response of the tooth to the caries stimulus.

Fig2. Clinical case of pulpal exposure Table 1
during complete caries removal

Pulp exposures can be due to mechanical reasons, caries or trauma. When the pulp exposure of a vital asymptomatic tooth is mechanical or due to trauma, the Direct Pulp Capping procedure has been used in an attempt to preserve tooth vitality. After rinsing and disinfecting the exposure site, a liner usually from calcium hydroxide or MTA material is placed directly over the exposed pulp followed by a sealing liner of resin modified glass ionomer and the final restoration. It is thought that pulp exposures due to trauma or mechanical reasons (iatrogenic) have a better success rate than a caries exposure since there is no bacterial contamination. When the pulp is exposed due to caries, the bacterial contamination will cause inflammation, decreasing the healing ability of the pulp and resulting in irreversible damage or necrosis. In deep caries lesions of asymptomatic, vital restorable teeth the pulp exposure should be avoided; it is preferable to use an incomplete caries removal approach rather than the direct pulp treatment.

In these specific cases the option of treatment using a more conservative approach to caries removal is indicated, in an attempt to avoid pulp exposure and maintain pulp vitality. The use of incomplete caries removal techniques have been proposed based on the deeper understanding of the biological response of the tooth to caries stimulus and the structural changes that occur as a protective response of the tooth to bacterial invasion.

The incomplete caries removal technique involves the partial removal of soft caries infected dentin starting peripherally (at the DEJ) and the sealing of the remaining caries lesion with an interim or final restoration (in one or two visits) with the goal to seal the partially demineralized affected dentin and arrest or reverse caries lesion progression.

There are different techniques of incomplete caries removal described in the literature. The most widely known and used techniques are the Indirect Pul
p Treatment (formerly termed as “capping”)9 and Stepwise Caries removal. They differ in the amount of soft dentinal tissue removed, number of appointments involved (one or two), and restorative materials. Each technique has indications, advantages and limitations. To properly utilize these techniques for different clinical situations, tooth and pulpal diagnosis is crucial, as well as the understanding of the caries lesion activity, and related changes in the dental structures.

Fig4. Decision tree for conventional caries removal vs incomplete caries removal.

The extent to which the carious dentin should be removed is an important decision for the clinician before placing a restoration, especially in deep caries lesions where the vitality of the pulp can be compromised. Although some morphological studies have shown a defined boundary between the highly caries infected and the caries affected dentin, clinically this presents a subjective and difficult decision regarding the amount of dentin that should be excavated. Some studies have shown that is not possible to eliminate all the micro-organisms even during a conventional caries removal, as a few bacteria will remain even after all soft dentin is removed. However, studies that have evaluated activity and progression of lesions restored with remaining infected dentin, have shown that the majority of the lesions appeared to be arrested both clinically and radiographically and showed a decrease or absence in micro-organisms with time. Therefore, a conservative approach to caries removal is suggested when removing caries over the pulpal surface in asymptomatic deep caries lesions. Discolored, leathery dentin (identified with scrapping spoon, not poking with the explorer) can be left once the cavity floor is reasonably firm to avoid the risk of pulp exposure. Good sealing with restorative materials that enhance the dentin’s potential to remineralize are recommended. Providing a good restoration seal has been suggested to be key in arresting and preventing caries progression.

Case selection and preliminary planning of the procedure are critical steps in achieving success using any techniques of Incomplete Caries Removal for the treatment of deep caries lesions. The diagnosis is very challenging because it is based on clinical symptoms and it is very difficult to know the real status of the pulp. For example, a tooth with pulp severally damaged may respond to pulp testing in a similar way to normal or reversible pulpitis, and may progress to necrosis without significant signs or symptoms. A detailed preliminary assessment as well as long-term pulpal/periapical evaluation (pulp test, radiographs, signs and symptoms) is necessary when doing Incomplete Caries Removal.

Indirect pulp treatment
ITP consists in the removal of all peripheral soft dentin of the deep caries lesion, leaving a thin residual layer (0.5mm–1.0mm) of leathery affected dentin over the pulpal floor or axial wall followed by a liner and placement of the final restoration with the goal of preventing pulp exposure. This is a paradigm shift for many practitioners and a topic that can create controversy.

Several studies compiled in current systematic reviews have demonstrated that the use of incomplete caries removal techniques significantly decreases the risk of pulp exposure in deep caries lesions compared with the traditional complete caries removal procedure, and these restorations have shown similar success.

It has been also shown that if there are any remaining bacteria after the caries is partially removed, the placement of a restoration providing a good seal will arrest the lesion progression by isolating the bacteria from the substrate and decreasing acid production. These findings have been observed in microbiological studies and also by using clinical assessment of the color changes of the lesions from light yellow brown to dark brown and the tissue consistency from soft wet to hard and dry assuring the arresting of the caries lesion (Table 2).

TABLE 2. 

Figure 5 shows a clinical sequence of Indirect Pulp Treatment.

Fig5a. after proper clinical Fig5b. Peripheral caries Fig5c. finish cavity

Radiographic diagnosis to removal preparation and liner

Confirm(+) vitality RD isolation application

And proper access to dentinal lesions
Figure 5d. composite resin final restoration

Stepwise caries removal
Stepwise excavation is an alternative technique for removal of deep caries lesions that radiographically involve 75 percent or more of the total dentin thickness and do not already penetrate to the pulp. The purpose of the stepwise excavation approach is to change the cariogenic environment of deep caries lesions by removing only the soft wet infected dentin and then sealing the remaining demineralized dentin with an interim restoration. The goal is to arrest the active caries lesion and stimulate dentinal tubule sclerosis and the formation of reparative dentin while maintaining pulp vitality.

FIGURE 6 Clinical sequence of Stepwise Caries Excavation (first visit)

Fig 6a. Diagnosis vitality test Fig 6b. RD isolation, access

(+), periapical radiograph peripheral caries removal

Show deep recurrent caries maintaining leathery dentin

The difference between Stepwise Caries Removal and Indirect Pulp Treatment is that the stepwise procedure is performed in two visits (usually months apart). In the first visit, the soft necrotic carious dentin is removed partially and peripherally and the tooth is sealed with an interim restoration. The time interval between the two visits allows remineralzation to occur and tertiary dentin to develop. At the second visit, the tooth is re-entered, the residual affected soft dentin is removed and
the final restoration is placed. Two recent systematic reviews, Rickets et al14 and Schewendicke et al,16 have compiled and analyzed the evidence suggesting that there are potential benefits to reducing the risk of pulp exposure in using either one or two steps techniques compared with complete caries removal. There is still a need of more evidence and good standardize clinical research to determine whether is necessary to re-enter.

Clinical sequence of Stepwise Caries Excavation, second visit (after one year).

Fig 6e. Rd isolation , GI Fig 6F. GI liner, vitrobond

Removal, dentin evaluation and finish cavity preparation

To be able to do a good case selection, it is important to consider the lesion activity and its relationship with the status of the cavitated lesion. In a closed environment lesion, the bacterial ecosystem is very active, causing extensive demineralization and the lesion is rapidly progressing. Clinically this dentin usually has a yellow light color and is very soft and wet. Trying to remove most of the soft dentin to produce a good preparation in this situation will need extensive removal of the tooth structure. During the attempt to leave only a residual thin affected dentin over the pulpal floor or axial wall, the pulp may be exposed. In these rapidly progressing lesions no protective changes in dentin occur and the odontoblast may be irreversibley affected. On the other hand, the fast removal of this very soft dentin may cause more inflammation to the pulp and it can itself induce bacterial contamination. In these clinical situations the consideration of doing the caries removal in two steps is indicated, allowing time for the lesion to arrest as well as facilitating the process of dentin sclerosis and pulp repair.

Figure 7- Clinical case using Stepwise Modified Technique, first visit.

Fig 7a. Diagnosis, vit Fig 7b. RD isolation, Fig 7c. Peripheral caries

Tests (+), PA radiograph access to caries lesion removal maintaining thick

Showing deep dentinal layer of affected dentin over

Caries on tooth #2.5 pulpal and axial wall.

Fig 7d. Application of fuji liner Fig 7e. Interim DO restoration

On pulpal and axial wall fuji IX extra.

Clinical case using Stepwise Modified Technique, second visit (after six months).

Fig 7f. Diagnosis vit test Fig 7g. RD isolation, Fig 7H. Partial removal

(+), PA radiograph showing GI restoration of GI leaving G margin sealed

Normal structures for open sandwich technique

During the second visit a much better environment and solid structure is found allowing less removal of tooth structure during final preparation and providing an optimal environment for the placement of a final restoration. If during the re-entry appointment it is found that the interim restorations are well attached and provide a good seal as in the case of using glass ionomer cements, the arresting of the lesion is expected and there is no need for their complete removal. Therefore, it is suggested to partially remove the interim restoration maintaining the internal liner material with the purpose to prevent a pulp exposure during this second step. The walls can be refined and the preparation modified depending on the material selection for the final restoration. This is a suggested modification on the stepwise technique (Fig. 7). One of the major drawbacks for the stepwise excavation technique is the lack of patient compliance. If the patient does not come back for the second appointment where final restoration is placed, the interim restoration may start leaking or breaking down, thereby compromising the treatment success.

In contrast, in an open environment lesion, the dentin has been exposed to a remineralization process in the presence of minerals from saliva and fluoride and its progression is slow. This slow process may allow protective changes in dentin and pulp to occur such as: tubule sclerosis, reduced dentinal permeability and formation of protective tertiary dentin. Clinically a dark brown dentinal color is observed and the consistency of this dentin is more leathery and dry. In these clinical scenarios, there is a more solid substrate where the arresting of the lesion has happened naturally. This allows for conservative caries removal while achieving a good solid structure for the placement of a final restoration. In these situations the caries removal in one visit is more appropriate as in the case of Indirect Pulp Treatment.

TABLE 3.

Technique for stepwise excavation
After a detailed evaluation and correct case selection using the previous criteria, the stepwise approach is performed in two separate appointments with an interval of six to eight months.

First Appointment

1. Inform the patient about the treatment options including benefits and possible drawbacks. Allow the patient to be part of the decision.

2. Rubber dam isolation is highly recommended.

3. Access to the caries lesion, peripherical excavation should be completed by cleaning the DEJ, removing the very soft, necrotic and infected dentin and leaving the soft, discolored yellow or dark leathery dentin over the pulpal floor and axial walls. Avoid excavating close to the pulp during this first step to reduce the risk of pulp exposure.

4. Restore with a temporary glass ionomer material. For example, first use Fuji Triage GC® as a liner (color coded for re-entry) and then place Fuji IX or Fuji II LC GC® as a restorative material.

5. Schedule appointment (six to eight months) for re-entry.
Second Appointment (Re- Entry)

1. Re-evaluate history of symptoms.

2. Clinical exam to evaluate for swelling or tenderness.

3. New periapical radiograph to verify lack of pathosis.

4. Pulp vitality tests (CO2 and EPT).

5. If all of the above are normal isolate teeth, preferable with Rubber Dam.

6. Remove the sedative filling peripherally first and then be especially careful when approaching the Fuji Triage liner. The Fuji Triage does not need to be completely removed if arrested and well-sealed dentin is observed, it may be maintained over pulpal and axial wall to prevent pulp exposure.

7. Dentin assessment (peripheral) and careful removal of any remaining soft dentin.

8. Placement of glass ionomer liner over the exposed dentin (Vitrebond 3M®)

9. Restore with the material of choice for final restoration.

10. Six month recall for evaluation of vitality tests and periapical radiograph.

11. Continue with similar annual recalls.

1.6 The Role of the Restorative Dental Material

The dental material to restore a tooth has a significant role in the success of the operative procedure and on the long term outcome. Thus, the practitioner’s work with a particular tooth will be ended by the end of the session, while the effect of the material on the surface it restores begins. Therefore, it is very much logic to focus at the requirements we need in a material to restore a deep dentinal lesion. It is obvious from the following that the restorative material interacts with the tooth tissue in many different ways. For example, sealing properties of a dental material are considered to be the most important properties in preventing caries progression or/and recurrent caries. At the same time, the bacteriostatic properties would be beneficial for eliminating or at least reducing the number of residual bacteria left in the cavity.

However, it is claimed that reduction can be achieved by just sealing the cavity . Another way of interaction is the remineralizing effect that the material can exert on the dentin surface. The figure illustrates clearly that there is no independent factor responsible for the success or failure of a restoration. Instead, it is the vital, sensitive, essential and precise interaction between the operator knowledge, skills, facilities and

sense with an improved adhesive material that is qualified to the roles (sealing, antibacterial, remineralizing) it will play in the cavity. These together with the available tooth substrate bearing in mind the individual patient related factors will influence the end results of the dental operative procedure.

1.7 Smart Dentin Replacement (SDR) and deep cariuos lesions :

The Science of Composites

Composites are usually classified by filler particle size. The groups most widely used today are hybrid, microhybrid and microfilled composites. Nano-filled composites like Ceram•X™ mono+, the DENTSPLY product used in this case, extend this classification. The mean filler particle sizes are 1-10 µm in hybrid composites, < 0.4 µm in microfilled composites and 0.4-1 µm in microhybrid composites. Nano-filled composites contain nanoparticles with an average size of approximately 2.3 nm, nanofillers with an average size of approximately 10 nm and glassceramic fillers with an average size of approximately 1 µm. Composites can also be classified by consistency or function. This type of classification distinguishes between anterior, posterior (universal) and flowable composites. Anterior composites permit restorations with a truly natural appearance, if perfectly layered, and can be polished to a high, long-lasting shine. Universal composites provide adequate mechanical stability and aesthetics for use in premolars and molars and may even be aesthetic enough for very good anterior restorations when applied incrementally. The incremental technique involves increased effort, but it has to be used to ensure proper polymerization and high marginal integrity. Flowable composites have so far been used only in thin layers for cavity lining, extended fissure sealing or Class I restorations in non-stress-bearing areas, due to their great volumetric shrinkage, resulting in high polymerization stress, and their insufficient compressive strength and low abrasion resistance. Since low-viscosity composites offer both a large variety of potential applications and easy and time-saving dosage and placement, DENTSPLY has developed this material type into a “universal composite” for posterior restorations and launched it under the brand name SDR™.

Features and Benefits of SDR™

SDR™ is a low-viscosity, light-cured composite restorative. It has a flowable consistency, but differs from conventional flowables in practical use with regard to its physical parameters. The proportion of glass fillers is 68% by weight. SDR™ helps to rationalize inventory management, because it is available in only one translucent shade, which nevertheless matches the surrounding tooth structure very well. Besides, the aesthetic quality of the final result is determined mainly by the shade match of the composite layer capping SDR.

Benefits of SDR in deep carious lesions

The application properties of SDR are especially advantageous when incremental placement is not possible or desirable, cavities are very deep and narrow, especially in the proximal area, and composites are hard to adapt with a spatula. In these clinical situations, I have often had difficulty trying to place composite restorations that are free of gaps and voids and show a good marginal seal. It can be very frustrating to see that although a great deal of time and effort has been invested, the result is not perfect and needs reworking.

SDR™ has been developed specifically for dentin replacement in Class I and II cavities and can be bulkplaced and cured in increments of up to 4mm after cavity treatment with an adhesive. The polymerization stress, i.e. the main factor responsible for the quality of the bond to the adhesive layer, has been reduced by 50% or more, as compared to competitive products. The low viscosity ensures perfect adaptation to the cavity walls, even in difficult-to-access areas. In order to maximize abrasion resistance and compressive strength in the posterior region, the enamel layer is conventionally restored with a 2mm increment of a universal or nano-filled composite, e.g. Ceram•X™, Esthet•X HD® or Spectrum® TPH®3. The benefits of SDR™ include a quick, simple and costeffective application technique, a very low polymerization stress value of only 1.5 MPa (average value of flowable composites: 3-4 MPa), a maximum increment thickness of 4mm, and compatibility with all methacrylate-based adhesive systems. The decisive step in the development of SDR™ as a bulk-fill composite for dentin replacement was the reduction of polymerization stress by special polymerization modulators. These interact with the photoinitiator camphorquinone and distribute and decrease the stress within the material, without reducing the rate of polymerization or the degree of double-bond conversion. In a study conducted at the University of Mainz, Germany, the researchers came to three main conclusions: The shrinkage stress of SDR™ is significantly lower than that of two leading flowables. The low viscosity of SDR™ does not result in high shrinkage stress, in contrast with all tested low-shrinkage composites. SDR™ has clear advantages in terms of handling properties, especially in small cavities and in cavities with undercuts, where air bubbles are more likely to be trapped when using universal composites.

SDR™ is based on the chemistry of conventional universal composites and therefore, a certain adhesive or a combination of a special material for occlusal coverage is not necessary. The main difference lies in a modulator that is incorporated into a urethane-based dimethacrylate. With this, a conventional network structure is built from conventional monomers and the SDR™ monomer. The difference is not that the modulator becomes a part of the polymerized network but that it influences its development and, especially, how quickly the network is built. With this, polymerization stress is reduced from the very beginning.

Besides low polymerisation stress it is important to have a high depth of cure. This is achieved with one universal shade with sufficient translucency. Samples prepared with different layer thickness have been tested after a curing time of 20 seconds. Successful curing is achieved when the hardness of the lower side of a sample reaches a minimum of 80% of the upper side.

The combination of very low polymerization stress, along with a high depth of cure, allows layering in 4mm increments. This simplified procedure with SDR™, in comparison to conventional flowable composites, is shown in figure 5

Fig. 5 Conventional layering technique with composites vs. Simplified filling technique with SDR™.

Representative for many other studies regarding the compatibility (of SDR™) with adhesives and composites for the capping layer is the result of a chewing simulation shown below. Incrementally layered fillings (adhesive and composite of the same manufacturer) were compared with simplified filled cavities using the same bonding agent and composite and additionally SDR™, before and after chewing simulation regarding their marginal quality. All cases showed that using SDR™ in 4mm layers and capping with a universal composite, provides the same level of marginal quality compared to a restoration using incremental layering.

Chapter II Materials and research methods

The study was performed on 12 patients 8 (66.6 %) male and 4 (33.3 %) female. Secondary caries it were present in the class I by Black 9 cases (75 %), class II by Black 2 (16.6 %) and class III by Black 1 (8.3%).

2.1Methods of examination and diagnosis

Patient’s complains.

Direct visual examination.

Tactile “ probing”,percussion,thermalexam”cold,hot”.

Radiographs.

Dental floss .

Transillumination.

Electronic caries detector.

Direct visual examination :

Surface discoloration.

The grey appearance of enamel undermined by caries.

A frank cavity, or hole in the pitted enamel “ late stage”.

Tactile “ probing” :

A probe may be used gently to remove any plaque from the fissure but should not be pressed into the fissure.

Electro-odontometry (EOD)

Radiographs:

Bite-wing radiographs are of great importance in the detection of occlusal caries in dentin, although enamel caries cannot be seen.“ enamel remineralization”.

Diagnostic methods based on Laser:

1-Quantitative laser fluorescence (QLF)

It is a computer based method utilizes the blue green light from argon laser.

It allows early detection of caries and monitoring the de- and remineralization process.

It is not suitable for measuring dentin demineralization.

(a) White light image of early buccal caries effecting the maxillary teeth,

(b) QLF image taken at the same time as (a)

(c) 6 months after the institution of an oral hygiene programme , the lesions have resolved.

2-Diagnodent:

It aids the diagnosis of occlusal caries as an adjunct to visual inspection and radiographic examination.

It is a battery quantitative diode laser

fluorescence device

The intensity is displayed as numeric value

Diagnostic methods based on ultrasound

Using the ultrasound waves which travel across the surface of the tooth along the interface between enamel and air, rather than through the tooth structure.

Ultrasound may be a quick and reliable tool for the detection of dental caries in enamel.

Caries detection dye: (CDD)

It is simply filling the voids in enamel and dentin that are created by acid attack, or filling voids present in hypomineralized enamel.

The mechanism of differential staining does not involve selective chemical bonding of the dye in usual staining, but the selective penetration of the dye

2.2 Materials used in the treatment

For removal of soft and hard deposits sub gingival and supra gingival we used scaling and for plaque removal we used brushing professional with paste ,,Polident’’.

For rainfall irrigation we used antiseptic solutions (chlorhexidine 0.06%, hexoral).

For filling of secondary caries cavity it was used :

Calcium hydroxide light cure Cal LC (in deep caries)

Baseliner SDR

Nano composite Gradia direct and G-eanial from GC

Chapter III. Personal, experimental and clinical part

Clinical cases I

Medical card nr. 648

I. General data

Name, surname: I. S.

Place and date of birth: 09.11.1982

Sex: Male

Address: Chisinau

II. Subjective examination

Accuse: change in color of the teeth along with the time, which causes esthetic discomfort, pain to thermal excitatory.

History of present disease (anamnesis morbi): From the words of patient's the color changes appeared about half a year ago there where was treated dental caries. To the dentist not addressed.

History of life (anamesis vitae): Patient has grown in normal conditions, viral hepatitis, infectious diseases, tuberculosis, venereal diseases, AIDS – denies

Food and drug intolerance – denies.

Epidemiological anamnesis: Last 6 months parenteral treatment not received, in contact with contagious diseases has been away.

III Objective exam

Status praesens: General condition of the patient normal, clear knowledge. Skin is normal color, clean, no rash. Normostenic constitutional type. Active attitude. Normal facial expression.

Status localis

Exobucal exam:

Symmetrical, round. Report floors face in the normal height of equal size. Pink-pale skin clean, no pathological changes. Mouth opens normal. On palpation of the TMJ patient shows no pain condyles trip is uniform without pathological noise. Soft tissue palpation is painless, without pathological formations. Regional Lymph feel it’s not. Exit points of the nerves are painless.

Endobucal exam: Red edge of the lip are pink. scales and crusts are not present. Vestibule is of medium depth. Labial Frenulum are of the medium type (4 mm) from the top of papilla.

Jugal mucosa are pale pink, without pathologic elements. Gingival mucosa with the same color pale pink.

Dental inspection

Orthognatic occlusion

Dental formula

Percussion of teeth

Longitudinal or transverse moderate tooth is followed by a muffled sound, matte characteristic sign of teeth periodontal disease. Percussion in the axis are painless.

Complimentary exam

Thermal diagnosis – pain to thermal excitatory.

IV. Diagnosis

Based on complaints of patient's history and examination subjective and objective of disease is diagnosed by: Chronic deep caries tooth 26

Local:

Removal of soft deposits from the mouth by using scaling, plaque removal using the professional cleaning.

Rainfall irrigation with antiseptic solutions (chlorhexidine 0.06%, hexoral).

Anesthesia with ubistezin 4% -1.7ml

Initial look of tooth 26 after isolation

Fig. II. 2.1.1 before treatment

Preparing working tools (materials and instruments)

Fig. II. 2.1.2 Working tools

Professional cleaning of tooth 26

Preparing of the cavity

Medicamentos cleaning with H2O2 – 3%

Washing and drying with easy jet air

Applying matrix

Fig. II. 2.1.3 Applying matrix t26

Etching, Bonding 3 in 1and light cure for proximal margin

Restore the wall with Gaenial Flow

Indirect capping with hydroxide of calcium Cal LC photo

Baseliner SDR and LC

Fig. II. 2.1.4 Applying SDR t26

Etching, Bonding 3 in 1and light cure

Filling cavity with composite Gradia Direct

Fig. II. 2.1.5 After obturation tooth 26

Polishing the obturation

Fig. II. 2.1.6 Polishing

Final view

Fig. II. 2.1.7 Final view

Patient education for correct cleaning and maintaining oral hygiene.

Fig. II. 2.1.8 Correct tooth brushing

2.2 Clinical cases II

Medical card nr. 1211

I. General data

Name, surname: I. D.

Place and date of birth: 27.04.1982

Sex: Female

Address: Chisinau

II. Subjective examination

Accuse: change in color of the teeth along with the time, which causes discomfort esthetic, pain to mechanical, chemical, thermal excitatory.

History of present disease (anamnesis morbi): From the words of patient's the color changes appeared about half a year ago there where was treated dental caries. To the dentist not addressed.

History of life (anamesis vitae): Patient has grown in normal conditions, viral hepatitis, infectious diseases, tuberculosis, venereal diseases, AIDS – denies

Food and drug intolerance – denies.

Epidemiological anamnesis: Last 6 months parenteral treatment not received, in contact with contagious diseases has been away.

III Objective exam

Status praesens: General condition of the patient normal, clear knowledge. Skin is normal color, clean, no rash. Normostenic constitutional type. Active attitude. Normal facial expression.

Status localis

Exobucal exam:

Symmetrical, round. Report floors face in the normal height of equal size. Pink-pale skin clean, no pathological changes. Mouth opens normal. On palpation of the TMJ patient shows no pain condyles trip is uniform without pathological noise. Soft tissue palpation is painless, without pathological formations. Regional Lymph feel it’s not. Exit points of the nerves are painless.

Endobucal exam: Red edge of the lip are pink. scales and crusts are not present. Vestibule is of medium depth. Labial Frenulum are of the medium type (4 mm) from the top of papilla.

Jugal mucosa are pale pink, without pathologic elements. Gingival mucosa with the same color pale pink.

Dental inspection

Orthognatic occlusion

Dental formula

Percussion of teeth

Longitudinal or transverse moderate tooth is followed by a muffled sound, matte characteristic sign of teeth periodontal disease. Percussion in the axis are painless.

Complimentary exam

X-ray which not shows changes.

IV. Diagnosis

Based on complaints of patient's history and examination subjective and objective of disease is diagnosed by: Chronic deep caries tooth 36

Local:

Removal of soft deposits from the mouth by using scaling, plaque removal using the professional cleaning.

Rainfall irrigation with antiseptic solutions (chlorhexidine 0.06%, hexoral).

Professional cleaning

Anesthesia with ubistezin 4% 1.7ml

Initial look of tooth after isolation

Fig. II. 2.1.9 before treatment t.36

Preparing of the cavity

Medicamentos cleaning with chlorhexidine 0.06%

Afeter preparation and medicamentos cleaning

Fig. II. 2.1.10 After preparation

Indirect capping with hydroxide of calcium Cal LC photo

Baseliner SDR

Fig. II. 2.1.11 After application of SDR

Etching, and bonding Gbond GC and light cure

Obturation with composite Gradia Direct, polishing and final view

Fig. II. 2.1.12 After obturation of tooth 36

Patient education for correct cleaning and maintaining oral hygiene.

Conclusion

Evaluation and presentation of deep caries is only possible after clinical examination, diagnosis and differential diagnosis and it is important for effective contemporary methods of treatment.

SDR™ allows the use of a simplified filling technique applied in increments of up to 4mm and capped with a universal composite at the occlusal surface. This is achieved with a reduction in the polymerization stress and a high depth of cure. To achieve this, a modulator has been built into the conventional monomer – this also allows SDR™ to be used with other conventional adhesives and composites.

The use SDR provides less microleakage, suggesting a better sealing tooth-restoration interface, thus providing a significant advantage over traditional composite resins.

SDR composites creates an easier , less time consuming way for restoring deep caries cavities with the outmost esthetical results.

Summery

Diploma thesis “DEEP CARIES AND SDR COMPOSITE” was done on the basis of clinical data collected at the department of therapeutic dentistry in stomatological clinic USMF “N.Testemitianu”.

The treatment was performed on 12 patients 8 (66.6 %) male and 4 (33.3 %) female. Secondary caries it was present in the class I by Black 9 cases (75 %), class II by Black 2 (16.6 %) and class III by Black 1 (8.3%).

To insure a successful treatment with the best prognosis, removal of soft and hard deposits sub gingival and supra gingival is necessary .we used scaling and for plaque removal we used brushing professional with paste ,,Polident’’.

After preparation of the caries cavity it was crucial to obtain aseptic environment, this was performed by using antiseptic solutions (chlorhexidine 0.06%, hexoral). Furthermore Calcium hydroxide light cure Cal LC was used in deep caries, and baseliner SDR.

Deep caries lesions possess a significant importance for the development of pulpal pathosis, so it was important to appreciate the remaining dentin thickness (RDT), and by doing that we could determine the proper treatment plan (indirect capping).

Filling of the caries cavity was performed using nano composite “Gardia direct” and G-eanial from GC, the properties of SDR composites are highly superior to conventional composites, it was easier to work with, less time consuming and thus patient friendly .

In our work, the treatment was aimed at protecting the pulp and preventing its complications during and after treatment. Patients were taken to the dispensary registration. In our work was important to: Keep the pulp vitality, The elimination of dentinal infection, Generation or remineralization of hard dental tissue, Applying restoration material with long term prognosis.

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