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https://doi.org/10.15644/asc49/3/7

Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled

Theodoros Klironomos ; Privatna ordinacija, Atena, Grčka
Aspasia Katsimpali ; Privatna ordinacija, Atena, Grčka
Gregory Polyzois ; Odjel za protetiku Stomatološkog fakulteta Atenskoga sveučilišta, Atena, Grčka

Puni tekst: hrvatski, pdf (190 KB) str. 242-253 preuzimanja: 235* citiraj
APA 6th Edition
Klironomos, T., Katsimpali, A. i Polyzois, G. (2015). Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled. Acta stomatologica Croatica, 49 (3), 242-253. https://doi.org/10.15644/asc49/3/7
MLA 8th Edition
Klironomos, Theodoros, et al. "Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled." Acta stomatologica Croatica, vol. 49, br. 3, 2015, str. 242-253. https://doi.org/10.15644/asc49/3/7. Citirano 26.09.2020.
Chicago 17th Edition
Klironomos, Theodoros, Aspasia Katsimpali i Gregory Polyzois. "Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled." Acta stomatologica Croatica 49, br. 3 (2015): 242-253. https://doi.org/10.15644/asc49/3/7
Harvard
Klironomos, T., Katsimpali, A., i Polyzois, G. (2015). 'Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled', Acta stomatologica Croatica, 49(3), str. 242-253. https://doi.org/10.15644/asc49/3/7
Vancouver
Klironomos T, Katsimpali A, Polyzois G. Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled. Acta stomatologica Croatica [Internet]. 2015 [pristupljeno 26.09.2020.];49(3):242-253. https://doi.org/10.15644/asc49/3/7
IEEE
T. Klironomos, A. Katsimpali i G. Polyzois, "Učinak mikrovalne dezinfekcije na polimernu bazu proteze, ljepilo i zube: osnovni pregled", Acta stomatologica Croatica, vol.49, br. 3, str. 242-253, 2015. [Online]. https://doi.org/10.15644/asc49/3/7
Puni tekst: engleski, pdf (190 KB) str. 242-253 preuzimanja: 198* citiraj
APA 6th Edition
Klironomos, T., Katsimpali, A. i Polyzois, G. (2015). The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview. Acta stomatologica Croatica, 49 (3), 242-253. https://doi.org/10.15644/asc49/3/7
MLA 8th Edition
Klironomos, Theodoros, et al. "The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview." Acta stomatologica Croatica, vol. 49, br. 3, 2015, str. 242-253. https://doi.org/10.15644/asc49/3/7. Citirano 26.09.2020.
Chicago 17th Edition
Klironomos, Theodoros, Aspasia Katsimpali i Gregory Polyzois. "The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview." Acta stomatologica Croatica 49, br. 3 (2015): 242-253. https://doi.org/10.15644/asc49/3/7
Harvard
Klironomos, T., Katsimpali, A., i Polyzois, G. (2015). 'The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview', Acta stomatologica Croatica, 49(3), str. 242-253. https://doi.org/10.15644/asc49/3/7
Vancouver
Klironomos T, Katsimpali A, Polyzois G. The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview. Acta stomatologica Croatica [Internet]. 2015 [pristupljeno 26.09.2020.];49(3):242-253. https://doi.org/10.15644/asc49/3/7
IEEE
T. Klironomos, A. Katsimpali i G. Polyzois, "The Effect of Microwave Disinfection on Denture Base Polymers, Liners and Teeth: A Basic Overview", Acta stomatologica Croatica, vol.49, br. 3, str. 242-253, 2015. [Online]. https://doi.org/10.15644/asc49/3/7

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Sažetak
Svrha ovoga članka bila je sažeti trenutačno znanje o učincima mikrovalne dezinfekcije na svojstva materijala za izradu proteza. Kontrola križne infekcije u dentalnoj medicini itekako je važna u svakodnevnoj kliničkoj praksi jer su u porastu razne infektivne bolesti poput hepatitisa B i C te AIDS-a (side), a metode dezinfekcije su mnogobrojne. Najraširenija u svakodnevnoj praksi jest ona kemijska, premda istraživanja upućuju na to da se tako mijenjaju fizikalna i mehanička svojstva akrilatnih smola te omogućuje rast i proliferacija određenih bakterija. A mikrovalna metoda pokazala se kao jednostavna za uporabu, jeftina je i u postupku se ne upotrebljavaju kemikalije. Pitanje koje se postavilo glasi: utječe li podvrgavanje mikrovalovima na svojstva materijala od kojih se izrađuju proteze. Mikrovalovi različito djeluju na bazu proteze, ljepilo i zube. Istraživanja su pokazala da je mikrovalna dezinfekcija sigurna alternativa za bazu proteze i podložnu masu – u usporedbi s kemijskom metodom – ako se postupak obavlja u suhom okružju, ali mogla bi uzrokovati klinički veće dimenzijske promjene kad bi se iradijacija obavljala u vlažnim uvjetima. Nema ni klinički značajnih učinaka slabljenja savojnih svojstava, zatezne čvrstoće i tvrdoće akrilatne smole proteze, ni integriteta sredstva za vezivanje i njegove čvrstoće na savijanje, poroznosti i tvrdoće. Učinci dezinfekcije mikrovalovima na čvrstoću zuba u protezi i na vezu zubi – proteza i
dalje su sporni, pa još nema definitivnog zaključka.

Ključne riječi
mikrovalovi; dezinfekcija; infekcija, bolnička; akrilne smole; sintetičke smole; fizikalni fenomeni

Hrčak ID: 145318

URI
https://hrcak.srce.hr/145318

▼ Article Information



Introduction

Cross-infection control in dentistry has become a major issue since the recent increase in some infectious diseases such as hepatitis B, C and AIDS (1) occurred. By dealing with removable prosthodontics the dentist, the dental personnel and the patients are constantly facing the risk of self-inoculation and transmission of microorganisms since the oral surgery environment usually includes a mixture of blood and saliva which contaminates a great number of instruments and items that are not easily disinfected nor sterilized such as prostheses, impressions, stone casts. Although ADA has published guidelines in order to prevent the transmission of infectious diseases in dental offices, many have failed (2). A number of studies have presented numerous methods to avoid cross infection in the dental practice.

Chemical disinfection was the recommended method to be used after the removal and before the insertion of the prosthesis in the patient’s mouth. The disinfectant solutions used in the past were chlorine dioxide, sodium hypochlorite, 4% chlorhexidine and glutaraldehyde (3-5). However, studies on the effects of chemical disinfection on the physical-mechanical properties of acrylic resins came to the conclusion that these were altered (6, 7). For example, dentures were presented with staining, brownish discoloration of the teeth and the acrylic denture base and patients reported a number of oral tissue reactions (1, 8). The major disadvantage of chlorine dioxide is that it was rejected by the patients because of its offensive odor (9), its bleaching action over the denture resin base and its corrosive effect on the framework (6, 10). In addition, glutaraldehyde and sodium hypochlorite presented high or medium cytotoxicity risk (11). Furthermore, studies have demonstrated that such solutions can provide a suitable environment for growth of certain bacteria (12). In conclusion, denture soaking chemical methods are considered to be time consuming or inappropriate for chairside procedures (13).

Therefore, in order to overcome the problems occurring with chemical disinfection, microwaves were suggested as a low-cost, quick, efficient, and chemical free alternative. Microwaves are a type of electromagnetic energy with wavelengths close in frequency to television transmissions and aircraft radar. It is very important to note that microwave heating is an energy conversion and differs greatly from heating in a conventional oven (1). The exact mechanism of destruction of the microwaves has yet to be fully understood. Some studies claim that the irradiation of the microorganisms is directly of thermal character, (14) while others claim that non thermal effects may play a significant role (15, 16).

It is shown that microwaving dentures is equal to or more effective than sterilizing them in a 0.02% solution of sodium hypochlorite for 8h (17). Since the main goal of microwave disinfection is to deactivate potentially pathogenic microorganisms, some studies reported that dentures microwaved in water were more effectively disinfected than dentures irradiated in dry conditions (18). Some researchers recommend microwave disinfection in order to prevent or even treat denture stomatitis, since it was shown that microwave irradiation successfully eradicates Candida species from the infected dentures (19-21).

However, microwaving may negatively affect denture resins, liners or teeth due to the material heating after irradiation. The water starts to boil after approximately 1 minute and 30 seconds and remains at this temperature until the end of the pre-set disinfection time, (14) a phenomenon that may have negative effects on denture related materials’ physical-mechanical properties. In order to moderate the cumulative distortion produced by the excessive heat, some researchers even suggested the combination of tablets containing alkaline peroxide and enzymes with microwave irradiation, thus achieving faster disinfection and less heat compared to the use of microwaves alone (22).

The aim of this paper was to overview the current scientific knowledge concerning the effect of microwave disinfection on denture related material properties.

Denture Bases

A denture base is a part of a denture which rests on the foundation area. The artificial teeth are fixed on its upper surface (23).

It is used to replace the missing alveolar ridge both in bulk and appearance. Furthermore, it is the part of a denture where the prosthetic teeth are attached and provide bracing and retention for the denture. It facilitates the transfer of occlusal forces to the abutment teeth and when the denture is tissue supported to the foundation area (23).

Dimensional stability

The dimensional stability of a denture is the degree to which the material used for its fabrication retains its primary dimensions. The clinical significance of this parameter is very crucial, as it affects the fit of a denture, making it intolerable to the tissue and as a result to the patient. Great dimensional changes can also add an extra pressure to the mucosa which might traumatize the underlying bone and increase its resorption.

Microwave disinfection’s effects on the dimensional stability of acrylic resins is widely examined in the literature since it could influence the fit, retention and stability of complete dentures (24).

Seo et al. (24) submitted denture bases to microwave disinfection at 650 W for 6 min (once per day for 7 days) and concluded that this procedure led to denture bases’ shrinkage, but the clinical relevance of these findings was not assessed. Webb et al. (17) and Pavan et al. (3) also demonstrated that denture bases are likely to undergo damaging dimensional alternations when disinfected by microwave irradiation. The irradiation parameters were 604 W for 10 minutes.

Sartori et al., (25) submitted denture bases to microwave disinfection (690W for 6 min in 500 mL of distilled water) and compared them to bases that had previously been chemically disinfected with a 100 ppm active chloride solution. They stated that bases disinfected with microwaves after a period of time did not fit to their casts, unlike bases immersed in chloride solutions. In addition, Goncalves et al., reported that microwave irradiation (650 W for 6 min in 200 mL of water for 7 times) revealed significant differences in the linear dimension of denture bases (26). Senna et al. observed significant linear distortion when the dentures were submitted to 36 cycles of microwave irradiation at 900 W for 3 min in wet environment. Nevertheless, they reported that 6 cycles of microwave irradiation at 450 or 630 W for 3 min caused no significant alternations (27). Wagner and Pikpo also observed important dimensional changes of approximately 3% when dentures were exposed twice to either 420 or 700 W of microwave irradiation in wet environment for 3 min (28). Sartori et al., (29) also investigated the effect of microwave disinfection (two cycles at 690 W for 6 min) on the tridimensional stability of denture bases and showed that this procedure generated a progressive increase in distortion after 14 days as a result.

On the contrary to the aforementioned, Consani et al. found no significant dimensional changes when they submitted dentures to microwave disinfection (650 W / 3 min) (30). Polyzois et al. (7) reported that 3 and 15 min of microwave exposure at 500 W could cause dimensional changes of no clinical importance (<0.03%) on the dentures. Rohler and Bulard (31) asserted that both wet and dry dentures’ exposal to microwave disinfection at 720 W for 16 minutes, showed no dimensional changes. Webb et al. (17) came to the same conclusion but only when dentures were irradiated with reduced exposures (331 W for 6 min).

Burns et al. (32) showed that specimens made from three different acrylic resins had no alternations on their dimensional stability after 15 min at 650 W of microwave irradiation. Fleck et al. investigated the effect of two microwave disinfection protocols (690 W / 6 min) and (345 W / 6 min) on the dimensional stability of acrylic resin denture bases. The procedure for both disinfection protocol groups was performed 3 times with a 7-day interval. They found that the first protocol had detrimental effects on the dimensional stability of denture bases, but they also suggested that 345 W for 6 min had no significant effects on them (33). Polychronakis et al. irradiated dentures daily for a week in both dry and wet conditions for 6 minutes at 650 W and concluded that the dimensional changes observed when the disinfection took place in dry conditions were of no clinical significance (34).

The controversy in the aforementioned results may be attributed to the difference in the disinfection time, power of the microwave oven, type of the materials and methods used to measure distortion (25). For example, denture resin materials have different behavior if irradiation takes place in dry or wet conditions. The immersion in water was adopted because it was believed that it increases the effectiveness of the disinfection (19). However, the water starts to boil after 90 seconds of irradiation (19), which could lead to an increase in temperature beyond the acrylic resin’s glass transition temperature and thus it would become more flexible (35). This may facilitate the warping of denture bases, caused by the release of stresses stored within the material during fabrication (36, 37). Furthermore, it is highly possible that the higher temperature of the water may enhance the dispersion of the remaining residual monomer molecules (38, 39) to the active sites of the polymer chain (40). Consequently, further polymerization may lead to shrinkage of the denture bases.

Basso et al. investigated the effects of microwave disinfection on the occlusal vertical dimension changes of complete dentures. The researchers submitted maxillary compete dentures to microwave irradiation at 650 W for 3 min. When the specimen was irradiated once a week for 4 weeks, no significant differences were observed in the occlusal vertical dimension. Nevertheless, the specimens submitted to microwave disinfection 4 times a week for 4 weeks underwent unacceptable distortion. They suggested that when dentures are exposed to many cycles of microwave irradiation, the differences in occlusal vertical dimension are caused by the release of the inherent stress established during fabrication (41).

Flexural strength

Flexural strength is the simultaneous measurement of tensile, shear bond and compressive strengths (42). It describes the loading that occurs on the denture during mastication. Clinically, diminished flexural strength could lead to dentures more prone to fracturing.

Polyzois et al. (7) suggested that the changes in flexural strength after microwave disinfection (500 W / 3 or 15 min) of denture base resins in the dry state were of no clinical importance. Consani et al. (43, 44) indicated that the method of microwave disinfection (5 cycles at 650 W for 3 min in water) had no important discrepancies in the flexural strength between disinfected and non-disinfected specimens. Ribeiro et al. in their research (650 W / 1-5 min / 2 cycles / immersed in water) came to the same conclusion (45). Konchada et al. also found no alternations in flexural strength when they irradiated dentures at 650 W for 5 min, while immersed in water (42). Senna et al. observed no significant changes in flexural strength after 6 cycles of microwave irradiation at 450 or 630 W for 3 min, even though the elastic modulus decreased after 36 irradiation cycles (27).

On the other hand, Hamouda and Ahmed demonstrated that both 5 and 15 minutes of microwave disinfection at 750 W, either in dry conditions, or immersed in water produced a reduction of the flexural properties of denture base acrylic resins and concluded that this method is not acceptable for dentures (1).

Impact strength

Impact strength is a measure of energy received by the material when it experiences sudden fracture (42). A denture with high impact strength is more resilient to fracturing. Thus it is highly favored for a disinfection procedure not to diminish dentures’ impact strength values.

Seo et al. demonstrated that the impact strength of denture bases disinfected with microwaves (650 W / 6 min) daily for a period of seven days showed no differences compared to the control group (46). Konchada et al. also concluded that microwave disinfection at 650 W for 5 min did not affect dentures’ impact strength (42). Senna et al. reported that 36 cycles of microwave irradiation at 630 or 900 W for 3 min caused no significant changes to dentures’ impact strength (27).

Conversely, Hamouda and Ahmed claimed that either immersed or non-immersed in water, microwave disinfection (750 W / 5 or 15 min) is detrimental for their impact strength - along with other properties (1).

Hardness

Hardness is directly connected with the integrity of a material and its resilience to decay by thermal, chemical or mechanical action (27). In clinical situations, hardness represents dentures’ resilience to abrasion over time. A disinfection procedure which decreases dentures’ hardness is unacceptable for clinical use because it makes them prone to wear.

Ribeiro et al. showed that the disinfection control protocol (650 W / 1-5 min / 2 cycles / immersed in water) had no detrimental effects on dentures’ hardness (45). Dixon et al. noticed an increase in hardness, but they considered this increment of no clinical significance (47). Polyzois et al. demonstrated that the hardness of a denture base resin remained unaffected during microwave disinfection (500 W / 3 and 15 min) in the dry state (7). Sartori et al. also found that microwave disinfection had no effect of clinical significance on their hardness compared to the traditional disinfection procedure, but decreased after 14 days (29). Still, they concluded that the traditional immersion in chloride solution is a safer procedure than the conventional microwave protocol (690 W for 6 min) with regard to surface hardness of dentures (29). Konchada et al. reported that microwave irradiation at 650 W for 5 min in wet conditions did not change the hardness of the dentures disinfected (42).

Consani et al. reported that microwave disinfection (650 W / 3 min / 1 cycle / in wet conditions) (43) and (650 W / 3 min / 5 cycles / in wet conditions) (44) decreased the hardness of the denture resin tested.

On the other hand, Senna et al. demonstrated that in fact microwave disinfection increases the dentures hardness after 36 irradiation cycles at 630 or 900 W / 3 min (27).

Hard and Resilient Denture Liners

Bond strength

Loss of adhesion between denture bases and liners is a common clinical failure examined in previous studies (48-51). A strong bond is necessary in order to prevent abruption of the liner, staining and retention of bacteria (52). In addition, the quality of the bonding increases the flexural strength of the liner (50). Braden has shown that the temperature of the water has an important effect on the diffusion of water into acrylic resins (51). As a result, the heat generated by microwave disinfection might cause an increase in the water sorption rate which will decrease the bond between the denture base and the liner (48) since the absorbed water acts as a plasticizer (53).

Machado et al. reported that seven cycles of microwave disinfection at 650 W for 6 min while immersed in water had no detrimental effects on the bond strength values of two hard chair-side (54) and two resilient liners (55).

Flexural Strength

The reduction of liners’ flexural strength during microwave disinfection could make the material more brittle and thus more prone to crack propagation and fracture. The residual monomer of denture liners’ resin might adversely affect their flexural strength by a plasticizing effect which diminishes interchain forces (56). In this context, microwave irradiation may escalate the degree of conversion of auto-polymerized resins, thus enhancing their flexural strength. On the other hand, microwave disinfection in wet conditions could lead to the reduction of liners’ flexural strength which might be related to the plasticizing effect of absorbed water molecules (53, 56). According to that, the residual monomer that might leach out while immersed in water, has a lesser plasticizing effect than the received water molecules, a phenomenon that leads to diminished flexural strength.

Ribeiro et al. suggested that two cycles of microwave disinfection (650 W) on four different hard liners after different exposure times (1-5 min) had no detrimental effects on their flexural strength (45). Vergani et al. (57) examined the flexural strength of four hard denture liners that were irradiated for 3, 4 and 5 minutes at 500, 550 and 650W respectively and concluded that the flexural strength of certain liners could possibly be optimized by the proper power/time combination with microwave post-polymerization irradiation, thus resulting in the improvement of the longevity of the relined dentures.

Pavarina et al. (6) demonstrated that microwave disinfection at 650 W for 6 min (2-7 cycles) increased the flexural strength of five hard chair-side reline materials. Patil et al. also investigated the effects of microwave disinfection on two resilient liners and concluded that 650 W for 5 min increased their flexural strength (58).

Porosity

The ideal surface of the liners should be smooth. However, porosity is a common clinical flaw that often occurs and leads to staining, calculus deposition and accumulation of microorganisms (59, 60). Even after the relined denture has been cleaned, there is a great chance that numerous microorganisms remain (61). Porosity through microwave disinfection may occur from the vaporization of the unreacted monomer due to the high temperatures that these materials are exposed (62).

Novais et al. examined the occurrence of porosity after microwave disinfection (650 W / 6 min / 7 cycles) in five hard liners and came to mixed results, since some liners experienced an increase in their porosity, others presented a decrease and one material remained stable (62).

Dimensional stability

Denture liners are commonly used in order to improve the clinical fit of complete dentures (18). However, during microwave disinfection liners are exposed to very high temperatures even beyond the glass transition of the polymers, resulting in their distortion (18). In addition, the high temperature affects the free monomer and promotes further polymerization and thereby extra dimensional changes (63).

Seo et al. examined the dimensional stability of four hard liners after microwave disinfection (650 W / 6 min / 7 cycles) and suggested that the procedure produced increased shrinkage on the specimens tested (24).

Basso et al. (18) evaluated the effect of microwave disinfection (650 W / 3 min / 1-5 cycles) on hard chair-side reline resins and came to mixed observations. Some of the liners presented shrinkage, but in others no wrapping was observed. Goncalves et al. also examined the dimensional stability of four hard chair-side liners after microwave disinfection (650 W / 6 min / 2 or 7 cycles) and concluded that two of them shrank and the other two remained stable (26).

Hardness

Hardness is considered a very important physical property of the liners used in removable prosthodontics. When hardness increases by time, liners lose their elasticity, an implication that leads to excessive occlusal forces to the underline mucosa, pain, soft tissue irritation and subsequently to bone resorption and denture misfit.

Dixon et al. showed that microwave disinfection produced marginal and not clinically significant effects on the hardness of two resilient liners when the irradiation took place in wet conditions (47). Ribeiro et al. also investigated the effect of microwave irradiation (650 W / 1-5 min / 2 cycles) on the hardness of four hard liners after different exposure times, and found no significant discrepancies compared to the control group (45). Machado et al. submitted two resilient liners to microwave disinfection (650 W / 6 min / 7 cycles) while the specimens were immersed in 200 mL of water and reported that the hardness of the liners was not adversely affected by microwave irradiation (55). Pavan et al. also suggested that two cycles of microwave disinfection (500 W / 3 min) did not affect the hardness values on the long-term resilient denture liners that were examined (64).

Denture teeth

Denture teeth are made of either porcelain or more prevalently by polymers. Polymer teeth are classified based on their composition and system of polymerization to conventional acrylic resin teeth and IPN (Interpenetrating Polymer Network) teeth. Conventional acrylic resin teeth have a homogeneity in their configuration and a polymer network of one resin type. On the other hand, IPN teeth chemically consist of two polymer networks mechanically tangled together. These networks are highly cross-linked and their polymerization creates strong chemical bonds (23).

The polymer teeth retention to the denture base is mainly achieved by micromechanical interlocking between the denture’s polymer and the polymer network of the prosthetic teeth (23).

Hardness

Hardness is one of the most essential physical properties of resin denture teeth examined in the literature. It is used for the assessment of prosthetic teeth wear resistance as they operate to maintain the originally established vertical dimension and masticatory activity (65-68).

Campanha et al. showed that the hardness of acrylic resin denture teeth presented no significant changes if microwave disinfection (3 cycles) is used at 650 W for 6 min in a wet environment for 90 days (67).

However, Vasconelos et al. reported that 3 cycles of microwave disinfection at 1300 W for 3 min significantly decreased denture teeth hardness, compared to the traditional glutaraldehyde and hypochloride disinfecting solutions (69). Campanha et al. (70) also suggested that seven cycles of microwave irradiation (650 W / 6 min) decreased the hardness of all acrylic resin teeth tested.

Bond strength

The unexpected detachment of teeth from dentures is a very important issue that compromises integrity and clinical service ability of complete dentures. Crack propagation, residual wax contamination of teeth and excessive stress were to blame for teeth debonding in the past (71, 72). In order to consider microwave irradiation as a reliable alternative for denture disinfection, it is crucial that it does not adversely affect the teeth/denture bond strength, consequently leading to teeth debonding after several disinfection cycles. Thus, the possible weakening effects of microwave disinfection on the teeth/denture bond strength is examined thoroughly in the literature as it is an issue of great clinical significance.

Campanha et al. investigated the effect of microwave irradiation (650 W / 3 min) on the bond between teeth and denture bases and concluded that this procedure might lead to important decrease of the bond strength values, regardless of the ridge laps treatments which may have been used (73). They also submitted acrylic specimens treated with different techniques to microwave irradiation (650 W / 3 min) while immersed in water and compared to the control group; and the irradiated specimens presented decreased teeth/resin bond strength values (74). However, in their latest study, Campanha et al. disputed the negative effects of microwave disinfection (650 W / 3 min) on the teeth/base bond strength, suggesting that 5 irradiation cycles not only do not decrease, but also increase the bond values (75).

From this overview it could be concluded that there are still reservations and lasting questions remaining unanswered. For instance, there is no established protocol for the use of microwave irradiation that ensures dentures’ disinfection by causing no implications of clinical significance on their physical-mechanical properties. Also, the exposure time and power used, seems to have been randomly selected. There is a wide range of parameters used, from 350 to 1400 W and from 1 to 20 min (76). Furthermore, the optimal irradiation frequency and the mid- and long-term effects of periodical microwave disinfection on dentures remain unknown. Thus, more studies should be conducted investigating the effects caused by microwave irradiation on denture related materials in the mid- and long-term, providing a reliable disinfection protocol and examining more physical-mechanical properties, e.g. color stability, viscoelastic properties, residual monomer, etc.

Discussion

Chemical disinfectants were the main method for preventing cross-contamination in the past. Although, their usage produced significant disadvantages such as denture staining and intra-oral tissue reactions (8). Other problems presented in the literature were a characteristic offensive odor after the use of sodium chloride, brownish discoloration of dentures and tongue (1), alterations of acrylic resins properties (7) and penetration of certain chemical disinfectants’ components in the material after the disinfection procedure (67).

On the other hand, microwave disinfection is a simple, quick and easy to use alternative. It does not produce brownish discoloration on dentures and oral tissues, nor has an unpleasant odor. It also disinfects dentures effectively and does not have an expiration date. Nevertheless, it cannot disinfect dentures with metal parts and its daily use is still debatable (76).

Considering the data from the aforementioned literature, it can be concluded that microwave irradiation is a recommended alternative for the disinfection of dentures and liners if the procedure is carried out in dry conditions for a maximum of 3 disinfection cycles. Furthermore, the optimum disinfection parameters in order to achieve best disinfection results with minimum adverse influence onto dental materials’ physical-mechanical properties are 650 W for 3 minutes.

Conclusions

  • Microwave disinfection (650 W / 3 min / 3 cycles) is a safe alternative for the disinfection of denture bases and liners compared to the chemical one when the procedure is carried out in dry conditions, but could possibly cause dimensional changes of clinical significance when the irradiation takes place in wet environment. More than 3 cycles of microwave disinfection in these settings could adversely affect the physical-mechanical properties of denture base resins, liners or teeth.

  • Microwave irradiation (650 W / 3 min) seems to have no detrimental effects of clinical importance on the flexural properties, impact strength and hardness of denture resins and the bond, flexural strength, porosity and hardness of denture liners.

  • The effects of microwave disinfection on the hardness of denture teeth and teeth/denture bond strength are still controversial and no safe conclusions can be drawn.

References

1 

Hamouda IM, Ahmed SA. Effect of microwave disinfection on mechanical properties of denture base acrylic resin. J Mech Behav Biomed Mater. 2010 Oct;3(7):480–7. DOI: http://dx.doi.org/10.1016/j.jmbbm.2010.05.002 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/20696412

2 

ADA Council on Scientific Affairs and ADA Council on Dental Practice. Infection control recommendations for the dental office and the dental laboratory. J Am Dent Assoc. 1996 May;127(5):672–80. DOI: http://dx.doi.org/10.14219/jada.archive.1996.0280 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/8642147

3 

Pavan S, Arioli JN, Dos Santos PH, Mollo FA. Effect of microwave treatments on dimensional accuracy of maxillary acrylic resin denture base. Braz Dent J. 2005;16(2):119–23. DOI: http://dx.doi.org/10.1590/S0103-64402005000200006 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/16475605

4 

Lin JJ, Cameron SM, Runyan DA, Craft DW. Disinfection of denture base acrylic resin. J Prosthet Dent. 1999 Feb;81(2):202–6. DOI: http://dx.doi.org/10.1016/S0022-3913(99)70249-0 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9922434

5 

Pavarina AC, Pizzolitto AC, Machado AL, Vergani CE, Giampaolo ET. An infection control protocol: effectiveness of immersion solutions to reduce the microbial growth on dental prostheses. J Oral Rehabil. 2003 May;30(5):532–6. DOI: http://dx.doi.org/10.1046/j.1365-2842.2003.01093.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/12752936

6 

Pavarina AC, Neppelenbroek KH, Guinesi AS, Vergani CE, Machado AL, Giampaolo ET. Effect of microwave disinfection on the flexural strength of hard chairside reline resins. J Dent. 2005 Oct;33(9):741–8. DOI: http://dx.doi.org/10.1016/j.jdent.2005.02.003 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/16199282

7 

Polyzois GL, Zissis AJ, Yannikakis SA. The effect of glutaraldehyde and microwave disinfection on some properties of acrylic denture resin. Int J Prosthodont. 1995 Mar-Apr;8(2):150–4. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/7575966

8 

Baysan A, Whiley R, Wright PS. Use of microwave energy to disinfect a long-term soft lining material contaminated with candida albicans or staphylococcus aureus. J Prosthet Dent. 1998 Apr;79(4):454–8. DOI: http://dx.doi.org/10.1016/S0022-3913(98)70161-1 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9576322

9 

Albrer DJ. Post-placement care of complete and removable partial dentures. Dent Clin North Am. 1979 Jan;23(1):143–51. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/215469

10 

Council of Dental Materials, Instruments, and Equipment. Denture cleansers. J Am Dent Assoc. 1983 Jan;106(1):77–9. DOI: http://dx.doi.org/10.14219/jada.archive.1983.0001 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/6574171

11 

Sagripanti JL, Bonifacino A. Cytotoxicity of liquid disinfectants. Surg Infect (Larchmt). 2000;1(1):3–14. DOI: http://dx.doi.org/10.1089/109629600321245 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/12594904

12 

DePaola LG, Minah GE. Isolation of pathogenic microorganisms from dentures and denture-soaking containers of myelosuppressed cancer patients. J Prosthet Dent. 1983 Jan;49(1):20–4. DOI: http://dx.doi.org/10.1016/0022-3913(83)90230-5 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/6571900

13 

Connor C. Cross-contamination control in prosthodontic practice. Int J Prosthodont. 1991 Jul-Aug;4(4):337–44. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/1811627

14 

Yeo CB, Watson IA, Stewart-Tull DE. Heat transfer analysis of staphylococcus aureus on stainless steel with microwave radiation. J Appl Microbiol. 1999 Sep;87(3):396–401. DOI: http://dx.doi.org/10.1046/j.1365-2672.1999.00832.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/10540242

15 

Culkin KA, Fung DYC. Destruction of Escherichia coli and salmonella typhimurium in microwaved cooked soups. J Milk Food Technol. 1975;38:8–15.

16 

Rohrer MD, Terry MA, Bulard RA. Microwave sterilization of hydrophilic contact lenses. Am J Ophthalmol. 1986 Jan 15;101(1):49–57. DOI: http://dx.doi.org/10.1016/0002-9394(86)90464-2 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/3942177

17 

Webb BC, Thomas CJ, Harty DW, Willcox MD. Effectiveness of two methods of denture sterilization. J Oral Rehabil. 1998 Jun;25(6):416–23. DOI: http://dx.doi.org/10.1046/j.1365-2842.1998.00266.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9687113

18 

Basso MF, Giampaolo ET, Vergani CE, Machado AL, Pavarina AC, Ribeiro RC. Influence of microwave disinfection on the dimensional stability of denture reline polymers. J Prosthodont. 2010 Jul;19(5):364–8. DOI: http://dx.doi.org/10.1111/j.1532-849X.2010.00583.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/20345741

19 

Neppelenbrock KH, Pavarina AC, Spolidorio DM, Vergani CE, Mima EO, Machado AL. Effectiveness of microwave sterilization on three hard chairside reline resins. Int J Prosthodont. 2003 Nov-Dec;16(6):616–20. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/14714840

20 

Silva M, Consani R, Mesquita M, Macedo AP, Takahashi J. Microwave irradiation as an alternative method for disinfection of denture base acrylic resins. Minerva Stomatol. 2013 Jan-Feb;62(1-2):23–9. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/23422681

21 

Mima EG, Pavarina AC, Neppelenbroek KH, Vergani CE, Machado AL. Effect of different exposure times on microwave irradiation on the disinfection of a hard chairside reline resin. J Prosthodont. 2008 Jun;17(4):312–7. DOI: http://dx.doi.org/10.1111/j.1532-849X.2007.00277.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/18086140

22 

Senna PM, Sotto-Maior BS, Da Silva WJ, Del Bel Cury AA. Adding denture cleanser to microwave disinfection regimen to reduce the irradiation time and the exposure of dentures to high tempertures. Gerodontology. 2013 Mar;30(1):26–31. DOI: http://dx.doi.org/10.1111/j.1741-2358.2012.00641.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/22420329

23 

Demetriou P, Zisis A, Karkazis I, Polyzois G, Staurakis G. Dental materials for the construction of complete dentures. In: Pleponisel, MI – editor. Removable Prosthodontics: Complete Dentures. 4th ed. Athens: MI Bonisel MI; 2001. p. 115-42.

24 

Seo RS, Vergani CE, Pavarina AC, Compagnoni MA, Machado AL. Influence of microwave disinfection on the dimensional stability of intact and relined acrylic resin denture bases. J Prosthet Dent. 2007 Sep;98(3):216–23. DOI: http://dx.doi.org/10.1016/S0022-3913(07)60058-4 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/17854623

25 

Sartori EA, Schmidt CB, Walber LF, Shinkai RS. Effect of microwave disinfection on denture base adaptation and resin surface roughness. Braz Dent J. 2006;17(3):195–200. DOI: http://dx.doi.org/10.1590/S0103-64402006000300004 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/17262124

26 

Goncalves AR, Machado AL, Giampaolo ET, Pavarina AC, Vergani CE. Linear dimensional changes of denture base and hard chair-side reline resins after disinfection. J Appl Polym Sci. 2006 Oct;102(2):1821–6. DOI: http://dx.doi.org/10.1002/app.24052

27 

Senna PM, Da Silva WJ, Faot F, Del Bel Cury AA. Microwave disinfection: cumulative effect of different power levels on physical properties of denture base resins. J Prosthodont. 2011 Dec;20(8):606–12. DOI: http://dx.doi.org/10.1111/j.1532-849X.2011.00770.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/21980952

28 

Wagner DA, Pikpo JP. The effect of repeated microwave irradiation on the dimensional stability of a specific acrylic denture resin. J Prosthodont. 2015 Jan;24(1):25–31. DOI: http://dx.doi.org/10.1111/jopr.12203 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/25082075

29 

Sartori EA, Schmidt CB, Mota ED, Hirakata LM, Shinkai RS. Cumulative effect of disinfection procedures on microhardness and tridimensional stability of a poly(methyl methacrylate) denture base resin. J Biomed Mater Res B Appl Biomater. 2008 Aug;86(2):360–4. DOI: http://dx.doi.org/10.1002/jbm.b.31027 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/18161805

30 

Consani R, Mesquita M, Nobilo M, Henriques G. Influence of simulated microwave disinfection on complete denture base adaptation using different flask closure methods. J Prosthet Dent. 2007 Mar;97(3):173–8. DOI: http://dx.doi.org/10.1016/j.prosdent.2007.01.006 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/17394916

31 

Rohrer MD, Bulard RA. Microwave sterilization. J Am Dent Assoc. 1985 Feb;110(2):194–8. DOI: http://dx.doi.org/10.14219/jada.archive.1985.0250 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/3884686

32 

Burns DR, Kazanoglu A, Moon PC, Gunsolley JC. Dimensional stability of acrylic resin materials after microwave sterilization. Int J Prosthodont. 1990 Sep-Oct;3(5):489–93. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/2088388

33 

Fleck G, Ferneda F, Ferreira da Silva DF, Mota EG, Shinkai RS. Effect of two microwave disinfection protocols in adaptation of poly (methyl methacrylate) denture bases. Minerva Stomatol. 2007 Mar;56(3):121–7. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/17327816

34 

Polychronakis N, Yannikakis S, Zissis A. The effect of repeated microwaving disinfection on the dimensional stability of acrylic dentures. Acta Stomatol Croat. 2014 Dec;48(4):245–330. DOI: http://dx.doi.org/10.15644/asc48/4/5

35 

Ruyter IE, Svendsen SA. Flexural properties of denture base polymers. J Prosthet Dent. 1980 Jan;43(1):95–104. DOI: http://dx.doi.org/10.1016/0022-3913(80)90362-5 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/6927913

36 

Pow EH, Chow TW, Clark RK. Linear dimensional change of heat-cured acrylic resin complete dentures after reline and rebase. J Prosthet Dent. 1998 Aug;80(2):238–45. DOI: http://dx.doi.org/10.1016/S0022-3913(98)70117-9 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9710829

37 

Woelfel JB, Paffenbarger GC. Method of evaluating the clinical effect of warping a denture: report of a case. J Am Dent Assoc. 1959 Aug;59(2):250–60. DOI: http://dx.doi.org/10.14219/jada.archive.1959.0171 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/13672726

38 

Vallittu PK, Miettinen V, Alakuijala P. Residual monomer content and its release into water from denture teeth using a second heat cure. J Prosthet Dent. 1992 Apr;67(4):556–62. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/1507143

39 

Harrison A, Huggett R. Effect of the curring cycle on residual monomer levels of acrylic resin denture base polymers. J Dent. 1992 Dec;20(6):370–4. DOI: http://dx.doi.org/10.1016/0300-5712(92)90031-7 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/1452879

40 

Lamb DJ, Ellis B, Prietsley D. The effects of process variables on levels of residual monomer in autopolymerizing dental acrylic resin. J Dent. 1983 Mar;11(1):80–8. DOI: http://dx.doi.org/10.1016/0300-5712(83)90051-9 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/6573363

41 

Basso FM, Giampaolo ET, Machado AL, Pavarina AC, Vergani CE. Evaluation of the occlusion vertical dimension of complete dentures after microwave disinfection. Gerodontology. 2012 Jun;29(2):e815–21. DOI: http://dx.doi.org/10.1111/j.1741-2358.2011.00567.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/21981019

42 

Konchada J, Karthigeyan S, Asharaf Ali S, Venkateshwaran R, Amirisetty R, Dani A. Effect of simulated microwave disinfection on the mechanical properties of three different types of denture base resins. J Clin Diagn Res. 2013 Dec;7(12):3051–3. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/24551725

43 

Consani RL, Vieira EB, Mesquita MF. Effect of microwave disinfection on physical and mechanical properties of acrylic resins. Braz Dent J. 2008;19(4):348–53. DOI: http://dx.doi.org/10.1590/S0103-64402008000400011 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/19180326

44 

Consani RL, Azevedo DD, Mesquita MF, Mendes WB, Saquy PC. Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins. Braz Dent J. 2009;20(2):132–7. DOI: http://dx.doi.org/10.1590/S0103-64402009000200008 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/19738946

45 

Ribeiro DG, Pavarina AC, Machado AL, Giampaolo ET, Vergani CE. Flexural strength and hardness of reline and denture base acrylic resins after different exposure times of microwave disinfection. Quintessence Int. 2008 Nov;39(10):833–40. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/19093060

46 

Seo RS, Vergani CE, Giampaolo ET, Pavarina AC, Reis MS, Machado AL. Effect of disinfection by microwave irradiation on the strength of intact and relined denture bases and the water sorption and solubility of denture base and reline materials. J Appl Polym Sci. 2008 Jan;107(1):300–8. DOI: http://dx.doi.org/10.1002/app.27120

47 

Dixon DL, Breeding LC, Faler TA. Microwave disinfection of denture base materials colonized with Candida albicans. J Prosthet Dent. 1999 Feb;81(2):207–14. DOI: http://dx.doi.org/10.1016/S0022-3913(99)70250-7 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9922435

48 

Cucci AL, Vergani CE, Giampaolo ET. Water sorption, solubility and bond strength of two autopolymerizing acrylic resins and one heat polymerizing acrylic resin. J Prosthet Dent. 1998 Oct;80(4):434–8. DOI: http://dx.doi.org/10.1016/S0022-3913(98)70008-3 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9791790

49 

Takahashi Y, Chai J. Shear bond strength of denture reline polymers to denture base polymers. Int J Prosthodont. 2001 May-Jun;14(3):271–5. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/11484577

50 

Chai J, Takahashi Y, Kawaguchi M. The flexural strengths of denture base acrylic resins after relining with visible light activated material. Int J Prosthodont. 1998 Mar-Apr;11(2):121–4. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9709600

51 

Braden M. The absorption of water by acrylic resins and other materials. J Prosthet Dent. 1964 Mar;14(2):307–16. DOI: http://dx.doi.org/10.1016/0022-3913(64)90091-5

52 

Arena CA, Evans DB, Hilton TJ. A comparison of bond strengths among chairside hard reline materials. J Prosthet Dent. 1993 Aug;70(2):126–31. DOI: http://dx.doi.org/10.1016/0022-3913(93)90006-A PubMed: http://www.ncbi.nlm.nih.gov/pubmed/8371174

53 

Takahashi Y, Chai J, Kawagucci M. Effect of water sorption on the resistance to plastic deformation of a denture base material relined with four different denture reline materials. Int J Prosthodont. 1998 Jan-Feb;11(1):49–54. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9588991

54 

Machado AL, Breeding LC, Puckett AD. Effect of microwave disinfection procedures on torsional bond strengths of two hard chairside denture reline materials. J Prosthodont. 2006 Nov-Dec;15(6):337–44. DOI: http://dx.doi.org/10.1111/j.1532-849X.2006.00132.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/17096805

55 

Machado AL, Breeding LC, Puckett AD. Effect of microwave disinfection on the hardness and adhesion of two resilient liners. J Prosthet Dent. 2005 Aug;94(2):183–9. DOI: http://dx.doi.org/10.1016/j.prosdent.2005.04.017 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/16046971

56 

Dogan A, Bek B, Cevik NN, Usanmaz A. The effect of preparation conditions of acrylic denture base materials on the level of residual monomer, mechanical properties and water absorption. J Dent. 1995 Oct;23(5):313–8. DOI: http://dx.doi.org/10.1016/0300-5712(94)00002-W PubMed: http://www.ncbi.nlm.nih.gov/pubmed/7560378

57 

Vergani CE, Seo RS, Pavarina AC, Reis JM. Flexural strength of autopolymerizing denture reline resins with microwave postpolymerization treatment. J Prosthet Dent. 2005 Jun;93(6):577–83. DOI: http://dx.doi.org/10.1016/j.prosdent.2005.03.014 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/15942620

58 

Patil PS, Chowdhary R, Mandokar RB. Effect of microwave postpolymerization treatment on residual monomer content and the flexural strength of autopolymerizing reline resin. Indian J Dent Res. 2009 Jul-Sep;20(3):293–7. DOI: http://dx.doi.org/10.4103/0970-9290.57363 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/19884711

59 

Davenport JC. The oral distribution of candida in denture stomatitis. Br Dent J. 1970 Aug 18;129(4):151–6. DOI: http://dx.doi.org/10.1038/sj.bdj.4802540 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/5272473

60 

Budtz-Jorgensen E. The significance of candida albicans in denture stomatitis. Scand J Dent Res. 1974;82(2):151–90. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/4598186

61 

Verran J, Maryan CJ. Retention of Candida albicans on acrylic resin and silicone of different surface topography. J Prosthet Dent. 1997 May;77(5):535–9. DOI: http://dx.doi.org/10.1016/S0022-3913(97)70148-3 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/9151275

62 

Novais PM, Giampaolo ET, Vergani CE, Machado AL, Pavarina AC, Jorge JH. The occurrence of porosity in reline acrylic resins. Effect of microwave disinfection. Gerodontology. 2009 Mar;26(1):65–71. DOI: http://dx.doi.org/10.1111/j.1741-2358.2008.00251.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/18707626

63 

Urban VM, Machado AL, Oliveira RV, Vergani CE, Pavarina AC, Cass QB. Residual monomer of reline acrylic resins. Effect of water bath and microwave postpolymerization treatments. Dent Mater. 2007 Mar;23(3):363–8. DOI: http://dx.doi.org/10.1016/j.dental.2006.01.021 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/16620950

64 

Pavan S, Arioli J, Santos P, Nogueira S, Batista U. Effect of disinfection treatments on the hardness of soft denture liner materials. J Prosthodont. 2007 Mar-Apr;16(2):101–6. DOI: http://dx.doi.org/10.1111/j.1532-849X.2007.00162.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/17362419

65 

Mandikos MN, McGinvey GP, Davis E, Bush PJ, Carter JM. A comparison of the wear resistance and hardness of indirect composite resins. J Prosthet Dent. 2001 Apr;85(4):386–95. DOI: http://dx.doi.org/10.1067/mpr.2001.114267 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/11319537

66 

Kawano F, Ohguri T, Ichikawa T, Mizuno I, Hasegava A. Shock absorbality and hardness of commercially available denture teeth. Int J Prosthodont. 2002 May-Jun;15(3):243–7. PubMed: http://www.ncbi.nlm.nih.gov/pubmed/12066486

67 

Campanha NH, Pavarina AC, Vergani CE, Machado AL. Effect of microwave sterilization and water storage on the Vickers hardness of acrylic resin denture teeth. J Prosthet Dent. 2005 May;93(5):483–7. DOI: http://dx.doi.org/10.1016/j.prosdent.2005.02.016 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/15867760

68 

Kawano F, Ohguri T, Ichikawa T, Matsumoto N. Influence of thermal cycles in water on flexural strength of laboratory-processed composite resin. J Oral Rehabil. 2001 Aug;28(8):703–7. DOI: http://dx.doi.org/10.1046/j.1365-2842.2001.00724.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/11556949

69 

Vasconelos LR, Consani RL, Mesquita MF, Sinhoreti MC. Effect of chemical and microwave disinfection on the surface microhardness of acrylic resin denture teeth. J Prosthodont. 2013 Jun;22(4):298–303. DOI: http://dx.doi.org/10.1111/jopr.12009 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/23387984

70 

Campanha NH, Pavarina AC, Jorge JH, Vergani CE, Machado AL, Giampaolo ET. The effect of long-term disinfection procedures on hardness property of resin denture teeth. Gerodontology. 2012 Jun;29(2):e571–6. DOI: http://dx.doi.org/10.1111/j.1741-2358.2011.00520.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/21771050

71 

Darbar UR, Huggett R, Harrison A, Williams K. Finite element analysis of stress distribution at the tooth-denture base interface of acrylic resin teeth debonding from the denture base. J Prosthet Dent. 1995 Dec;74(6):591–4. DOI: http://dx.doi.org/10.1016/S0022-3913(05)80310-5 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/8778382

72 

Cunningham JL. Bond strength of denture teeth to acrylic bases. J Dent. 1993 Oct;21(5):274–80. DOI: http://dx.doi.org/10.1016/0300-5712(93)90106-Z PubMed: http://www.ncbi.nlm.nih.gov/pubmed/8227688

73 

Consani RL, Carmignani MR, Mesqyita MF, Correr-Sobringho L, Guiraldo RD. Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin. Gerodontology. 2010 Sep;27(3):236–42. DOI: http://dx.doi.org/10.1111/j.1741-2358.2009.00333.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/20545779

74 

Consani RL, Mesquita MF, Zampieri MH, Mendes WB, Consani S. Effect of the simulated disinfection by microwave energy on the impact strength of the tooth/acrylic resin adhesion. Open Dent J. 2008;2:13–7. DOI: http://dx.doi.org/10.2174/1874210600802010013 PubMed: http://www.ncbi.nlm.nih.gov/pubmed/19088877

75 

Consani RL, Soave T, Mesquita MF, Sinhoreti MC, Mendes WB, Guiraldo RD. Effect of repeated microwave disinfections on bonding of different commercial teeth to resin denture base. Gerodontology. 2012 Jun;29(2):e553–9. DOI: http://dx.doi.org/10.1111/j.1741-2358.2011.00516.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/21787371

76 

Brondani MA, Samim F, Feng H. A conventional microwave oven for denture cleaning: a critical review. Gerodontology. 2012 Jun;29(2):e6–15. DOI: http://dx.doi.org/10.1111/j.1741-2358.2010.00442.x PubMed: http://www.ncbi.nlm.nih.gov/pubmed/21083741


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