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. 2026 Jun 3;26:1181. doi: 10.1186/s12903-026-08791-9

Er: YAG laser debonding performance for cement-retained zirconia implant crowns

Xinyuan Zhang 1, Ziyang Yu 1, Qian Li 1, Xiaomin Wu 1, Chunlan Guo 1,✉, Haitao Dong 1,✉
PMCID: PMC13330164  PMID: 42237273

Abstract

Background

Erbium laser debonding methods have been increasingly applied in natural tooth restorations and are highly important for the repair and maintenance of cement-retained implant restorations. However, the debonding process is challenging, and research on its safety, efficacy, and influencing factors remains insufficient. Therefore, this study aimed to investigate the effects of different zirconia crowns and abutments on temperature increases and debonding time when using an Er: YAG laser to debond zirconia cement-retained implant crowns.

Methods

The different abutments and zirconia crowns were divided into four groups, the Ti-3Y, Ti-4Y/5Y, Zir-3Y, and Zir-4Y/5Y groups, with 8 zirconia crowns in each group. An Er: YAG laser was used to remove the crowns. The average and maximum temperature increases at three points, the abutment region (∆T1, ∆T1 MAX), middle of the implant (∆T2, ∆T2 MAX), and apical region of the implant (∆T3, ∆T3 MAX)) were measured using a thermocouple thermometer and calculations. The debonding time was also recorded. One crown from each group was randomly selected to evaluate the surface morphology with scanning electron microscopy (SEM). Data were analysed by one-way analysis of variance (ANOVA).

Results

All 32 zirconia crowns were successfully removed using the Er: YAG laser. With the same abutment, the ∆T1 MAX in the 3Y groups was lower than that in the 4Y/5Y groups. Compared with the 4Y/5Y groups, the 3Y groups required more time for the removal procedure (p < 0.05). With the same zirconia crown materials, the ∆T1 MAX in the Ti groups was lower than that in the Zir groups (p > 0.05), and the removal time in the Ti groups was shorter than that in the Zir groups (p > 0.05). SEM examinations did not reveal any signs of microcracks in the zirconia crowns.

Conclusion

The Er: YAG laser debonding method can be used to successfully remove cement-retained zirconia implant crowns, and the temperature increase and debonding time are affected by the type of zirconia crown but not the type of abutment.

Keywords: Er:YAG laser debonding, Cement-retained implant crowns, Abutment, Zirconia, Monolithic translucent multilayer zirconia

Background

Implant restoration is well accepted as a primary treatment option for the replacement of single or multiple missing teeth. Implant-supported restorations can be fixed by cementation or screw retention [1, 2]. Cement-retained implant restorations provide a design that reduces the complexity of components and laboratory procedures, offers benefits regarding occlusion, which is needed for axial loading, compensates for unfavourable angulations, and eliminates the unesthetic screw access hole (SAH), thus providing a better aesthetic appearance [3–6].

In the aesthetic zone, zirconia abutments are also considered the preferred choice for patients with thin gingival biotypes; compared with titanium abutments, zirconia abutments avoid the appearance of grey-bluish mucosa. Zirconia abutments combined with all-ceramic crowns can result in better aesthetic effects [7, 8]. However, glass ceramic crowns may exhibit grey or dark shades of titanium as the abutment colour, while veneered zirconia is vulnerable to chipping and delamination [9, 10]. To cover the titanium colour and achieve good aesthetic performance and long-term durability, a new generation of zirconia—monolithic translucent multilayer zirconia—is being applied in dentistry. These kinds of zirconia have layered structures with different yttrium contents and cubic phases and exhibit multilayer shading and translucency gradients to mimic the optical properties of natural teeth [11–13].

Implant restorations also need to be easy to maintain in the long term to achieve high survival rates [14]. In the case of problems such as soft tissue inflammation or abutment screw loosening or breaking, it is more difficult to retrieve the crown to treat cement-retained implant restorations than screw-retained implant restorations [15–17]. The traditional removal method involves the use of rotary instruments to section crowns into pieces, which may damage the underlying abutment such that the crown cannot be reused, causing inconvenience for both doctors and patients [18, 19].

The erbium-doped yttrium aluminium garnet (Er: YAG) laser can help solve this issue. In the last twenty years, the Er: YAG laser has been used to remove all-ceramic restorations, including veneers, crowns, and even cement-retained implant crowns [20–23]. The mechanism of Er: YAG laser debonding is that laser energy penetrates ceramics and is absorbed by the luting cement containing water molecules and residual monomers, causing cement degradation, reducing bond strength and enabling the removal of the restorations [24, 25].

Deeb JG et al. and Grzech-Leśniak K applied an Er: YAG laser to successfully remove glass ceramic crowns from titanium or zirconia abutments and reported that no microcracks or fractures were detected on the surface of either the crown or abutment [16, 26]. Elkharashi A et al. used an Er: YAG laser to retrieve zirconia crowns intact from zirconia abutments, and energy dispersive spectroscopy analyses revealed no visual or elemental composition changes in the crown or abutment [27]. The removed intact crowns could potentially be reused, which is highly important for the long-term maintenance of implant restorations.

Recent studies have investigated the feasibility and effectiveness of debonding implant restorations with Er: YAG lasers, but research on the Er: YAG laser debonding performance in the context of the new generation of zirconia, i.e., monolithic translucent multilayer zirconia, is limited. Research on the effects of different types of abutments and crowns on the duration and temperature changes of implants within simulated alveolar bone when debonded with the Er: YAG laser method is also relatively limited. Therefore, the purpose of this study was to investigate the Er: YAG laser debonding performance for monolithic translucent multilayer zirconia implant crowns, including comparisons of debonding efficiency and temperature safety, to guide clinical applications. The null hypotheses were as follows: (1) the type of zirconia crown does not affect the temperature increase or the debonding time, and (2) the type of abutment does not affect the temperature increase or the debonding time.

Materials and methods

Experimental model preparation

Four maxillary dentition models with upper right central incisors missing were designed digitally and 3D printed with resin (DM12-V2, Shining 3D, HangZhou, China) using a 3D printer for fabrication (ACCUFAB-DIS, Shining 3D, HangZhou, China). Four bone-level titanium implants (Nobel Active RP 4.3*11.5 mm, Nobel Biocare, Sweden) were implanted separately in the missing tooth areas. The four printed resin models were divided into 4 groups to receive different abutments and zirconia crowns (n = 8), as presented in Table 1.

Table 1.

General description about the types of abutments and zirconia crowns in each group

Groups Abutment (brand) Zirconia crown (brand)
Ti-3Y

Ti abutment

(esthetic Abutment CC RP, Nobel Biocare, Stockholm, Sweden)

3Y-TZP

(3 mol% yttria- tetragonal zirconia polycrystal);

(ST, Upcera Dental, Shenzhen, China)
Ti-4Y/5Y

Ti abutment

(esthetic abutment CC RP, Nobel Biocare, Stockholm, Sweden)

4Y/5Y-PSZ

(4 mol ~ 5 mol% yttria- partially stabilized zirconia);

(TT-GT, Upcera Dental, Shenzhen, China)
Zir-3Y

Ti-base-Zirconia abutment

Ti-base (universal base RP 1.5 mm, Nobel Biocare, Stockholm, Sweden);

Zirconia abutment (3Y-TZP) (Zenostar T, Wieland Dental, Pforzheim, Germany)

3Y-TZP

(3 mol% yttria- tetragonal zirconia polycrystal);

(ST, Upcera Dental, Shenzhen, China)
Zir-4Y/5Y

Ti-base-Zirconia abutment

Ti-base (universal base RP 1.5 mm, Nobel Biocare, Stockholm, Sweden);

Zirconia abutment (3Y-TZP) (Zenostar T, Wieland Dental, Pforzheim, Germany)

4Y/5Y-PSZ

(4 mol ~ 5 mol% yttria- partially stabilized zirconia);

(TT-GT, Upcera Dental, Shenzhen, China)
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In the Ti-3Y group, a titanium abutment (esthetic abutment CC RP) was screwed to the implant, and artificial gums were made. A digital scanner (TRIOS 3, version 21.3.2, 3Shape, Denmark) was used to scan the model, and an STL file was obtained. Eight 3Y-TZP crowns (ST) were designed using 3 Shape software (3 Shape 20.21.23.) and milled with a milling machine (K5, vhf camfacture, Ammerbuch, Germany) from a presintered zirconia block. The monolithic crown was then sintered (Programat S1 1600 furnace, Ivoclar Vivadent; sintering program P7 with Software V4.0) and glazed according to the manufacturer’s recommendation.

In the Ti-4Y/5Y group, a titanium abutment (esthetic abutment CC RP) was screwed to the implant. The manufacturing process of the 4Y/5Y-PSZ crowns (TT-GT) was similar to that of the 3Y-TZP crowns, and the sizes of the crowns were consistent.

In the Zir-3Y group, a Ti base (universal base RP 1.5 mm, Nobel Biocare) was screwed onto the implant. The body was connected to the implant, a digital scanner was used to scan the model, and the digital data were transferred to the CAD/CAM system (Exocad Rijeka 3.1, Exocad GmbH, Darmstadt, Germany). A zirconia abutment was designed on the Ti base and milled (K5, vhf camfacture, Ammerbuch, Germany) from a presintered zirconia block (Zenostar T, 3Y-TZP) and sintered in accordance with the manufacturer’s directives. Then, the zirconia abutment was cemented onto the Ti base using a self-curing resin luting agent according to the manufacturer’s instructions. 3Y-TZP crowns were made as described for the Ti-3Y group.

In the Zir-4Y/5Y group, a Ti-base-zirconia abutment was manufactured and screwed to the implant as described for the Zir-3Y group. Eight 4Y/5Y-PSZ crowns (TT-GT) were manufactured. The manufacturing process was similar to that in the Ti-4Y/5Y group.

For crown design and production, a uniform size was specified for all crowns. The margin width was specified to be 1 mm. For the buccal and lingual sides, the thickness was 1 mm for the cervical section, 1.5 mm for the middle section, and 2 mm for the incisal section. The thicknesses of the crowns were confirmed using a digital calliper (500–784, Mitutoyo, Kawasaki, Japan).

Prior to cementation, a piece of polytetrafluoroethylene (PTFE, Teflon) tape was used to cover the screw access of the abutment. The crowns were luted onto the abutments using resin-modified glass ionomer (RMGI) luting cement (RelyX™ Luting 2, 3 M, Minnesota, USA). The cemented crowns were kept in a 100% humidifying chamber for 24 h before the crown removal treatment. A total of 8 crowns were cemented on the abutment–implant fixture specimens for each group.

A K-type thermocouple thermometer (TA612-C, TASI, Suzhu, China) with three channels for temperature measurement was used in the temperature test. Small access holes were drilled in the maxillary resin model. Thermal probes were inserted through the holes and placed in direct contact with the implant at three locations: the abutment region, the middle segment, and the apical region. Flowable resin was then injected into the access holes and light-cured to securely fix the probes in place without loosening or displacement. The temperature changes detected in the three channels were monitored and recorded on a computer.

Laser debonding and temperature measurement

An Er: YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) with a sapphire tip 1.3 mm in diameter and 6.5 mm in length was used for laser irradiation. The laser parameters were set at 600 mJ and 10 Hz, an energy density of 45.23 J/cm2, QSP mode, an air spray at 6/8, and a water spray at 0/8 [25, 28].

The labial surface was scanned from cervical to incisal for 30 s with the laser beam vertical to the surface at a focal distance of 3 mm and then cooled with water vapour for 30 s. Then, the same laser irradiation was applied to the lingual surface for 30 s, after which the samples were cooled for 30 s. No irradiation was performed on the proximal surface. This operation was repeated on the labial and lingual sides until the restoration showed signs of carbonization and darkening of colour, indicating disintegration of the cement by the laser energy. At this point, crown dislodgement was assessed using a crown remover to shake and remove the ceramic crown. If the crown could not be dislodged, another round of laser debonding operations was performed as described previously until the oscillator could remove the ceramic crown. The time and temperature were continuously recorded throughout the entire crown removal process. The mean temperature increase and the maximum temperature increase at the three points were calculated, and the removal time was recorded.

SEM

After Er: YAG laser laser debonding operation, one crown from each group was mounted on a metallic stub, coated with gold, and observed by SEM (CS3400, CamScan, Cambridge, UK) at a magnification of 1000×.

Statistical analysis

Sample size calculation was performed using G*Power version 3.1.9.72 [21, 23, 29], and the appropriate number of specimens was detected as 8 per group (effect size = 0.65; actual power = 83.2%; power = 80.0%; α = 0.05). The effect size was based on the results of previous studies [21, 23]. The normality of data was assessed with the Shapiro–Wilk test. Since the mean temperature increase, maximum temperature increase and removal time were normally distributed, one-way analysis of variance (ANOVA) was used for analysis, and post hoc comparisons were made with the Bonferroni correction (p = 0.05).

Results

All 32 zirconia crowns that were cemented on the abutments were successfully debonded with an Er: YAG laser and removed in one piece with no signs of fracture on direct visual or SEM observation. The luting cement appeared carbonized and deteriorated and was easily scratched off from the abutment surface and from the inside of the zirconia crown with a scaler.

The typical curves of the temperature variations during Er: YAG laser removal treatment are shown in Fig. 1. The starting temperature was room temperature. The results show that the temperature of the abutment region (blue curve) rapidly increased with the laser debonding operation but then rapidly decreased with the water cooling. Owing to heat conduction, the amplitude of the temperature change in the middle region of the implant (red curve) was relatively small and lagged behind that in the abutment region. The apical region of the implant (green curve) experienced the least thermal effect and was even more affected by the cooling procedure in the later stage.

Fig. 1.

Fig. 1

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Typical curves of the temperature variations at three points (the abutment region, middle of the implant, and apical region of the implant) during Er: YAG laser removal treatment

Table 2 shows the average and maximum temperature increases in the four groups at the three sites: the abutment region (∆T1, ∆T1 MAX), the middle region (∆T2, ∆T2 MAX), and the apical region of the implant (∆T3, ∆T3 MAX). In addition, the crown retrieval time and statistical analysis results are shown.

Table 2.

The average and maximum temperature increases (mean ± SD) in the four groups at the three sites: the abutment region (∆T1, ∆T1 MAX), the middle region (∆T2, ∆T2 MAX), and the apical region of the implant (∆T3, ∆T3 MAX), and the crown removal times (mean ± SD)

group average temperature rise (°C) maximum temperature rise (°C) removal times (s)
∆ T1 ∆T2 ∆T3 ∆T1 MAX ∆T2 MAX ∆T3 MAX
Ti-3Y 3.21 ± 0.72 Aa 1.64 ± 0.75 Aa -0.01 ± 0.37 Aa 8.75 ± 0.90 Aa 3.26 ± 1.13 Aa 0.64 ± 0.51 Aa 394.13 ± 54.38 Aa
Ti-4Y/5Y 3.19 ± 0.48 Ab 1.37 ± 0.66 Ab -0.40 ± 1.03 Ab 9.36 ± 0.39 Ab 2.93 ± 1.63 Ab 0.66 ± 0.60 Ab 341.88 ± 40.44 Bb
Zir-3Y 2.99 ± 0.64 Ba 1.12 ± 0.91 Ba -0.94 ± 1.47 Ba 8.86 ± 0.76 Ba 3.23 ± 1.00 Ba 1.29 ± 1.01 Ba 461.13 ± 115.43 Ca
Zir-4Y/5Y 2.70 ± 0.46 Bb 1.23 ± 0.74 Bb -0.59 ± 0.63 Bb 9.59 ± 0.45 Cb 3.49 ± 0.68 Bb 0.83 ± 0.76 Bb 359.25 ± 27.03 Db
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The same upper-case letters in the same column indicate when the kind of abutment is the same, there is no significant difference between different crown groups (p>0.05)

The same lower-case letters in the same column indicate when the kind of crown material is the same, there is no significant difference between different abutment groups (p>0.05)

With respect to the average increase in implant temperature, ∆T1, ∆T2, and ∆T3 did not significantly differ among the different abutment and crown groups, indicating that the different types of abutment and zirconia materials had no obvious effects on the average increase in temperature during Er: YAG laser debonding.

Regarding the maximum temperature increase, when the abutment was kept the same, the ∆T1 MAX in the Ti-3Y group was lower than that in the Ti-4Y/5Y group, but the difference was not significant (p > 0.05). However, the ∆T1 MAX in the Zir-3Y group was significantly lower than that in the Zir-4Y/5Y group (p < 0.05). No significant differences in the ∆T2 MAX or ∆T3 MAX were detected between the different groups (Fig. 2).

Fig. 2.

Fig. 2

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The ∆T1 MAX and removal times (mean ± SD) in the four groups. The horizontal lines represent no significant differences between groups (p > 0.05). The asterisk (*) above the horizontal line indicates a significant difference between groups (p < 0.05)

When the same zirconia crown materials were used, the ∆T1 MAX in the Ti groups was lower than that in the Zir groups, but the differences were not significant (p > 0.05) (Fig. 2). Notably, the maximum temperature increase in the abutment region was close to 10 °C. Only one time did the temperature rise exceeded 10 °C (the sixth sample in the Zir-4Y/5Y group); and the temperature exceeded 10 °C for 2 s and reached a maximum of 10.4 °C (Fig. 3).

Fig. 3.

Fig. 3

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Every whisker plot shows ∆T1 MAX for 8 zirconia crowns of each group during zirconia crown removal treatment

The mean removal times were 394.13 (± 54.38), 341.88 (± 40.44), 461.13 (± 115.43) and 359.25 (± 27.03) seconds in the Ti-3Y, Ti-4Y/5Y, Zir-3Y, and Zir-4Y/5Y groups, respectively. Among them, the longest time for the crown removal procedure was needed in the Zir-3Y group, and the shortest time for the crown removal procedure was needed in the Ti-4Y/5Y group. When the same abutment was used, compared with the 4Y/5Y groups, the 3Y groups required significantly longer removal times (p < 0.05). When the same zirconia crown material was used, the removal time in the Ti groups was shorter than that in the Zir groups, but the differences were not significant (p > 0.05) (Fig. 2).

SEM examinations did not reveal any signs of microcracks in the tested zirconia crown surfaces after laser debonding treatment (Fig. 4).

Fig. 4.

Fig. 4

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Images of the surface morphology of zirconia crowns of the four groups under SEM (1000× magnification). a: Ti-3Y group, b: Ti-4Y/5Y group, c: Zir-3Y group, d: Zir-4Y/5Y group

Discussion

In the last twenty years, the erbium laser debonding method has been increasingly applied to the removal of natural tooth restorations [28, 30, 31]. This method is also highly important for the repair or maintenance of cement-retained implant restorations [20, 32]. However, the debonding process is challenging and may cause heat transfer to the implant–bone interface, leading to a potential risk of irreversible tissue damage, but relevant research is limited [16, 33]. Studies on the erbium laser debonding performance for new-generation zirconia materials are limited. Therefore, this study investigated the Er: YAG laser debonding performance for monolithic translucent multilayer zirconia implant crowns, including comparisons of debonding efficiency and thermal safety.

The first null hypothesis that the type of zirconia crown would not affect the temperature increase and the debonding time was partly rejected. The ∆T1 MAX in the Zir-3Y group was significantly lower than that in the Zir-4Y/5Y group, and compared with the 4Y/5Y groups, the 3Y groups had significantly longer removal times. The second null hypothesis that the type of abutment would not affect the temperature increase or the debonding time was accepted.

The findings of this in vitro investigation confirmed that all zirconia crowns could be efficiently and intactly removed by the Er: YAG laser debonding method. No damage to any abutment or crown was visually detected. The SEM results also suggested the absence of microcracks in the zirconia crowns, indicating the potential for reuse of the implant restorations. This is consistent with previous research findings. In Deeb JG and Elkharashi A’s studies, SEM and energy-dispersive X-ray spectroscopy (EDS) revealed no structural changes or damage to either abutments or restorations after removal procedures performed using an Er: YAG laser. The cement appeared to stay mostly in the crown. Additionally, no carbonization of the zirconia implant abutment or zirconia crown was observed [16, 27]. Previous studies have reported that cement appeared deteriorated mainly at the crown–cement interface and that within the cement itself, carbonized cement on the abutment or on the intaglio surface of the crown was easily scratched off with a dull instrument [18, 30, 34]. These results are determined by the mechanism of laser debonding. Since zirconia does not have a strong absorption on FTIR spectra at the Er: YAG laser wavelength, it is supposed that adequate laser energy may be transmitted through it and specifically absorbed by the luting cement containing water molecules and residual monomers, causing degradation of cement by thermal ablation and photoablation. The efficiency of laser debonding is positively correlated with the amount of transmitted laser energy, which is affected by the composition, thickness and shade of ceramic restorations [21, 35–38].

When a rotary cutting instrument or laser debonding method is used to remove restorations from an implant abutment, the generated heat may be transferred to the implant–bone interface, and the effect of overheating the implant–bone interface may result in bone necrosis and soft tissue encapsulation, leading to implant failure [16, 33, 34]. Eriksson and Albrektsson reported that transitory hyperaemia occurred at bone temperatures between 40 °C and 41 °C. When the osseous temperature was increased to 47 °C (10 °C temperature increase) for 1 min, integration was significantly reduced, leading to irreversible damage [39, 40]. In our research, the maximum temperature increase in the abutment region was close to 10 °C. Only once did the temperature increase to 10.4 °C, which lasted for only 2 s. Our experimental design involved a single 30-second laser operation, followed by 30 s of water vapour cooling. The experimental results revealed no constant heat increase or heat accumulation after laser irradiation. After the temperature peaks occurred, the temperature immediately decreased. This laser operation design can ensure thermal safety and has important reference significance for clinical debonding operations.

In this study, the maximum temperature increase at the abutment and implant was recorded throughout the entire debonding procedure. According to the results, the obvious temperature increase caused by laser energy occurred mainly at the abutment. Compared with the 3Y groups, the 4Y/5Y groups always exhibited greater maximum temperature increases. There were significant differences between the Zir-3Y and Zir-4Y/5Y groups. This may be because, compared with 3Y-TZP, 4Y/5Y-PSZ have a higher yttria content, from 3 mol% to 4 mol% or 5 mol%, to increase the amount of the cubic phase, which can reduce light scattering and birefringence, thus improving the transmittance of the zirconia. Consequently, more laser energy may be transmitted through the restoration and react with the cement, leading to a greater thermal effect and a shorter duration needed for removal [41, 42]. As the results showed, when the abutment was of the same kind, the 4Y/5Y groups always exhibited shorter duration times than the 3Y groups did, which is consistent with the findings of previous studies. Suliman S [43] compared the time required for an Er: YAG laser (335 mJ; 15 Hz; 5 W) to remove different types of zirconia and lithium disilicate crowns from teeth and founded that the retrieval time was influenced by the yttria content of the zirconia; the times needed for crown debonding were 12.46 ± 4.17 min in the 3Y-TZP group, 10.30 ± 3.33 min in the 4Y-TZP group, 4.03 ± 1.62 min in the 5Y-TZP group, and 2.08 ± 0.92 min in the lithium disilicate group. Kurtulmus-Yilmaz S [29] reported that compared with 4Y-TZP crowns, 5Y-TZP crowns were debonded from Ti bases significantly faster. The zirconia crown retrieval time with the erbium laser was influenced by the yttria content of the zirconia, with the retrieval time decreasing with increasing yttria content. This finding suggests that if the restorations are composed of novel, higher yttria-containing zirconia materials, more laser energy might be transmitted to the cement layer and shorter operating times may be needed to remove the restorations.

Zirconia materials, including 3Y-TZP and 4Y/5Y-PSZ, possess extremely low thermal conductivity and excellent thermal shock resistance [44, 45]. The results of this experiment showed that when the zirconia crown was of the same kind, the Zir abutment groups presented greater temperature increases (∆T1 MAX) and longer duration times than the Ti abutment groups did, but no significant differences were detected. A plausible explanation is that laser irradiation induces temperature elevation in the abutment. Owing to the low thermal conductivity of zirconia, heat dissipation is restricted, thereby leading to heat accumulation. In comparison, titanium features higher thermal conductivity and enables relatively efficient heat diffusion [44–46]. In Mason AG’s research [34], they also studied the differences in temperature increases between titanium abutments and zirconia abutments when a zirconia crown was removed by drilling to access the screw channel or sectioning a crown with a high-speed dental handpiece. The results showed that the heat transferred to the implant–bone interface was significantly greater for the titanium abutment than for the zirconia abutment. The inconsistency between these results and our findings may be due to the use of different experimental designs and debonding methods.

As shown by the typical curve graph of the temperature variations, the temperature in the abutment region rapidly increased with laser irradiation but then rapidly decreased with cooling by water vapour. The temperature fluctuation amplitude was the greatest at this point. No constant heat increase or heat accumulation was observed at either the abutment or the implant. Owing to heat conduction, the amplitude of the temperature change in the middle region of the implant was relatively small and lagged behind that in the abutment region. Notably, the temperature in the apical region of the implant did not increase; in contrast, the apical region was more affected by the cooling effect, and the temperature decreased in the later stage. Previous studies have focused mainly on the temperature increase at the coronal aspect of the abutment/implant; thus, this study contributes to the literature [16, 27].

The Er: YAG laser parameters used in this study were based on our previous series studies and other similar studies [25, 30, 33, 42]. The Er: YAG laser energy transmitted through zirconia ceramics depends on the ceramic type, shade and thickness, influencing the debonding duration and heat generation [21, 29, 42]. In this study, Er: YAG laser irradiation and water vapour cooling procedures were designed separately. This occurred because when the laser was irradiated with water irrigation, most of the laser energy was absorbed by the water on the surface of the restorations, causing explosions and significantly reducing the effective laser energy transmitted through the ceramic, leading to decreased laser debonding efficiency. Moreover, the microexplosion of water molecules may cause microcracks in the surface of the restorations, which is not conducive to the reuse of restorations. The separate application of laser irradiation and water vapour cooling was inconsistent with that in some previous studies, but some studies have highlighted that intermittent irradiation and cooling can be considered in future studies to find more clinically viable settings [19]. This study documented the efficiency and safety of specific Er: YAG laser debonding settings for the retrieval of zirconia implant-supported crowns, and the results support the convenient clinical application of this methodology.

This in vitro study investigated the effectiveness and safety of debonding cement-retained implant restorations with an Er: YAG laser. One limitation of the study is that intraoral debonding operations are not as convenient as in vitro models are, as they are affected by factors such as tooth position and mucous membranes, which can influence the debonding time and efficacy. Another limitation is that the temperature increase in the alveolar bone and the long-term impact on implant restorations need to be verified by further clinical studies. In addition, the temperature rise of the abutment and implant, as well as the debonding duration, are closely associated with the Er: YAG laser debonding protocol adopted. Accordingly, the findings of this study are only applicable to the debonding procedure described herein.

Conclusions

Within the limitations of this study, the following conclusions can be drawn: the Er: YAG laser can be used to safely and effectively remove cement-retained implant zirconia restorations. The debonding time and temperature increase were affected by the type of zirconia crown and were not affected by the type of abutment. Monolithic translucent multilayer zirconia crowns needed less debonding time and exhibited greater temperature increases in the implant. This study provides a safe and effective Er: YAG laser debonding operation protocol, which has important implications for clinical applications.

Acknowledgements

Not applicable.

Author contributions

XYZ, ZYY, CLG: Conception, Formal analysis, Investigation, Statistical analysis, Writing- Original Draft; XMW, QL, CLG, HTD: Conceptualization, Methodology, Resources, Data acquisition and interpretation, Writing-Review &amp; Editing, Supervision. The authors read and approved the final manuscript.

Funding

This research was funded by the National High-Level Hospital Clinical Research Funding (2025-PUMCH-A-094).

Data availability

The complete data and materials described in the research article are freely available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Chunlan Guo, Email: guochunlan@pumch.cn.

Haitao Dong, Email: donghaitao@pumch.cn.

References

  • 1.Kraus RD, Espuelas C, Hämmerle CHF, Jung RE, Sailer I, Thoma DS. Five-year randomized controlled clinical study comparing cemented and screw-retained zirconia-based implant-supported single crowns. Clin Oral Implants Res. 2022;33(5):537–47. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Ramamoorthi M, Narvekar A, Esfandiari S. A meta-analysis of retention systems for implant-supported prostheses in partially edentulous jaws. J Prosthet Dent. 2017;118(5):587–95. [DOI] [PubMed] [Google Scholar]
  • 3.Ibrahim EA, Khamis MM, Ezzelarab S, Abdelhamid AM. Retention of zirconia crowns to titanium bases with straight versus angled screw access channels: an invitro study. BMC Oral Health. 2023;23(1):458. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Dini C, Borges GA, Costa RC, Magno MB, Maia LC, Barão VAR. Peri-implant and esthetic outcomes of cemented and screw-retained crowns using zirconia abutments in single implant-supported restorations-A systematic review and meta-analysis. Clin Oral Implants Res. 2021;32(10):1143–58. [DOI] [PubMed] [Google Scholar]
  • 5.Kraus RD, Hjerppe J, Naenni N, Balmer M, Jung RE, Thoma DS. A 7.5-year randomized controlled clinical study comparing cemented and screw-retained one-piece zirconia-based implant-supported single crowns. Clin Oral Implants Res. 2024;35(12):1669–75. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Sailer I, Mühlemann S, Zwahlen M, Hämmerle CH, Schneider D. Cemented and screw-retained implant reconstructions: a systematic review of the survival and complication rates. Clin Oral Implants Res. 2012;23(Suppl 6):163–201. [DOI] [PubMed] [Google Scholar]
  • 7.de Pereira HC, de Oliveira Limirio AK, Cavalcanti do Egito Vasconcelos JPJ, Pellizzer B, Dantas de Moraes EP. Mechanical behavior of titanium and zirconia abutments at the implant-abutment interface: A systematic review. J Prosthet Dent. 2024;131(3):420–6. [DOI] [PubMed] [Google Scholar]
  • 8.Vazouras K, Gholami H, Margvelashvili-Malament M, Kim YJ, Finkelman M, Weber HP. An Esthetic Evaluation of Different Abutment Materials in the Anterior Maxilla: A Randomized Controlled Clinical Trial Using a Crossover Design. J Prosthodont. 2022;31(8):673–80. [DOI] [PubMed] [Google Scholar]
  • 9.van Erp AL, van der Winden E, Molenaar MC, Royakkers EJ, van Daelen ACL, de Kok P, Gresnigt MMM. Bilayered ceramic anterior restorations with reinforcement of the incisal edge by using lithium disilicate: A multicenter retrospective survival analysis with a maximum of 6-year follow-up. J Prosthet Dent. 2023;129(5):718–24. [DOI] [PubMed] [Google Scholar]
  • 10.Pjetursson BE, Sailer I, Latyshev A, Rabel K, Kohal RJ, Karasan D. A systematic review and meta-analysis evaluating the survival, the failure, and the complication rates of veneered and monolithic all-ceramic implant-supported single crowns. Clin Oral Implants Res. 2021;32(Suppl 21):254–88. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Vardhaman S, Borba M, Kaizer MR, Kim D, Zhang Y. Wear behavior and microstructural characterization of translucent multilayer zirconia. Dent Mater. 2020;36(11):1407–17. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Kang CM, Peng TY, Shimoe S. Color accuracy of different types of monolithic multilayer precolored zirconia ceramics. J Prosthet Dent. 2020;124(6):789.e1-789.e7. [DOI] [PubMed] [Google Scholar]
  • 13.Walczak K, Meißner H, Range U, Sakkas A, Boening K, Wieckiewicz M, Konstantinidis I. Translucency of Zirconia Ceramics before and after Artificial Aging. J Prosthodont. 2019;28(1):e319–24. [DOI] [PubMed] [Google Scholar]
  • 14.Possebon APDR, Schuster AJ, Chagas-Júnior OL, Pinto LR, Faot F. Prosthetic aftercare, mastication, and quality of life in mandibular overdenture wearers with narrow implants: A 3-year cohort study. J Dent. 2021;115:103880. [DOI] [PubMed] [Google Scholar]
  • 15.Malpartida-Carrillo V, Tinedo-Lopez PL, Ortiz-Culca F, Guerrero ME, Amaya-Pajares SP. Techniques for retrievability and for registering screw access holes in cement-retained implant-supported prostheses: A scoping review of the literature. J Prosthet Dent. 2020;123(3):427–33. [DOI] [PubMed] [Google Scholar]
  • 16.Deeb JG, Bencharit S, Dalal N, Abdulmajeed A, Grzech-Leśniak K. Using Er:YAG laser to remove lithium disilicate crowns from zirconia implant abutments: An in vitro study. PLoS One. 2019;14(11):e0223924. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Deeb JG, Crowell A, Richey KH, Bencharit S, Carrico CK, Williams TL, Grzech-Leśniak K. Vitro Study of Laser-Assisted Prefabricated Ceramic Crown Debonding as Compared to Traditional Rotary Instrument Removal. Mater (Basel). 2022;15(10):3617. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 18.Deeb JG, McCall C, Carrico CK, Dahlke WO, Grzech-Leśniak K. Retrieval of Prefabricated Zirconia Crowns with Er,Cr:YSGG Laser from Primary and Permanent Molars. Mater (Basel). 2020;13(23):5569. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Viski IS, Lee JD, Scialabba R, Lee SJ. Retrieval of cement-retained zirconia implant-supported crowns with an Er,Cr:YSGG laser. J Prosthet Dent. 2025;134(2):444–9. [DOI] [PubMed] [Google Scholar]
  • 20.Limpuangthip N, Hlaing NHMM, Lee JH, Lee JD, Lee SJ. Laser-assisted retrieval of cement-retained implant-supported restorations from implant abutments: A systematic review of related factors. J Dent. 2025;162:106076. [DOI] [PubMed] [Google Scholar]
  • 21.Morford CK, Buu NC, Rechmann BM, Finzen FC, Sharma AB, Rechmann P. Er:YAG laser debonding of porcelain veneers. Lasers Surg Med. 2011;43(10):965–74. [DOI] [PubMed] [Google Scholar]
  • 22.Cai P, Zhuo Y, Lin J, Zheng Z. Er:YAG laser removal of zirconia crowns on titanium abutment of dental implants: an in vitro study. BMC Oral Health. 2022;22(1):396. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.El-Sheikh NA, Wahsh MM, Hussein GA. Laser debonding of ultrathin occlusal veneers fabricated from different CAD/CAM ceramic materials. BMC Oral Health. 2024;24(1):570. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Karagoz-Yildirak M, Gozneli R. Evaluation of rebonding strengths of leucite and lithium disilicate veneers debonded with an Er:YAG laser. Lasers Med Sci. 2020;35(4):853–60. [DOI] [PubMed] [Google Scholar]
  • 25.Zhang X, Dong H, Guo C, Zhang X, Zhang D, Wu X, Zhao J. Effects of laser debonding treatment on the optical and mechanical properties of all-ceramic restorations. Lasers Med Sci. 2021;36(7):1497–504. [DOI] [PubMed] [Google Scholar]
  • 26.Grzech-Leśniak K, Bencharit S, Dalal N, Mroczka K, Deeb JG. In Vitro Examination of the Use of Er:YAG Laser to Retrieve Lithium Disilicate Crowns from Titanium Implant Abutments. J Prosthodont. 2019;28(6):672–6. [DOI] [PubMed] [Google Scholar]
  • 27.Elkharashi A, Grzech-Leśniak K, Deeb JG, Abdulmajeed AA, Bencharit S. Exploring the use of pulsed erbium lasers to retrieve a zirconia crown from a zirconia implant abutment. PLoS ONE. 2020;15(6):e0233536. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Alikhasi M, Monzavi A, Ebrahimi H, Pirmoradian M, Shamshiri A, Ghazanfari R. Debonding Time and Dental Pulp Temperature With the Er, Cr: YSGG Laser for Debonding Feldespathic and Lithium Disilicate Veneers. J Lasers Med Sci. 2019;10(3):211–4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Birand C, Kurtulmus-Yilmaz S. Evaluation of Er,Cr:YSGG laser irradiation for debonding of zirconia hybrid abutment crowns from titanium bases. Lasers Med Sci. 2022;37(6):2675–85. [DOI] [PubMed] [Google Scholar]
  • 30.Rechmann P, Buu NC, Rechmann BM, Finzen FC. Laser all-ceramic crown removal and pulpal temperature–a laboratory proof-of-principle study. Lasers Med Sci. 2015;30(8):2087–93. [DOI] [PubMed] [Google Scholar]
  • 31.Giraldo Cifuentes H, Gómez JC, Guerrero ANL, Muñoz J. Effect of an Er,Cr:YSGG Laser on the Debonding of Lithium Disilicate Veneers With Four Different Thicknesses. J Lasers Med Sci. 2020;11(4):464–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Matys J, Romeo U, Mroczka K, Grzech-Leśniak K, Dominiak M. Temperature Changes and SEM Effects of Three Different Implants-Abutment Connection during Debridement with Er:YAG Laser: An Ex Vivo Study. Mater (Basel). 2019;12(22):3748. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.Deeb JG, Grzech-Leśniak K, Brody ER, Matys J, Bencharit S. Erbium laser-assisted ceramic debonding: a scoping review. J Prosthodont. 2022;31(9):e100–24. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Mason AG, Sutton A, Turkyilmaz I. An investigation of heat transfer to the implant-bone interface when drilling through a zirconia crown attached to a titanium or zirconia abutment. J Prosthet Dent. 2014;112(5):1119–25. [DOI] [PubMed] [Google Scholar]
  • 35.Ghazanfari R, Azimi N, Nokhbatolfoghahaei H, Alikhasi M. Laser Aided Ceramic Restoration Removal: A Comprehensive Review. J Lasers Med Sci. 2019;10(2):86–91. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Rechmann P, Buu NC, Rechmann BM, Le CQ, Finzen FC, Featherstone JD. Laser all-ceramic crown removal-a laboratory proof-of-principle study-phase 1 material characteristics. Lasers Surg Med. 2014;46(8):628–35. [DOI] [PubMed] [Google Scholar]
  • 37.Kellesarian SV, Ros Malignaggi V, Aldosary KM, Javed F. Laser-assisted removal of all ceramic fixed dental prostheses: A comprehensive review. J Esthet Restor Dent. 2018;30(3):216–22. [DOI] [PubMed] [Google Scholar]
  • 38.Tak O, Sari T, Arslan Malkoç M, Altintas S, Usumez A, Gutknecht N. The effect of transmitted Er:YAG laser energy through a dental ceramic on different types of resin cements. Lasers Surg Med. 2015;47(7):602–7. [DOI] [PubMed] [Google Scholar]
  • 39.Gungormus M, Erbasar GNH. Transient Heat Transfer in Dental Implants for Thermal Necrosis-Aided Implant Removal: A 3D Finite Element Analysis. J Oral Implantol. 2019;45(3):196–201. [DOI] [PubMed] [Google Scholar]
  • 40.Cakan U, Cakan M, Delilbasi C. Evaluation of Heat Transfer to the Implant-Bone Interface During Removal of Metal Copings Cemented onto Titanium Abutments. Int J Prosthodont. 2016;29(3):290–2. [DOI] [PubMed] [Google Scholar]
  • 41.Zhang Y, Lawn BR. Novel Zirconia Materials in Dentistry. J Dent Res. 2018;97(2):140–7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 42.Zhang X, Dong H, Wu X, Zhao J, Jiang Q. Evaluation of Er:YAG laser energy transmitted through novel dental zirconia ceramics. Dent Mater J. 2023;42(5):669–75. [DOI] [PubMed] [Google Scholar]
  • 43.Suliman S, Sulaiman TA, Deeb JG, Abdulmajeed A, Abdulmajeed A, Närhi T. Er:YAG laser debonding of zirconia and lithium disilicate restorations. J Prosthet Dent. 2024;131(2):253.e1-253.e6. [DOI] [PubMed] [Google Scholar]
  • 44.Tzanakakis E, Tzoutzas I, Kontonasaki E. Zirconia: Contemporary views of a much talked material: Structure, applications and clinical considerations. Hellenic Stomatolog. 2013;57:101–37. [Google Scholar]
  • 45.Koutayas SO, Vagkopoulou T, Pelekanos S, Koidis P, Strub JR. Zirconia in dentistry: part 2. Evidence-based clinical breakthrough. Eur J Esthet Dent. 2009;4(4):348–80. [PubMed] [Google Scholar]
  • 46.Tharp M, Jauregui-Ulloa J, De Souza GM, Salazar Marocho S. Thermal Dynamics of Laser-Irradiated Trilayer Bonded-Zirconia Structures. J Funct Biomater. 2025;16(4):137. [DOI] [PMC free article] [PubMed] [Google Scholar]

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