UNIVERSIDADE ESTADUAL PAULISTA
“JÚLIO DE MESQUITA FILHO”
Instituto de Ciência e Tecnologia
Campus de São José dos Campos
ORIGINAL ARTICLE DOI: https://doi.org/10.4322/bds.2025.e4581
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Braz Dent Sci 2025 Jan/Mar;28 (1): e4581
This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
Effect of angulation of 3D printed resin provisional bridges:
an
in vitro
study on hardness and fracture loading
Efeito da angulação de pontes provisórias de resina impressa em 3D: um estudo
in vitro
sobre a dureza e carregamento à fratura
Laís Maria de Barros BATISTA1 , Yan Victor Silva de SANTANA2 , Maria Terêza Lopes de Moura BORBA1 ,
Tayná Karla Arruda e SILVA1 , Clarisse Maria Luiz SILVA2 , Antonio José TÔRRES NETO2 , Larissa Araújo Lopes BARRETO2 ,
Viviane Maria Gonçalves de FIGUEIREDO3
1 - Universidade Federal de Pernambuco, Recife, PE, Brazil.
2 - Universidade do Estado de São Paulo, Instituto de Ciência e Tecnologia, Departamento de Materiais Odontológicos e Prótese, São José
dos Campos, SP, Brazil.
3 - Universidade Federal de Pernambuco, Departamento de Prótese e Cirurgia Oral e Facial, Recife, PE, Brazil.
How to cite: Batista LMB, Santana YVS, Borba MTLM, Silva TKA, Silva CML, Torres Neto AJ, Barreto LAL, Figueiredo VMG. Effect of
angulation of 3D printed resin provisional bridges: an
in vitro
study on hardness and fracture loading. Braz Dent Sci. 2025;28(1):e4581.
https://doi.org/10.4322/bds.2025.e4581
ABSTRACT
Objective: to evaluate the effect of printing angle of three-dimensional (3D) printed resin temporary bridges,
through an in vitro study on hardness and fracture loading. Material and Methods: Specimens xed bridges
with three elements (N=5) and block specimens (N=1), were distributed among the experimental groups based
on different printing angles: 0°, 45°, and 90°. Surface analysis using a scanning electron microscope (SEM)
was conducted on one specimen from each experimental group. Hardness testing was then performed, with
the specimens receiving ve measurements on a Vickers microhardness tester and for fracture loading testing,
force was applied using a piston attached to a testing machine. Finally, the bridge specimens were evaluated
for fracture. Fracture loading and hardness data were subjected to a Anova 1 Factor statistical test (p<0.05),
while the ndings from surface analysis and fractures were analyzed qualitatively. Results: On the surfaces of
the specimens, printing layers were mainly observed in the 90° group for block-type specimens. For hardness
analysis, the 3D printing angle showed statistical signicance between groups (P=0.000), while no signicant
difference was found for fracture loading (P=0.177). Finally, there was a prevalence of all failures for the 0°
and 90° groups and retainer fracture for the 45° group. Conclusion: Different angles of provisional bridges
manufactured by 3D printed resin affect hardness, but do not interfere with fracture loading.
KEYWORDS
Angulation; Dental prosthesis; Digital technology; Provisional bridges; Three-dimensional printing.
RESUMO
Objetivo: avaliar o efeito da angulação de impressão das pontes provisórias de resina impressa tridimensional
(3D), através de um estudo
in vitro
sobre dureza e resistência à fratura. Material e Métodos: Espécimes pontes
xas de 03 elementos (N=5) e espécimes em bloco (N=1) foram distribuídos entre os grupos experimentais
quanto às diferentes angulações de impressão, 0°, 45°, 90°. Análise supercial em microscópio eletrônico de
varredura (MEV) foi realizada em ambos tipos de espécimes (N=1). No teste de dureza, os espécimes receberam
05 medições em microdurômetro Vickers e no teste de carregamento à fratura, a força foi aplicada através de
um pistão xado a uma máquina de ensaio. Por m, os espécimes em forma de ponte foram avaliados quanto
à fratura. Os dados de carregamento à fratura e dureza foram submetidos ao teste estatístico Anova 1 Fator
(p< 0.05), os achados da análise supercial e fratura foram analisados qualitativamente. Resultados: Nas
superfícies dos espécimes, as camadas de impressão são observadas principalmente no grupo 90° em espécime
tipo bloco. Para a análise de dureza, a angulação da impressão 3D foi estatisticamente signicativa entre grupos
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Braz Dent Sci 2025 Jan/Mar;28 (1): e4581
Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
INTRODUCTION
Provisional prostheses must be made from
materials capable of withstanding the changes
in the oral environment and occlusal forces
for a certain period, especially in cases of
oral rehabilitation lasting months or implant-
supported prostheses [1,2]. In the search
for long-lasting provisional alternatives, the
fabrication of such prostheses using Computer-
Aided Design – Computer-Aided Manufacturing
(CAD/CAM) technology has become more
popular, straightforward, and accessible in
dental practice [1,3,4]. Studies such as those by
Myagmar et al. [5] and Al-Qahtani et al. [6] indicate
that three-dimensional (3D) printed provisional
resins are suitable as temporary restorative
materials for extended clinical use. Additionally,
research by Pereira et al. [7] highlights the
dimensional accuracy achievable with 3D-printed
provisional crowns, which is crucial for ensuring
stability and fit in long-term temporary
restorations.
Polymer-based materials are widely used to
produce dental crowns using additive technology.
However, studies evaluating the use of 3D
printed materials in Dentistry in terms of their
surface and mechanical properties, including
exural strength, surface roughness, hardness,
and aesthetics, remain limited [7,8]. Several
factors are still not established for 3D printed
provisional resins, such as the type of printer,
printing parameters, layer thickness, and post-
processing, which are crucial for understanding
their impact on mechanical properties and the
failure of printed restorations [9,10].
Studies have shown that print orientation is
a factor that seems to inuence the mechanical
properties of 3D printed resins due to the
distinct polymerization of layers during the
printing process [9,11,12,13]. Thus, this printing
parameter presents a gap in the literature, and
building scientic evidence will help improve
the quality of dental restorations and their
performance in daily practice [7,9,11].
Based on the above, the objective was to
evaluate the effect of the orientation of 3D printed
resin provisional bridges through an in vitro study
on hardness and fracture loading. The hypothesis
tested was: Null Hypothesis - There will be no
statistically signicant difference regarding the
orientation of 3D printed resin provisional bridges
in relation to hardness and fracture loading.
MATERIAL AND METHODS
Specimen fabrication
In this study, two types of specimens
were produced: xed bridges with 3 units for
mechanical fracture testing and blocks for
hardness testing. Both specimens were also used
for surface analysis.
For the xed bridge with 3 units, a model
with metal cylindrical abutments simulating a
pontic for element 25 and abutments for elements
24 and 26 was created with the following
parameters: the conical cylindrical abutments
with a 6° taper had a height of 5.4 mm, with
widths of 6.0 mm (premolar) and 7.4 mm
(molar), and a cervical nish with a chamfer of
0.8 mm thickness [10]. The occlusal thickness of
the bridge was 1.5 mm, the circular connector
had a dimension of 16.0 mm2, and the distance
from the base of the connector to the model was
7 mm [11].
The metal preparations were scanned with
a bench scanner to reproduce the design in CAD.
This generated a Standard Tessellation Language
(STL) file, which was transferred to a dental
design software (exocad DentalCAD 2.2 Valetta;
exocad GmbH) to design the fixed bridge,
which had a cement space of 0.08 mm [1,10].
Meanwhile, the blocks measuring 25 X 12 X 2 mm
were designed using the same dental design
software mentioned earlier. (Figure 1)
(P=0.000), enquanto para o carregamento à fratura não foi identicada diferença entre grupos (P=0.177).
Houve prevalência de todas as falhas para os grupos 0° e 90° e fratura de retentor para o grupo 45°. Conclusão:
Diferentes angulações de pontes provisórias fabricadas por uma resina impressa 3D promovem impacto sobre a
dureza, contudo não interferem no carregamento à fratura.
PALAVRAS-CHAVE
Angulação; Prótese dentária; Tecnologia digital; Pontes provisórias; Impressão tridimensional.
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
3D printing
The STL le for the specimens was processed
using slicing software (Photon Workshop,
version V2.1.21; Anycubic, Shenzhen, China).
The specimens were then printed using a 3D
printer (Anycubic Photon S Talmax Dental
Prosthesis Printer, Curitiba, Paraná, Brazil)
using the Digital Light Processing (DLP) method.
The printing of the provisional resin specimens
(Resin Bio Prov; Prizma 3D Makertech Labs,
Brazil - composition: Acrylate and Triacrylate
Monomers Proprietary, Amorphous Silica,
Fillers, Meta-Acrylate Oligomers, Diphenyl
(2,4,6-trimethylbenzoyl)) was carried out at
print angles of 0°, 45°, and 90° with a layer
thickness of 0.05 mm, followed by a cleaning
and curing process. After printing, the specimens
were cleaned in isopropyl alcohol for 10 minutes
using an ultrasonic bath and post-cured in a
UV chamber for 10 minutes, according to the
manufacturer’s recommendations. Supports were
removed using a bench motor and diamond disc
cutter. Finally, the t of the specimens on the
metal preparations was veried. (Figure 1)
Experimental groups
The experimental groups were dened by the
printing angle (Table I). The sample size for this
study was calculated using the Minitab statistical
software (version 17 for Windows, Pennsylvania,
USA), based on the standard deviation (27.8)
from a similar study by Turksayar et al. [10] for
fracture loading, resulting in an N=05 with a
sample power of 80.0% concerning maximum
differences. For hardness testing, 05 indentations
were indicated for each block, according to
a similar study by Crenn et al. [2]. Surface
analysis in the study was performed with N=01,
representing one specimen of each type per
experimental group.
Surface analysis
A signicant sample from each experimental
group with each type of specimen (N=1) was
evaluated using Scanning Electron Microscopy
(SEM) (HITACHI, Model TM300) to identify
defects, pores, and the surface behavior of the
material under study.
Figure 1 - A and B - CAD planning; C - DLP printer; D - different printing angles of the provisional bridges, respectively 0°, 45° and 90°; E and
F - bridges positioned on the metal preparation.
Table I - Description of the experimental groups and N sample of the study
Experimental
Group Description
N sample Block
for Surface
Analysis
N sample Fixed
Bridge for
Surface Analysis
N sample Fixed
Bridge
N sample
Indentations for
Hardness (n=block)
0° 0° for printing
angulation N=1 N=1 N=5 N=5
(n=1)
45° 45° for printing
angulation N=1 N=1 N=5 N=5
(n=1)
90° 90° for printing
angulation N=1 N=1 N=5 N=5
(n=1)
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
Hardness
Block specimens underwent 05 measurements
using a Vickers microhardness tester (Micromet
5101, Buehler), under a load of 500 g and a dwell
time of 20 seconds [2]. Five indentations were
made on each specimen near the center, with at
least 0.5 mm spacing. The major diameters of the
Vickers indentations (d1 and d2) were measured
with an optical micrometer, and hardness was
calculated using Formula 1:
( )
1850
1 2
x load
Hardness
d xd
=
(1)
Formula 1: hardness calculation.
Fracture loading test
To measure the fracture force, a compression
test was conducted on the xed bridge. The force
was applied perpendicularly to the central fossa of
the second premolar at a speed of 1 mm/min using
a piston with a 4 mm diameter stainless steel sphere
xed to a testing machine (Emic DL-1000, Emic,
São José dos Pinhais, PR, Brazil) [10]. Maximum
fracture values were obtained in Newtons (N)
for each group. No cementation of the bridges
on the metal preparations was performed for the
test. Additionally, during the test, a 0.5 mm thick
aluminum foil was placed between the pontic and
the piston to avoid peak forces [11].
Fracture analysis
The fractured specimens were analyzed to
determine the characteristics of the fractures.
Failures were categorized based on fractures in
the connector area, pontic, and retainer, presence
of cracks, and all failures occurring together,
following the study by Turksayar et al. [10].
Statistical analysis
Results were tabulated and analyzed using
Minitab (version 17 for Windows, Pennsylvania,
USA), with a signicance level of 5%. The data
for fracture loading and hardness were evaluated
for the effect of printing angle using a 1-Factor
ANOVA test (p<0.05). When differences between
experimental groups were identied, the Tukey
test (p<0.05) was applied to the study data.
The Kolmogorov-Smirnov test was performed to
determine the normality of the data, which was
observed for hardness (p>0.150) and fracture
loading (p>0.150). Surface and fractographic
analyses were evaluated qualitatively.
RESULTS
Based on the analyses conducted, it is
observed that the surfaces of the specimens
with different printing angles exhibit distinct
morphologies, highlighting the characteristics
of the printing layers, especially in the 90° angle
group in the block-type specimen (Figure 2).
Regarding hardness analysis, the 3D printing
angle was statistically signicant among groups
(P=0.000), showing differences across all groups.
The hardness values, in descending order, were
highest at the 90° angle, followed by the 45° and
0° angles (Table II, Figures 3 and 4). From the
perspective of surface analysis of the 3D printed
bridges, a frequency of defects was observed on the
buccal, occlusal, and palatal surfaces in the 0° and
45° groups, attributed to the presence of printing
supports in these areas (Figures 5 and 6). There
Figure 2 - Scanning Electron Microscopy images at 1000X magnification, A - 0°; B - 45°; C - 90°.
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
was also a possible printing defect in the 0° group
resulting in the presence of cracks (Figure 5).
In the 90° group, as the supports are located on
the proximal surface, no damage was recorded
on the provisional bridge on the aforementioned
surfaces (Figure 7). The investigated surfaces of
the provisional bridges are similar in terms of
the arrangement of the printing layers; however,
there is a supercial alteration depending on the
anatomical feature to be printed. Notably, there is
a thicker intermediate layer between the printing
layers in the 45° group (Figure 6), while in other
experimental groups, there is a continuity between
the printing layers. The fracture loading test did
not identify differences between experimental
groups (P=0.177), with the 90° angle group
showing the highest average force supported
before fracture, followed by the 0° and 45° groups
(Table III, Figure 8). Additionally, all types of
failures were prevalent in the 0° and 90° groups,
with retainer fractures observed in the 45° group
(Table IV, Figures 9, 10, and 11).
DISCUSSION
Based on the data obtained from the research,
the null hypothesis—that there would be no
statistically signicant difference concerning the
angulation of 3D-printed resin provisional bridges
in relation to hardness and fracture loading—
Table II - Hardness Data*
Experimental
Groups Mean Standard
Deviation Minimum Maximum P-value
Difference
Between
Groups**
0° 13.34 0.865 12.50 14.30 C
45° 17.56 1.401 16.25 19.20 0.000 B
90° 19.50 1.111 18.45 20.70 A
*Measurements using Vickers microhardness tester (Micromet 5101, Buehler). **Different letters indicate differences between experimental groups.
Figure 3 - Indentations of block specimens, A - 0°; B - 45°; C - 90°.
Figure 4 - Difference between experimental groups for hardness
analysis.
Table III - Fracture Loading Data*
Experimental
Groups Mean Standard
Deviation Minimum Maximum P-value
Difference
Between
Groups**
0° 1101.9 178.1 887.8 1354.2 A
45° 850.0 334 256.0 1046.0 0.177 A
90° 1182.0 284 689.0 1413.0 A
*Test performed using a testing machine (Emic DL-1000, Emic, São José dos Pinhais, PR, Brazil). **Different letters indicate differences between
experimental groups.
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
was partially accepted. This is because the 3D
printing angulation was statistically signicant
with respect to hardness.
Regarding the surface analysis, the distinct
observation of printing layers in the specimens
(geometric and anatomical) was also noted in
Figure 5 - Group 0°, A - bridge with some defects due to support removal on the occlusal surface (6.9X magnification), B and C - occlusal
surface of the first molar (200X and 400X magnification, respectively), D - second premolar with printing failures between the buccal and
occlusal surfaces (50X magnification), and E - cracks and defects on the occlusal surface of the first premolar (200X magnification).
Figure 6 - 45° group, A - bridge with some defects due to removal of the support on the occlusal surface (6.7X magnification), B and C -
occlusal surface of the first molar (200X and 400X magnification, respectively), D - first premolar showing impression layers in the cusp region
(200X magnification), and E - second premolar showing an intermediate layer between the impression layers (400X magnification).
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
other studies, attributed to the DLP printing
technique used in this research, where light is
projected in pixel form onto the printing surface,
polymerizing the resin layer by layer [3,8].
Another observation is that the surfaces of
geometric and anatomical specimens showed
distinct characteristics. When the specimens
were blocks, a heterogeneous surface pattern was
identied among the groups, with the printing
layers being more evident at 90° compared to 0°
and 45°, due to the adopted printing angulation.
The morphologies of these surfaces may
also reflect a different roughness profile,
though this was not measured in this study.
Some studies comparing 3D-printed resin
with conventional resin show varying results.
For instance, Myagmar et al. [5] found that
the 3D-printed resin group presented a
signicantly smoother surface before and after
aging compared to the conventional technique.
Simoneti et al. [4] reported similar surface
Table IV - Fracture Data
Experimental
Group Crack
Fracture Fracture Fracture
All Failures
Retainer Pontic Connector
0° 01 01 - 01 02
45° - 03 02 - -
90° - - - 01 04
Total 01 04 02 02 06
Figure 7 - Group 90°, A - bridge without defects from support removal on the occlusal surface (6.7X magnification), B and C - mesio-buccal
cusp of the first molar (200X and 400X magnification, respectively), D - first premolar showing printing layers on the buccal surface (200X
magnification), and E - occlusal surface of the second premolar (400X magnification).
Figure 8 - Experimental groups for the fracture loading test.
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
roughness data between 3D-printed specimens
and those made using conventional methods.
However, Al-Qahtani et al. [6] found higher
roughness in the 3D-printed sample group, which
could be attributed to material composition or
different printing angles across studies.
Figure 9 - Experimental Group 0°; A - connector fracture, specimen 1; B and C - all failures, specimens 2 and 3, respectively; D - retainer fracture,
specimen 4; E - crack in the connector and pontic region, specimen 5.
Figure 10 - Experimental Group 45°; A - retainer fracture, specimen 1; B - pontic fracture, specimen 2; C - retainer fracture, specimen 3; D -
pontic fracture, specimen 4; E - retainer fracture, specimen 5.
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Braz Dent Sci 2025 Jan/Mar;28 (1): e4581
Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
For geometric specimens, the presence of
various anatomical features might have caused
the surfaces to appear more similar at 0°, 45°,
and 90° angles. This surface condition might
explain the lack of statistical difference between
experimental groups after fracture loading. This
is contrary to Park et al. [12], who suggested that
the surface morphology of a 3D-printed object
could be related to some mechanical properties,
such as exural strength and fracture resistance.
However, that study compared different DLP
printing techniques, stereolithography, and
fused deposition modeling, and did not analyze
angulation as a printing parameter.
Regarding the surface of the bridges, the
presence of supports, especially on the occlusal
face at 0° and 45°, led to the identication of
several anatomical damages on the provisional
bridge. In this study, no nishing or polishing
of the specimens was performed; the tests
were conducted immediately after printing
and support removal. These defects need to be
clinically addressed with nishing and polishing
to prevent bacterial plaque accumulation,
difficulty in occlusal adjustment, or potential
patient harm. At 90°, since the supports are
located on the proximal face, the provisional
bridge’s cementation process is facilitated
with fewer adjustments, reducing clinical
time. Cracks identified at 0° might be due to
the printing orientation, which may limit the
formation of higher anatomical features like
cusps. Additionally, the wide and rough bonding
interface between printing layers at 45° is due
to the printing technique. In DLP, each layer is
formed from a single image displayed on the DMD
chipset, and lines in each layer appear rough due
to the chipset’s resolution limit. In areas where
layer bonding is weak, fractures may occur more
quickly if the surface is rough [12]. This factor
may explain the lower average fracture loading
values in this experimental group.
In this study, printing angulation was a
statistically signicant factor for the hardness of
this material, which is an important nding for the
dental community. The analysis of this variable has
not been previously observed in studies measuring
the hardness of 3D-printed resins for crowns or
provisional bridges. The literature indicates that
the hardness of the resins studied can be affected
by the printing technique [2], composition [2],
printing layer [7], and may show different results
compared to other types of provisional resins [4,6],
with most studies not mentioning printing
angulation in their methodology. Thus, hardness
results may be explained by the testing condition.
Figure 11 - Experimental Group 90°; A - connector fracture, specimen 1; B, C, D, E - all failures, specimens 2, 3, 4, and 5, respectively.
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Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
Even if the specimen is printed in layers with a
90° orientation, the hardness test is conducted
with the specimen in a horizontal position. This
means that there is difculty in indenting directly
between printing layers in the 45° and 90° groups,
thus promoting rupture between them. Therefore,
the 0° group obtained a lower hardness value as
the test was conducted on the specimen’s surface
without directly reaching the printing layers.
A similar scenario was observed in Reymus et al.
[11], where specimens in the distal position
showed a higher fracture load compared to the
occlusal position, due to greater resistance to layer
separation in the direction of the mechanical test
force.
No statistical difference was observed in
fracture loading between the printing angles,
contrary to studies by Reymus et al. [11] and
Turksayar et al. [10]. Post-fracture data may
be explained by the morphological similarity
between specimens. According to Park et al. [12],
the mechanical properties of 3D-printed resins
reect their morphological presentation. Various
commercial resins exhibit different surface
conditions regarding particle size, matrix,
and dimension. Therefore, the morphology
and chemical composition of the resin
influence the mechanical properties of this
temporary material [9]. Aging of specimens
in Turksayar et al. [10] (thermomechanical
with 120000 cycles and baths at 5 - 55°C) and
Reymus et al. [11] (21 days of storage in distilled
water at 37°C) may alter the thicker bonding
layers, resulting in differences in fracture load
values. Additionally, stereolithography’s detail
enhancement, which cannot be replicated with
DLP, and the different chemical composition of
the tested resin contributed to different results
from the current research.
Regarding the fracture pattern, this study
evaluated all specimens after achieving fracture,
meaning the test was not stopped upon identifying
the rst crack. Thus, there was a higher frequency
of all fractures occurring simultaneously in the
specimen, resulting in multiple fragments. This
result supports Park et al. [12] on the fracture of
three-element bridges using the DLP technique,
where the low elasticity of the tested resin
generated multiple fragments, particularly in
the connector area. It is worth noting that the
increasing volume of these fragments may cause
harm to the patient after fracture, due to the
3D-printed resin’s composition based on acrylate
monomers, which has good surface hardness but
is brittle due to its chemical structure. Moreover,
the greater prevalence of all failures in the 0°
and 90° groups can be explained by their ability
to withstand higher loads until fracture, with
greater layer compression and fewer surface
damages, especially in the 90° group. This
contrasts with the conditions observed in the 45°
group regarding average fracture force and the
intermediate layer between printing layers.
The limitations identified in this research
included the lack of aging, comparison of other
printing angles, and additional analyses. Further
studies should investigate fracture loading
after mechanical cycling, identify the origin of
specimen fractures, and perform analyses of elastic
modulus and fracture toughness to gather in vitro
information for subsequent controlled clinical
trials and validate the use of 3D-printed resins for
provisional bridges in daily clinical practice.
CONCLUSION
Based on the results obtained from this in vitro
research, it was observed that different printing
angles for provisional bridges manufactured with
3D-printed resin affect the hardness, but do not
impact the fracture loading.
Author’s Contributions
LMBB: Methodology, Software, Writing -
Original Draft, Formal Analysis, Investigation,
Visualization. YVSS: Formal Analysis, Writing
- Review & Editing. MTLMB: Formal Analysis,
Writing - Review & Editing. TKAS: Formal Analysis,
Writing - Review & Editing. CMLS: Formal
Analysis, Writing - Review & Editing. AJTN: Formal
Analysis, Investigation, Writing - Review & Editing,
Visualization. LALB: Formal Analysis, Investigation,
Writing - Review & Editing, Visualization. VMGF:
Conceptualization, Methodology, Validation,
Supervision, Project Administration.
Conict of Interest
No conicts of interest declared concerning
the publication on this article.
Funding
The authors declare that no nancial support
was received.
11
Braz Dent Sci 2025 Jan/Mar;28 (1): e4581
Batista LMB et al.
Effect of angulation of 3D printed resin provisional bridges: an in vitro study on hardness and fracture loading
Batista LMB et al. Effect of angulation of 3D printed resin provisional bridges: an
in vitro study on hardness and fracture loading
Date submitted: 2024 Nov 19
Accept submission 2025 Mar 08
Antonio José Tôrres Neto
(Corresponding address)
Universidade do Estado de São Paulo, Instituto de Ciência e Tecnologia, São
José dos Campos, SP, Brazil.
Email: ajtn18@gmail.com
Regulatory Statement
None.
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