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.2024.e4503

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

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.

Morphological analysis of the bristles from toothbrushes sold in

the Peruvian market, using scanning electron microscopy

Análise morfológica das cerdas de escovas de dentes vendidas no mercado peruano, utilizando microscopia eletrônica de

varredura

Pablo Alonso LOPEZ BERAUN1 , Edward Antonio ALEGRIA CARHUANAMBO1 , Alberth Jeremias SOTO AMANTE1 ,

Eduardo PAREDES ZELADA1 

1 - Universidad de Huánuco. Huánuco, Huánuco, Peru.

How to cite: Lopez Beraun PA, Alegria Carhuanambo EA, Soto Amante AJ, Paredes Zelada E. Morphological analysis of the bristles

from toothbrushes sold in the Peruvian market, using scanning electron microscopy. Braz Dent Sci. 2024;27(4):e4503. https://doi.

org/10.4322/bds.2024.e4503

ABSTRACT

Objective: To analyze, using scanning electron microscopy, the morphological characteristics of the bristle

laments of toothbrushes marketed in Peru. Material and Methods: Images obtained through scanning electron

microscopy of 23 adult toothbrushes with nylon bristles (621 bristles) were used, and the morphology of their

lament tips was evaluated using the Silverstone and Featherstone classication modied by Reiter and Wetzel

and classied as Acceptable or Non-acceptable. Results: Of the bristles evaluated, 169 (27.2%) were classied as

acceptable, while 452 (72.8%) were non-acceptable. Among the toothbrushes analyzed, four exhibited more than

50% acceptable bristles, including one with 100% acceptability. Conversely, another four brushes displayed 100%

non-acceptable bristles. Conclusion: The results demonstrate a high frequency of non-acceptable bristles, with a

ratio 2.5 times greater than the acceptable ones. This variability indicates a lack of uniformity in manufacturing

standards across brands, emphasizing the urgency to implement stricter regulations to ensure the quality and

safety of these crucial oral hygiene instruments.

KEYWORDS

Dental and oral hygiene products; Oral hygiene; Oral self-care devices; Personal hygiene products; Toothbrushing.

Resumo

Objetivo: Analisar, por meio de microscopia eletrônica de varredura, as características morfológicas dos lamentos

das cerdas de escovas de dentes comercializadas no Peru. Material e Métodos: Foram utilizadas imagens obtidas

por microscopia eletrônica de varredura de 23 escovas de dentes para adultos com cerdas de náilon (621 cerdas),

avaliando-se a morfologia das pontas dos lamentos com base na classicação de Silverstone e Featherstone,

modicada por Reiter e Wetzel, e categorizadas como Aceitáveis ou Não aceitáveis. Resultados: Das cerdas

avaliadas, 169 (27,2%) foram classicadas como aceitáveis, enquanto 452 (72,8%) foram consideradas não

aceitáveis. Entre as escovas analisadas, quatro apresentaram mais de 50% de cerdas aceitáveis, incluindo uma

com 100% de aceitabilidade. Por outro lado, outras quatro escovas apresentaram 100% de cerdas não aceitáveis.

Conclusão: Os resultados demonstram uma alta frequência de cerdas não aceitáveis, com uma proporção 2,5

vezes maior que a de cerdas aceitáveis. Essa variabilidade indica a falta de uniformidade nos padrões de fabricação

entre as marcas, destacando a urgência de implementar regulamentações mais rigorosas para garantir a qualidade

e a segurança desses instrumentos essenciais para a higiene bucal.

PALAVRAS-CHAVE

Dispositivos de autocuidado oral; Higiene bucal; Produtos de higiene dental e oral; Produtos de higiene pessoal;

Escovação dos dentes.

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

INTRODUCTION

Dental caries and periodontal diseases are

highly prevalent pathologies among humans

and are the leading causes of tooth loss. Both

conditions, chronic and complex in nature, share

several risk factors, with the presence of bacterial

plaque being the most notable. This biolm is a

crucial element that poses a signicant threat to

oral health [1-8].

Effective control of biolm, both profession-

ally and personally, is essential to ensure and

maintain oral health, highlighting the removal of

bacterial plaque as a critical strategy in the pre-

vention of oral diseases, using two main methods:

mechanical, such as brushing and ossing, and

chemical, through mouth rinses. Dental hygiene,

particularly through daily and regular toothbrush-

ing, is the most popular and widely adopted

method for this purpose. This approach is the

most important component of prophylaxis against

dental caries and periodontal diseases [3,9-15].

Among the various instruments designed

for oral hygiene, the toothbrush stands out due

to its remarkable efcacy in removing bacterial

plaque, achieving a level of performance that other

devices have not matched [16]. From ancient

Babylon around 3500 BC, where chewing sticks

were used for their antimicrobial properties, to the

invention of the rst toothbrushes with pig bristles

and bamboo or bone handles during the Tang

Dynasty (618-907 AD) in China, the toothbrush

has undergone signicant evolution. These early

designs spread to Europe, where pig bristles were

replaced with softer bristles, such as horsehair, to

suit local preferences. The mass production of the

modern toothbrush began with William Addis in

England in 1780, followed by industrialization

in the United States starting in 1885 [17,18].

The 20th century marked a turning point with

the replacement of bone handles by celluloid

and later other plastics, and the introduction of

nylon bristles and synthetic fibers by DuPont,

which improved the hygiene and durability of

toothbrushes. The innovative design by Dr. Robert

Hutson in the 1950s, featuring multi-tufted nylon

laments with rounded tips and a at cut, known

as the Oral-B manual toothbrush, set a standard

for modern toothbrush design [13,19].

The contemporary market offers a diverse

range of toothbrushes, each claiming superior

plaque reduction capabilities [10], incorporating

design improvements that include the number

and distribution of bristles, as well as the size

and shape of the head, aimed at overcoming

limitations associated with brushing duration and

technique [11,19]. These products are equipped

with unique features, designed to meet precise

standards that facilitate effective dental biolm

management while preserving the integrity of

oral tissues [20].

In the development of new toothbrushes, it

is crucial to assess not only their efcacy in plaque

reduction and improvement of gingival health but

also their safety [19,21,22], which is directly related

to the functional characteristics of the bristles, often

imperceptible to the public, thus necessitating

studies that evaluate this aspect [21,23].

Bristles constitute a critical component of

toothbrushes, being the only part that comes into

direct contact with dental surfaces. For this reason,

a deep understanding of the characteristics of these

components is essential for selecting the appropriate

brush. Factors such as length, diameter, material,

and color of the bristles significantly influence

the brush’s effectiveness in removing plaque and

cleaning teeth effectively [17].

The American Dental Association (ADA)

recommends that bristle tips be rounded

to minimize the risk of dental and gingival

abrasions [12,21,24,25]. In 1988, Silverstone

and Featherstone evaluated the tips of various

toothbrush bristles using a scanning electron

microscope (SEM) and classied them into two

groups: acceptable (nearly rounded) and non-

acceptable (not rounded) [26].

In the toothbrush market, there is a notable

lack of information regarding the rounding of

bristle tips in many available products. This

omission leads to a wide variability in lament

morphology, with tips ranging from completely

rounded to notably sharp [21]. This variability

is also reected in the Peruvian market, where

a wide range of toothbrushes is sold in different

establishments at various prices. Consequently,

the present study aims to analyze, through SEM,

the morphological characteristics of toothbrush

bristle laments marketed in Peru.

MATERIAL AND METHODS

Selection of toothbrushes

This study was conducted at the SEM

Laboratory of the Universidad de Huánuco

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

during the year 2024. Prior to the experiment,

a survey of commercially available toothbrushes

was conducted in various pharmacies, wholesale

stores, and supermarkets in the city of Huánuco.

Nylon toothbrushes with cylindrical laments of

varying stiffness (hard, medium, and soft) were

selected, excluding those with conical bristles that

are chemically treated rather than mechanically

processed. The sample was limited to adult

toothbrushes to reduce variability. After the initial

evaluation, 23 toothbrushes met the established

criteria. One unit of each selected model was

purchased, totaling 621 bristles for analysis. The

details of the models, including toothbrush names,

manufacturers, country of origin, and bristle

stiffness, were documented in Table I, based on

the specications provided by the manufacturers.

Sample preparation

An examiner prepared the samples from

the selected toothbrush brands, assigning

numerical codes to each according to the previous

Table. A tuft was randomly selected from each

toothbrush to cut the filaments using a No.

15 scalpel. To standardize the counting of

laments to be observed, the 10 samples with

the fewest laments per tuft were selected, and

an average was conveniently established across

all observations, resulting in 27 laments (μ =

26.8) selected for each toothbrush brand. The

cut laments were mounted on aluminum slides

using carbon adhesive discs and examined under

a Thermo Scientific Prisma E SEM, operating

under low vacuum conditions at 75 Torr and

30 kV. The microscope was set to a 2 mm

magnication and a 90° viewing angle relative

to the longitudinal axis of the laments.

Analysis of toothbrush lament morphology

Based on the images obtained, the percent-

ages of rounded bristles were evaluated in relation

to the total number of bristles. All determinations

Table I - Distribution of toothbrushes by name and manufacturer

ID Name Manufacturer Bristle

stiﬀness

No. of tufts/

Filaments per tuft Origin

ID_001 Family Care - - 40 / 26 China

ID_002 Pro® Múltiple acción PROCTER & GAMBLE mfg. México Soft 45 / 52 Mexico

ID_003 Pro® Doble acción mayor

alcance PROCTER & GAMBLE mfg. México Medium 50 / 35 Mexico

ID_004 Pro® Doble acción proﬁle PROCTER & GAMBLE mfg. México Hard 50 / 18 Mexico

ID_005 Oral B® Pro-Salud 4 beneﬁcios PROCTER & GAMBLE mfg. México Soft 38 / 32 Mexico

ID_006 Colgate® Extra clean COLGATE SANXIAO Co. Hard 43 /16 China

ID_007 Colgate® Extra clean COLGATE SANXIAO Co. Medium 43 / 36 China

ID_008 Connert Djimba - Soft 35 / 34 -

ID_009 Colgate® Premier Clean COLGATE PALMOLIVE Medium 38 / 42 Vietnam

ID_010 New biofresh - Soft 42 / 28 China

ID_011 Kolynos® Master Plus COLGATE SANXIAO Co. Medium 39 / 32 China

ID_012 Dento® INTRADEVCO INDUSTRIAL Medium 40 / 24 Peru

ID_013 Oral B® 1,2,3 RIALTO ENTERPRISES PVT. Ltda Medium 38 / 50 China

ID_014 Vitis® Medio DENTAID S.L. Medium 29 / 35 Spain

ID_015 Vitis® Suave DENTAID S.L. Soft 29 / 42 Spain

ID_016 Vitis® Duro DENTAID S.L. Hard 40 / 30 Spain

ID_017 Colgate® 360° Advanced

Luminous COLGATE SANXIAO Co. Soft 26 / 52 China

ID_018 Balanzé BÁSICOS PROACTIVE HUBEI CROWN HOUSEWARES Co.

Ltd Medium 37 / 30 China

ID_019 Oral B® Pro-Salud 7 beneﬁcios RIALTO ENTERPRISES PVT. Ltda Soft 35 / 72 India

ID_020 Oral B® Complete 4 beneﬁcios PROCTER & GAMBLE mfg. México Medium 38 / 42 Mexico

ID_021 Daily Caristop® MAVER PERÚ S.A.C. Soft 41 / 50 Peru

ID_022 Colgate® Recy Clean COLGATE SANXIAO Co. Soft 39 / 45 China

ID_023 Total Dent - n.s. 41 / 32 China

n.s. = …

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

of the rounding patterns of toothbrush bristles

were performed by two blind, duly calibrated

investigators. To mitigate the risk of bias related to

the prior knowledge of the toothbrush brands by

the investigators responsible for sample prepara-

tion, rigorous measures were adopted to ensure

the impartiality of the analysis. The samples

were exclusively evaluated by two independent

researchers who did not participate in the prepara-

tion phase or in the capture of images using SEM.

This strategy ensured complete blinding of the

evaluators, avoiding any inuence derived from

familiarity with the toothbrush brands.

For the evaluation of the bristle tip

morphology, the Silverstone and Featherstone

classification [26], modified by Reiter and

Wetzel [27], was used, as shown in Figure 1,

taken from the study by Lee et al. [23]. In this

classication, bristles with adequately rounded

ends were considered acceptable and were

subdivided into three categories (A1–A3).

On the other hand, bristles with undesirable

characteristics, such as sharp edges, sharp

rectangular tips, sharp oblique tips, triangular tips,

and tips with protruding plastic material, were

classied as non-acceptable. These were further

grouped into ve subcategories (N1–N5) [23].

Due to the microscope’s magnification

settings, it was necessary to capture multiple views

to observe the 27 laments for each brush ID.

Analysis of the obtained data

After data collection, the cumulative

frequency distribution by characteristics and

pattern type was analyzed according to the

Silverstone and Featherstone classication [26],

modied by Reiter and Wetzel [27]. Subsequently,

the ratio between the total bristles per pattern

and the total number of bristles in the study was

calculated to determine the relative frequency of

the characteristics and pattern types of the bristles

for each toothbrush ID.

RESULTS

The characteristics of the bristles of the

toothbrushes evaluated in this study are shown in

Table II. According to the total number of bristles

analyzed by SEM (n=621), it was observed

that the number of acceptable bristles was 169

(27.2%). Of the total toothbrushes analyzed,

only four codes (ID 001, 002, 006, and 023)

had a percentage of over 50% acceptable bristles

based on the number of laments per sample.

Additionally, four codes (ID 010, 011, 012, and

022) were observed with a 100% percentage

of non-acceptable bristles. The remaining

observations ranged from 7.4% to 48.1% for

acceptable bristles. ID 002 had an observation

equal to 100% acceptable bristles.

On the other hand, Table III shows the

distribution of bristle characteristics by pattern

type according to the classication of Silverstone

and Featherstone [26], modified by Reiter

and Wetzel [27]. In the case of patterns with

Acceptable tips, ordered from highest to lowest,

category A3 presented a percentage of 12.6%,

followed by A1 with 8.4% and A2 with 6.3%.

Figure 1 - Classiﬁcation of toothbrush bristle tip morphology according to Silverstone and Featherstone [26], modiﬁed by Reiter and Wetzel [27].

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

Table II - Distribution of bristle characteristics according to SEM observation

ID Acceptable % Non-Acceptable % Total bristles

per tuft %

ID_001 19 70.4% 8 29.6% 27 4.3%

ID_002 27 100.0% 0 0.0% 27 4.3%

ID_003 11 40.7% 16 59.3% 27 4.3%

ID_004 4 14.8% 23 85.2% 27 4.3%

ID_005 5 18.5% 22 81.5% 27 4.3%

ID_006 18 66.7% 9 33.3% 27 4.3%

ID_007 6 22.2% 21 77.8% 27 4.3%

ID_008 3 11.1% 24 88.9% 27 4.3%

ID_009 5 18.5% 22 81.5% 27 4.3%

ID_010 0 0.0% 27 100.0% 27 4.3%

ID_011 0 0.0% 27 100.0% 27 4.3%

ID_012 0 0.0% 27 100.0% 27 4.3%

ID_013 3 11.1% 24 88.9% 27 4.3%

ID_014 8 29.6% 19 70.4% 27 4.3%

ID_015 4 14.8% 23 85.2% 27 4.3%

ID_016 4 14.8% 23 85.2% 27 4.3%

ID_017 10 37.0% 17 63.0% 27 4.3%

ID_018 13 48.1% 14 51.9% 27 4.3%

ID_019 7 25.9% 20 74.1% 27 4.3%

ID_020 2 7.4% 25 92.6% 27 4.3%

ID_021 5 18.5% 22 81.5% 27 4.3%

ID_022 0 0.0% 27 100.0% 27 4.3%

ID_023 15 55.6% 12 44.4% 27 4.3%

Total 169 27.2% 452 72.8% 621 100%

Table III - Distribution of bristles by pattern type

ID Acceptable Non-Acceptable Number of bristles analyzed %

A1 A2 A3 N1 N2 N3 N4 N5

D_001 7 - 12 - 4 4 - - 27 4.30%

ID_002 3 6 18 - - - - - 27 4.30%

ID_003 - 4 7 - 9 7 - - 27 4.30%

ID_004 1 3 - - 23 - - - 27 4.30%

ID_005 5 - - 3 19 - - - 27 4.30%

ID_006 - - 18 - 8 1 - - 27 4.30%

D_007 - - 6 - 4 17 - - 27 4.30%

ID_008 - 3 - 5 - - 9 10 27 4.30%

ID_009 - - 5 - 5 17 - - 27 4.30%

ID_010 - - - 2 7 - 18 - 27 4.30%

ID_011 - - - - 17 10 - - 27 4.30%

ID_012 - - - 2 9 16 - - 27 4.30%

ID_013 1 2 - 1 7 5 5 6 27 4.30%

ID_014 8 - - 4 12 3 - - 27 4.30%

ID_015 4 - - 9 10 3 - 1 27 4.30%

ID_016 1 3 - - 11 12 - - 27 4.30%

ID_017 3 7 - 9 2 - 6 - 27 4.30%

ID_018 7 2 4 9 1 4 - - 27 4.30%

ID_019 2 2 3 3 11 5 1 - 27 4.30%

ID_020 - - 2 9 11 5 - - 27 4.30%

ID_021 5 - - 7 9 4 2 - 27 4.30%

ID_022 - - - 6 - 21 - - 27 4.30%

ID_024 5 7 3 1 3 8 - - 27 4.30%

Subtotal 52 39 78 70 182 142 41 17 621 100%

fr (%) 8.40% 6.30% 12.60% 11.30% 29.30% 22.90% 6.60% 2.70% 1215 100%

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

Likewise, in the Non-Acceptable pattern group,

the category that presented the highest frequency

was N2 with 29.3%, followed by N3, N1, N4, and

N5 with frequencies of 22.9%, 11.3%, 6.6%, and

2.7%, respectively.

Figure 2 presents SEM images showing the

tips of toothbrush bristles. Images labeled I and

II represent bristles classied within acceptable

quality standards. In contrast, images labeled

III and IV show bristles that do not meet the

established quality criteria and are considered

non-acceptable.

DISCUSSION

The purpose of this study was to analyze,

through SEM, the morphological characteristics

of the bristle laments from toothbrushes sold in

the Peruvian market.

Good oral hygiene practiced regularly can

help maintain functional dentition throughout

life. However, it is also known that good oral

hygiene standards have often been associated

with soft tissue complications, such as

gingival abrasions [1,10,19,28,29], which are

characterized as localized, reversible epithelial

lesions that can range from supercial wounds

to erosions exposing the underlying connective

tissue. This complication can be caused by

various factors, including excessive use of the

toothbrush, brush design, bristle stiffness and

quality, as well as brushing frequency and the

characteristics of the bristle material [21].

Specically, the use of brushes with non-rounded

lament tips has been linked to a higher incidence

of these lesions [12,21,24,25]. Hennequin‐

Hoenderdos et al. [21] have demonstrated that

a rounding of bristle tips between 40% and

50% can signicantly reduce the risk of gingival

abrasions. It has been emphasized that repeated

gingival abrasions constitute a signicant factor

in the development of gingival recession [1,30].

However, there is no clear evidence that gingival

abrasion caused by toothbrushing leads to

recession [1], as the etiology of gingival recession

is multifactorial, involving anatomical and

iatrogenic factors, in addition to pathological

conditions associated with dental plaque, such

as periodontitis [28].

Figure 2 - SEM images showing the tips of toothbrush bristles. Images labeled I and II were classiﬁed as acceptable, while labels III and IV

correspond to bristles considered non-acceptable.

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

The ADA also mentions dental abrasions

as a pathology that can be prevented by using

toothbrushes with rounded bristles [12,21,24,25].

These non-carious lesions are common among

patients who suffer from dental sensitivity and

discomfort resulting from dentin exposure [31],

and are associated with gingival recession [1].

However, it has been established that nylon

toothbrushes alone have insignificant effects

on hard dental tissues and could only indirectly

inuence the abrasion process by modulating the

action of toothpaste abrasives carried over the

dental surface, which varies depending on the

design of each brush [32].

According to the guidelines of the “European

Workshop on Mechanical Plaque Control,”

the optimal toothbrush should be tailored to

the user’s individual needs. It is essential that

the brush head is proportionate to the oral

cavity of the person using it, considering their

age and motor skills. Moreover, the brush

laments should be soft and comply with ISO

standards, with materials such as nylon or

polyester being preferred. These laments should

have rounded ends to prevent injuries to the gums

and soft tissues, and their diameter should not

exceed 0.25 mm to facilitate effective and safe

brushing [12,24]. It is crucial that the proportion

of bristles with an acceptable morphology exceeds

those considered non-acceptable according to

Silverstone and Featherstone’s denition [12].

A wide range of toothbrushes shows

variability in the degree of bristle tip rounding,

and a signicant percentage of these do not meet

acceptable quality standards [21]. The results of

the present study revealed a notable variability

in the quality of the analyzed toothbrushes,

with some samples presenting 100% non-

acceptable bristles, while others exhibited

entirely acceptable bristles. This heterogeneity

is consistent with ndings reported in previous

literature, reflecting the variability among

different brands and models. Rehman et al. [10]

found that between 57.6% and 91.7% of the

bristles met the acceptability criteria, whereas

studies like that of Yildiz Telatar et al. [12]

reported lower compliance percentages, ranging

from 8.9% to 41.3%. These differences may be

inuenced by variability in toothbrush design

and manufacturing processes used by different

producers. Additionally, Lee et al. [23] observed

even lower percentages of acceptable bristles

(1.4% to 20.2%) in children’s toothbrushes,

which is particularly concerning given that

children are more vulnerable to harm caused

by poorly designed bristles. On the other hand,

Jung et al. [29] identified greater variability

in children’s electric toothbrushes, with an

acceptability percentage ranging from 18.9% to

94.3%; for adult toothbrushes, they found that

between 21.7% and over 80% of the bristles

were acceptable. This suggests that electric

toothbrushes also suffer from inconsistencies

in quality standards. These findings align

with those of Meyer‐Lueckel et al. [33] and

Checchi et al. [24], who reported a wide variation

in bristle quality (34% to 98% and 0% to

70%, respectively). The results of this research

contribute to the growing body of evidence

highlighting inconsistencies in toothbrush

manufacturing standards. This underscores the

need for more rigorous regulations at both local

and global levels to ensure the quality and safety

of these essential products.

Studies that evaluate the morphology of

bristle tips are generally conducted using optical

microscopy, stereomicroscopy, or SEM [12,29,33].

The latter method is preferred due to its high

resolution, which facilitates detailed visualization

of bristle tips. The SEM’s ability to capture

images with superior depth of focus allows the

researcher to discern variations in the surface

texture of multiple filaments within a single

tuft simultaneously [33]. Consequently, this

study used images from SEM to achieve precise

representations of the laments. However, it is

important to consider that the three-dimensional

representation of a lament tip is reduced to a

two-dimensional image in the capture process,

limiting the analysis to only the visible parts of

the lament tip, omitting any hidden aspects.

As a result, some judgments or measurements

may be erroneously positive, following the

evaluation instrument proposed by Silverstone

and Featherstone [33].

Another limitation identified in research

related to SEM is the potential morphological

alteration of toothbrush bristle tips. These

changes are attributed to temperature increases

during preparatory procedures for analysis,

which can signicantly compromise the integrity

of the samples and, consequently, affect the

reliability of the results obtained [23,29].

Franchi and Checchi [34], in a study, revealed

that the preparatory conditions for analyzing

toothbrush bristles using SEM affect their original

Braz Dent Sci 2024 Oct/Dec;27 (4): e4503

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

morphology. Factors such as the distance to the

cathode in a sputter coater and the coating time

with gold-palladium inuence the temperature

within the vacuum chamber, which in turn

modies the morphology of the bristles. They

found that higher temperatures, around 59 °C,

near the cathode can alter the shapes of the

bristles, making them appear acceptable when

they are not, while lower temperatures, around

38 °C, tend to preserve their original shape.

This is why some of the studies mentioned

in the previous paragraph opted to use the

stereomicroscope [12,24]. In the present study,

a low-vacuum SEM method was used, where

the aforementioned preliminary coating was

not necessary, maintaining the integrity of the

laments throughout the process.

A signicant limitation of the present study

was the use of a single tuft per toothbrush,

selected at random. This methodology did not

allow for determining whether variations exist

between individual tufts or among different

toothbrushes of the same model. Therefore, it is

recommended that future research include the

evaluation of multiple toothbrushes per brand to

obtain more generalizable and accurate results.

CONCLUSIONS

The Comparative observation between

acceptable and non-acceptable bristles revealed

that the prevalence of non-acceptable bristles was

signicantly higher, surpassing the acceptable

ones by a ratio of 2.5 to 1.

Author’s Contributions

PALB: Conceptualization, Investigation,

Writing – Original Draft Preparation, Writing –

Review & Editing, Project Administration, Funding

Acquisition. EAAC: Investigation, Writing – Original

Draft Preparation, Writing – Review & Editing.

AJSA: Writing – Original Draft Preparation, Writing

– Review & Editing. EPZ: Conceptualization,

Investigation, Writing – Original Draft Preparation,

Writing – Review & Editing.

Conict of Interest

The authors have no personal, nancial, or

proprietary interests in any product, service, and/

or company presented in this article.

Funding

This study was fully funded by the

Universidad de Huánuco, under Resolution No.

857-2023-P-CD-UDH.

Regulatory Statement

This study was exempted from review by the

local ethics committee, since it did not involve

the participation of any volunteers, or the use of

any human material.

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Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold in the Peruvian market, using scanning electron microscopy

Lopez Beraun PA et al. Morphological analysis of the bristles from toothbrushes sold

in the Peruvian market, using scanning electron microscopy

Date submitted: 2024 Aug 30

Accept submission: 2024 Nov 21

Pablo Alonso Lopez Beraun

(Corresponding address)

Universidad de Huánuco, Huánuco, Huánuco, Peru

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