Invest Clin 65(3): 378 - 386, 2024 https://doi.org/10.54817/IC.v65n3a10

Corresponding author: Sergio Duarte-Inguanzo. Privada Los Pinos No. 7, Colonia Cañada de la Bufa, Guadalupe,

Zacatecas, México. Zip Code: 98619. México. Phone: +52-492-9229924. Email: sergio.duarteinguanzo@hotmail.com

Prediction of the individual response

to treatment of skeletal Class III

malocclusions and their long-term stability.

A Case Report.

Sergio Duarte-Inguanzo1, 2, Aurora Duarte-López3, Olga Zambrano 4

y Jesús A. Luengo-Fereira5

1 Unidad Académica de Odontología, Universidad Autónoma de Zacatecas, Ciudad

de Zacatecas, México.

2 División de Estudios para Graduados, Facultad de Odontología, Universidad del Zulia.

Maracaibo, Venezuela.

3 Facultad de Odontología Unidad Saltillo, Maestría en Ortodoncia, Universidad

Autónoma de Coahuila, México.

4 Instituto de Investigaciones, Facultad de Odontología, Universidad del Zulia.

Maracaibo, Venezuela.

5 Unidad Académica de Odontología, Universidad Autónoma de Zacatecas, Ciudad

de Zacatecas, México.

Key words: Class III; facial mask; craniofacial growth.

Abstract. Predicting the outcome of the treatment and its stability over

time is an invaluable tool for the clinician when initiating therapy for correction

of class III skeletal malocclusions. This work reports the predicted response to

treatment of a 5-year-old female patient with skeletal Class III malocclusion and

its long-term stability. The individual prediction cephalometric model of Baccetti

and Franchi was applied in this case. As a result of the predictive equation, an in-

dividual value of -0.958 was obtained (norm = -0.4065), which predicted a “very

good response to treatment”. The Class III malocclusion and anterior crossbite

were corrected, and the profile was harmonized with rapid maxillary expansion

(RME) and a facemask projecting the maxilla forward 12 mm, in addition to the

mandible’s 9° total downward rotation. After 15 years and three months of com-

pleting the treatment, the stability of the results was confirmed. In conclusion,

the individual prediction cephalometric model used in this case report allowed

us to accurately predict the results in facial, skeletal and dental changes and the

long-term stability of the treatment of class III skeletal malocclusion.

Response to treatment of skeletal Class III malocclusions 379

Vol. 65(3): 378 - 386, 2024

Predicción de la respuesta al tratamiento de las maloclusiones

clase III esqueléticas y su estabilidad a largo plazo.

Presentación de un caso.

Invest Clin 2024; 65 (3): 378 – 386

Palabras clave: Clase III; máscara facial; crecimiento craneofacial.

Resumen. Predecir el resultado del tratamiento y su estabilidad en el

tiempo es una herramienta invaluable para el clínico al iniciar una terapia para

la corrección de las maloclusiones esqueléticas clase III. Este trabajo reporta

los hallazgos de la predicción de la respuesta al tratamiento y su estabilidad a

largo plazo en una paciente femenina de 5 años de edad con maloclusión Clase

III esquelética. Se aplicó el modelo cefalométrico de predicción individual de

Baccetti y Franchi y se obtuvo como resultado de la ecuación predictiva un valor

individual de -0.958 (norma= -0.4065), lo cual predijo una “muy buena res-

puesta al tratamiento”. Se corrigió la maloclusión Clase III, la mordida cruzada

anterior y se armonizó el perfil con expansión rápida maxilar (ERM) y una más-

cara facial mediante la proyección de la maxila 12 mm hacia adelante, además

de la rotación descendente total de la mandíbula 9°. Después de 15 años y 3

meses de finalizado el tratamiento se confirmó la estabilidad de los resultados.

En conclusión, el modelo cefalométrico de predicción individual utilizado en

este reporte de caso permitió predecir de manera acertada los resultados en

los cambios faciales, esqueletales y dentales y la estabilidad a largo plazo del

tratamiento de la maloclusión esquelética clase III.

Received: 28-01-2024 Accepted: 13-05-2024

INTRODUCTION

Class III skeletal malocclusion, due to

its characteristics, gives a hard aspect and

the appearance of a severe and rigid person.

In fact, in comics, bad guys are attributed

a profile of this type. However, these maloc-

clusions are generally easy to diagnose and

treat in growth-development patients. It is

common for parents to notice them by their

appearance alone; that is, class III is evident

and is also friendly in its therapeutic re-

sponse in most cases 1.

They can present with alterations in

various structures 2. however, relapse is a

phenomenon that develops frequently. To be

considered a successful therapy, good results

need to be maintained in the long term. The

response to treatment and its stability vary

from patient to patient, so some patients are

predestined to orthopedic failure and surgi-

cal treatment in adulthood 3-5.

The facemask is one of the most effec-

tive orthopedic therapies. However, failure

can occur even in correctly applied treat-

ments and with cooperative patients in some

cases, generating frustration in the patient

and the clinician 6. This context places the

dentist at a disadvantage; there is a need to

know when to start the treatment, which cas-

es will be corrected successfully and which

will not, the conditions that determine good

results, and their long-term stability. Saa-

dia M. affirms that if the therapy is applied

380 Duarte-Inguanzo et al.

Investigación Clínica 65(3): 2024

when the biological events occur during the

growth and craniofacial development pro-

cess (during the primary and early mixed

dentitions), it will have a more effective im-

pact and have less tendency to relapse7. The

authors Zere et al. and Campbell state that

applying these treatments in the prepuber-

tal stage is necessary 8,9. Tweed described

two different patterns of Class III malocclu-

sion that predict the outcome of the treat-

ment: a favorable pattern characterized by

hypodivergent growth and an unfavorable

pattern characterized by hyperdivergent

growth 10. Wendl et al. analyzed differences

between patients with Class III malocclusion

treated with success or failure, finding that

an increased maxillary intermolar width has

a higher risk of recurrence and treatment

failure 11. Paoloni et al. report that the width

of the dental arch and the length of the up-

per sagittal arch in primary dentition are

predictors of prognosis; when the length of

the arch is decreased and the intermolar di-

mension is increased, there will be a greater

risk of recurrence 12. Thamira et al. and Zent-

ner et al. reported that the gonial angle, ra-

mus dimensions, and the mandibular body

were determining factors between those who

responded well or poorly to Class III treat-

ment. The treatments were done with com-

monly used fixed and removable devices and

combinations. An evaluation of the retention

of the results was not provided 13,14. Björk re-

ports that a closed angulation of the skull

base in patients with class III malocclusion

is an unfavorable condition in the prognosis

of long-term treatment 15.

Some cephalometric indicators predict

treatment prognosis based on different vari-

ables, achieving different confidence levels.

The most frequently studied variables are

the gonial angle, Witts assessment, ramus

length, the inclination of the lower incisors

with respect to the mandibular plane, and

the SNB angle 11,16.

Baccetti and Franchi proposed a model

of cephalometric variables that individually

predicts the response to treatment of skele-

tal Class III malocclusions treated with rapid

maxillary expansion (RME) and facemask17.

This predictive model is based on three

cephalometric measurements: the vertical

length of the mandibular ramus (Co-Go),

the skull base angle (Ba-T and SBL), and the

angle of the mandibular plane and cranial

base (PM-SBL). When applying the results

of these cephalometric measurements to an

equation generated with the multivariate

statistical method at the beginning of treat-

ment, an individual value is obtained, which,

when compared to the established norm

(-0.4065), can predict the degree of thera-

peutic success or failure 17 (Fig. 1).

The present work describes the findings

of the prediction of the response to treat-

ment with rapid expansion and facial mask

of a skeletal Class III malocclusion and its

long-term stability using the Baccetti and

Franchi predictive method 17.

CASE PRESENTATION

This is the case report of a 5-year-old

female patient who attended the orthodon-

tic service at the Piezzo Clinic in Zacatecas,

Mexico. After explaining the study’s pur-

pose, her parents signed a consent form and

approved the publication of her photographs

in this paper.

The patient presented no medical his-

tory of interest, with an euryprosopic, sym-

metrical, and levelled facial type. She had a

slightly decreased lower third, concave profile

with an evident anteroposterior deficiency in

the middle third and an increased chin-neck

distance (Fig. 2a). The patient had primary

dentition with the absence of dental organ

51, physiological spaces present, a -6mm se-

vere anterior crossbite, bilateral edge-to-edge

posterior occlusion, exaggerated or severe

mesial step, bilateral class III canine relation-

ship, and 0% overbite. (Fig. 3a).

The cephalometric analysis 18 revealed

a concave skeletal Class III profile with max-

illary retroposition and mandibular upward

rotation (Fig. 4a).

Response to treatment of skeletal Class III malocclusions 381

Vol. 65(3): 378 - 386, 2024

When calculating the predictive value

of the Baccetti and Franchi model for Class

III, the result was –0.958. According to this

indicator, the patient would have “a great re-

sponse” to the treatment 17 (Fig. 5).

The patient was treated with rapid

maxillary expansion (RME) using a fixed

Hyrax-type expander for three weeks, with

daily activation, and maxillary protraction

therapy with a facemask, starting at cervi-

Fig. 1. (Procedure): Cephalometric Measurements of the predictive model of Baccetti and Franchi, and pre-

dictive model equation and critical value.

Fig. 2. Front and profile photographs: Initial, five years-seven months old (2a), four months after starting maxil-

lary protraction, five years 11 months old (2b), end of orthopedic treatment, nine years 11 months old

age (2c), facial characteristics 15 years three months post-treatment, 25 years two months old (2d).

382 Duarte-Inguanzo et al.

Investigación Clínica 65(3): 2024

cal maturation stage SC1 19, at five years and

seven months of age, with constant use of 16

hours a day for a year, positive results were

manifested from the first four months (Figs.

2b and 3b). She then continued using the

facemask occasionally for periods of three

months, with a break of approximately eight

months to control relapse until the end of

the maxillary growth peak, cervical matura-

tion stage SC3 19 and ending at nine years 11

months, with a total treatment time of four

years and four months. A straight, harmoni-

ous, and proportionate profile was obtained

(Fig. 2c), achieving a bilateral Class I molar

and canine relationship and a positive over-

bite of 2 mm (Fig. 3c).

The post-treatment cephalometry 18

quantified the improvement in the charac-

teristics of the skeletal profile. The most

notable being the 9° forward relocation of

the maxilla, as well as the relocation of the

chin backward, due to the sum of the down-

ward rotations between ramus and body, 4°

the mandibular arch, and 9° the mandibular

plane. At the end of this orthopedic phase,

the patient was nine years and 11 months

old (Figs. 2c, 3c, and 4b). The parents were

satisfied with this result and decided not to

proceed with a second multibracket phase

for the final correcting details.

New records were taken when the pa-

tient was 25 years old. A symmetrical face was

observed with properly proportioned thirds, a

harmonious contour, and a straight and bal-

anced profile (Fig. 2d). Intraorally, the overjet

and overbite remained stable. Likewise, in an

anteroposterior direction, the class I molar

relationship and the bilateral class I canine

relationship achieved at the end of treatment

were maintained without recurrence up to

the end of the follow-up period. The anterior

lower spaces were maintained, while the up-

per ones were closed (Fig. 3d).

In cephalometry 18, relevant changes

were the increases in maxillary height and

AFAI that combined with a stable maxillary

depth (91°) and the increase in the measure-

ment of the mandibular arch (4°) in the 15

years after completing the treatment (Fig.

4c). They further improved the balance and

Fig. 3. Intraoral photographs: Initial, five years seven months of age (3a), four months after beginning maxillary

protraction, five years 11 months of age (3b), end of orthopedic treatment, nine years 11 months of

age (3c), occlusal characteristics, 15 years three months post-treatment, 25 years two months old (3d).

Response to treatment of skeletal Class III malocclusions 383

Vol. 65(3): 378 - 386, 2024

Cephalometric

Measurement

Norma / Patient

pretreatment (4a)

Norma / Patient

Ends of orthopedic (4b)

Norma / Patient

15.3 years

posttreatment(4c)

Convexity 2mm/ -7mm 2mm/ 5mm 2mm/3mm

Maxillary depth 90° / 83° 90° / 92° 90° / 91°

Facial depth 87° / 89° 87° / 86° 87° / 88°

Mandibular body length 61mm / 60 mm 65mm / 64 mm 69 / 70 mm

Mandibular plane 26° / 19° 26° / 28° 26° / 27°

Maxillary height 51° / 44° 53° / 54° 57° / 58°

Lower Anterior Facial Height (LAFH) 47° / 41° 47° / 48° 47° / 50°

1 upper/ N-A 22° / 21° 22° / 23° 22° / 23 °

1 lower / N-B 25° / 24° 25° / 25° 25° / 25°

Mandibular arch 26° / 31° 26° / 27° 28.5° / 31°

Cranial deflection 27°/ 24° 27°/ 24° 27°/ 24°

Posterior facial height 55mm/ 51mm 56.4mm/ 54mm 58.5mm/ 57mm

4a 4b 4c

Fig. 4. Cephalometric analysis: Initial at five years seven months of age (4a). End phase 1, at nine years 11

months of age (4b). Measurements at 25 years two months of age (4c).

Fig. 5. Application of the individual prediction model at the beginning of treatment. According to this result,

it would have a great response and stability.

384 Duarte-Inguanzo et al.

Investigación Clínica 65(3): 2024

symmetry in the profile and the lower third,

adjusting with the self-consolidation of the

permanent dentition (Fig. 3d).

DISCUSSION

Skeletal Class III treatments in chil-

dren are very rewarding because they are

imposing on most patients. However, there

are some cases that, due to their character-

istics, require surgical treatment when they

reach adulthood 1.

The Baccetti and Franchi cephalomet-

ric prediction model for Class III identifies

three variables with a predictive power of

83.3% reliability 17. Orthopedic treatment

will be unfavorable when there is: a) an acute

angle of the skull base (Ba- T and the SBL),

b) an open angle between the mandibular

plane and the cranial base (PM-SBL), and c)

a long mandibular ramus (Co-Goi) 17, (Fig.

1). It is worth mentioning that these au-

thors only included the stability results after

a follow-up of six years post-treatment. In

the present case report, this model correctly

predicted the favorable response to treat-

ment after 15 years.

In skeletal Class III, the therapeutic

solution is based mainly on the anterior

repositioning of the maxilla and downward

mandibular rotation, thus increasing the an-

terior inferior facial height (AFAI) 4. West-

wood et al. states that all orthopedic force is

more effective when applied in the same di-

rection of displacement due to bone growth

6. By nature, the direction of displacement

during the growth of the upper jaw is for-

ward and downward (perpendicular to the

anterior cranial base) 20. So, if the anterior

cranial base presents an inclination upwards

(open skull base angle), we will have a bet-

ter response to the orthopedic maxillary pro-

traction. Furthermore, if the mandible has

a counterclockwise rotation (closed man-

dibular plane angle) and a vertically short

ramus, there will be a better response to the

effect of the facial mask, thus obtaining a

straighter profile and a more proportionate

and balanced face and vice versa 6. These

considerations give meaning to the cephalo-

metric measurements of the predictive mod-

el of Baccetti and Franchi since they evalu-

ate precisely these variables. In addition,

they include structures governed by genet-

ics, such as the skull base, and others that

can be modified by the environment, such as

the maxilla and mandible 21, which makes it

more systematic and distinguishes it from

the others. This statement coincides with

that of Batagel 2 and Björk 15, who report

that a closed angulation of the skull base is

an unfavorable condition in the prognosis of

long-term treatment. The patient presented

an open cranial base angulation in this re-

port.

The other two variables analyzed by this

prediction model are the vertical length of the

ramus and the mandibular rotation through

the distance from Co to Goi and the angle

between the mandibular plane (PM) and the

skull base (SBL), respectively. A short verti-

cal ramus and a decreased mandibular plane

angle may indicate a lack of vertical growth

in the middle and lower third of the face 18.

So, if these measurements within the pre-

dictive equation result in a figure below the

critical value or norm, it will be reasonable

that the response is good since protraction

therapy will cause downward rotation of the

jaw, increasing the vertical and generating a

straighter profile and a better proportion in

the dimensions of the face.

Tweed and Nardoni et al. report that

the hypo-divergent facial growth pattern

predicts success, and the hyper-divergent

pattern predicts treatment failure 10,16. This

conclusion is reasonable since one of the ef-

fects generated by the biomechanics of fa-

cial mask therapy is the downward rotation

of the jaw, thus increasing the facial vertical.

The patient presented in this work had a hy-

po-divergent facial pattern. The importance

of vertical skeletal relationships in determin-

ing the prognosis of early treatment of Class

III malocclusions has also been emphasized

by Franchi et al. 22, who found that patients

Response to treatment of skeletal Class III malocclusions 385

Vol. 65(3): 378 - 386, 2024

with a large angle between the mandibular

and palatal planes in the primary dentition

ended up with less favorable long-term re-

sults. Tahmina et al. and Zentner et al. agree

with this predictive cephalometric model re-

garding the height of the mandibular ramus

since they also identified the height of the

ramus and the dimensions of the mandibu-

lar body as discriminating factors between

those who responded well or poorly to the

treatment 13,14. The patient in this report had

decreased posterior facial height and a verti-

cally short ramus.

Some research has reported other types

of predictive variables based on the dimen-

sions of the dental arches. Paoloni et al. and

Franchi et al. report that the width of the

dental arch and the length of the upper sag-

ittal arch in primary dentition are predictors

of prognosis. When the arch length decreas-

es and the inter-molar dimension increases,

there will be a greater risk of recurrence 12,22.

In the present case, the patient had prima-

ry dentition at the beginning of the treat-

ment; the transverse dimension of the upper

arch was decreased, with an adequate arch

length. Hence, the excellent treatment re-

sults and long-term stability coincided with

the findings of these authors 12,22. In the pres-

ent case, the structural characteristics were

corrected with the treatment and generated

self-improvement and stability of long-term

results, which was considered a successful

treatment. Surprisingly, in this patient, 15

years and three months after treatment,

her clinical and cephalometric records still

showed specific favorable self-regulated

changes, which allows us to think that in

some skeletal Class III malocclusions, cra-

niofacial growth and development are capa-

ble of improving on its own. Their conditions

exceeded our expectations.

In conclusion, the individual prediction

cephalometric model of the authors Bac-

cetti and Franchi for Class III malocclusion,

applied in the present report, predicted the

success of the treatment of this particular

patient and could be confirmed not only

with the results in the facial-skeletal and

dental changes but also with its long-term

stability within the 15 years post-treatment

follow-up.

ACKNOWLEDGMENT

We thank Dr. Humberto Martínez for his

contribution to editing and translating the

manuscript and Carlos E. Duarte-Hernández

for searching bibliographic references.

Funding

This study was not funded.

Conflicts of interest

The authors reported no potential con-

flict of interest.

Authors’ ORCID number

• Sergio Duarte-Inguanzo (SD):

0009-0008-7877-5574

• Aurora Duarte-López (AD):

0009-0005-0386-1046

• Olga Zambrano (OZ):

0000-0003-4867-2351

• Jesús A. Luengo-Fereira (JL):

0000-0002-2780-5496

Authors’ contribution

SD: Treatment and clinical and radio-

graphic follow-up of the case. Conception,

design, analysis, and interpretation of data,

editing, review, and approval of the final

version of the manuscript to be published.

Funding support. AD: Analysis and interpre-

tation of data, editing, review, and approval

of the final version to be published. OZ: Con-

ception, design, analysis, and interpretation

of data, editing, critical review, and approv-

al of the final version to be published. JL:

Analysis and interpretation of data, critical

review, and approval of the final version to

be published.

386 Duarte-Inguanzo et al.

Investigación Clínica 65(3): 2024

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