Xu and Liu

Int Chin J Dent 2003; 3: 76-81.

Evaluation of maxillary protrusion malocclusion treatment effects withprosth-orthodontic method in old adults
Peicheng Xu, DDS, MSD,a and Honghu Liu, DDS, PhDbaShanghai Xuhui Dental Hospital and bHonghu Dental Clinic, Shanghai, P. R.
China
Purpose: To evaluate the treatment effects of maxillary protrusion malocclusion with prosth-orthodontic
method in old adults, which is a combined use of prosthodontics and orthodontics.
Materials and Methods: Totally 18 cases were treated by prosth-orthodontic method, including 16 females
and 2 males, average 45.6 years in age. Cephalometric analysis was applied to evaluate the treatment
effects. Angle and liner changes of pretreatment and post-treatment were determined and the results wereanalyzed by Student tests (p<0.05).
Results: Compared with pretreatment and post-treatment by prosth-orthodontic method, the angle changes
were significantly different in the measurement of U1-FH (p<0.05) and II (p<0.01), and the linear changes
were significantly different in the measurement of OB (p<0.05), OJ (p<0.01), Uls-AB (p<0.01), LLs-AB(p<0.05), Bs-AB (p<0.05), and C-St (p<0.05). After the prosth-orthodontic treatment, the angle of upperand lower incisors were changed to normal, the overbite and overjet were reduced to normal.
Conclusion: Prosth-orthodontics is an effective method for old adults. (Int Chin J Dent 2003; 3: 76-81.)
Clinical Significance: The results of the current study demonstrate that the prosth-orthodontics is aneffective method for old adults, especially for those who are not suitable for orthodontic treatment cases.
Key Words: cephalometric analysis, maxillary protrusion, orthodontics, prosthodontics, proth-orthodontics.

Introduction
Maxillary protrusion is a comparatively common kind of malocclusion in clinic.1,2 The marked labiallyproclination of upper incisors would cause gummy smile and disharmony of soft tissue profile in lips region,affecting the esthetics in facial side appearance and even bringing some psychological problems.3-5
However, the intraoral condition in middle age cases with maxillary protrusion malocclusion is completely
different from those in children and adolescence. Lack of dental health care, the intraoral condition inmiddle age cases is poor after many years of use, especially in dental malalignment cases. The concomitantsevere odontal diseases, periodontal diseases and dental misposition would bring a great many difficulties
to routine orthodontic treatment, some of which could not been orthodontically treated. In addition, manyof middle age cases would not accept the orthodontic treatment wearing fixed appliances for a 1-2 years ofperiod because of professional or social reasons. So in our clinic practice, the middle age cases with severe76

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Int Chin J Dent 2003; 3: 76-81.

anterior crowding were treated with porcelain prosthesis to re-align the anterior teeth, and the results weresatisfactory. The purpose of this study was to evaluate the efficacy of orthodontic prosthesis applied in 18
maxillary protrusion malocclusion cases in old adults.

Materials and Methods
Procedures of Prosth-orthodontics
Odontal diseases and periodontal diseases should be perfectly treated after routine dental examination(including panoramic films and cephalometric films). Two sets of models for each subject were used, one
for comparison before and after treatment as study model, the other one for tooth alignment experimenttransferred to dental articulator as work model in order to confirm the prosth-orthodontic design. Porcelain
prosthesis procedures were performed including root canal therapy, tooth preparation, getting work model
for porcelain prosthesis, temporary dummy making, dental color blending, finishing porcelain
prosth-orthodontic appliances and clinical insertion. Cephalometric films and study models were taken
after prosth-orthodontic treatment.
Measurements
Measurement Landmarks: There were 14 landmarks used in this study (Fig. 1), including Porion (P),
Orbitale (Or), Pogonion (Po), Menton (Me), Gonion (Go), Upper Incisor (UI), Lower Incisor (LI), Upper
Labrale (ULs), Lower Labrale (LLs), Subspinale (A), Supramental (B), Supramental of soft tissue (Bs),
Pogonion of soft tissue (Pos), Stomion (St).

Fig. 1. Measurement landmarks.

Fig. 2. Angle measurements.

Angular Measurements: There were 3 angular measurements (Fig. 2) analyzed, including angulation of
upper incisors (UI-FH) defined as inferioposterior angle formed by the intersection of upper incisor axis
and Frankfort horizontal plane, angulation of lower incisors (LI-MP) defined as superioposterior angle
formed by the intersection of lower incisor axis and mandibular plane, inter-incisal angle (II) defined as77

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Int Chin J Dent 2003; 3: 76-81.

posterior angle formed by intersection of upper and lower incisor axis.
Linear Measurements:

There were 8 linear measurements (Fig. 3) analyzed.

Horizontal distancemeasurements: ULs-AB, LLs-AB, Bs-AB, Pos-AB defined as lines separately drawn from points ULs, LLs,Bs, Pos perpendicular to the line connecting point A and point B. Vertical distance measurements: St-C
defined as the distance from the point C (the intersection point of UI-A and palatal plane) to thecorresponding point of St (the intersection point of a line drawn from St perpendicular to UI-A),
representing the length of upper lip. St-D defined as the distance from the point D (the intersection point ofLI-B and mandibular plane) to the corresponding point of St (the intersection point of a line drawn from St
perpendicular to LI-B), representing the length of lower lip. Overbite (OB): the vertical distance from UI
to LI. Overjet (OJ): the horizontal distance from UI to the labial surface of lower incisors.

Fig. 3. Linear measurements.

Fig. 4. Superimposition of pretreatment andpost-treatment cephalograms.

Data Collection and Statistical Analysis
After X-ray films tracing and measurements in a continuous period, Student test was applied to analyze
the data of pre- and post-treatment by using SAS statistical software in computer.

Results
Angular Changes before and after Treatment
They were shown in Table 1. There were statistically significant differences in the angulation of U1-FH
and II before and after treatment. No significant difference was found in the angulation of L1-MP.

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Int Chin J Dent 2003; 3: 76-81.

Table 1. Angle changes of pretreatment and post-treatment.
Measurement
U1-FH
L1-MPH1)

Pretreatment
112.5 ± 7.21
97.2 ± 6.47
102.8 ± 8.13

Post-treatment
94.8 ± 6.54 (1)97.2 ± 6.47
119.3 ± 8.97 (1)p<0.01

Linear Changes before and after Treatment
They were shown in Table 2. There were statistically significant differences in ULs-AB, OJ, LLs-AB,
OB and St-C. No significant difference was found in St-D.
Table 2. Liner changes of pretreatment and post-treatment.
Measurement
OBOJ
ULs-AB
LLs-AB
Bs-AB
Pos-AB
C-St
D-St
1)

p<0.01,(2)Pretreatment
5.01 ± 1.21
13.02 ± 2.35
27.61 ± 5.13
25.83 ± 4.82
18.40 ± 3.13
17.23 ± 3.12
33.50 ± 7.64
51.21 ± 9.71

Post-treatment
4.65 ± 1.34 (2)4.72 ± 2.17 (1)21.82 ± 4.98 (1)21.43 ± 3.97 (2)16.11 ± 2.79 (2)17.23 ± 3.12
31.30 ± 6.42 (2)52.41 ± 10.49

p<0.05

Superimposed Cephalometric Changes before and after Treatment
The superimposed cephalometric tracing before and after treatment (Fig. 4) showed clearly that, with themarked lingual replacement of upper incisors and length adjustment of the clinical crowns, the relationshipsof overbite and overjet in anterior region were significantly proved, also the soft tissue profile in lips region
was changed from notable protrusion before treatment to a more harmonious and esthetic appearance.
Tables 1 and 2 showed the decrease of UI-FH from 112.5 degrees before treatment to 94.8 degrees
indicating the significant lingual proclination of upper incisors, the decrease of anterior overjet by 9 mm
and the increase of II from 102.8 degrees before treatment to a more suitable 119.3 degrees resuming thenormal occlusal induction in anterior movement to some extent and its indirect protective effects on TMJ.

Discussion
Indications
With the raise of community total standard of living, the average life in Chinese population had been
obviously prolonged.

The more intensely pursuing health and esthetics, the more understanding theimportance of dental functions. Intraoral diseases in adults (including periodontal diseases, dental caries,
tooth missing and occlusal disturbance) become more severe in middle age period, so the demand forcomprehensive dental treatment including orthodontic treatment comes to grow up considering functions
and esthetics. However, the middle age patients we met in clinic have ignored the dental health care for along time, as a result, their crowding and protrusion malocclusion affecting the normal profiles often gowith the severe peridentitis (notable absorption in alveolar bone), wedge-shaped defect, severe odontal
diseases, attrition of tooth, root exposure due to gingival atrophy, dead tooth and defect of dentition. Such79

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Int Chin J Dent 2003; 3: 76-81.

intraoral condition would bring a great many difficulties to routine orthodontic treatment, some of which
could not been orthodontically treated. If this kind of middle age cases were orthodontically treated using
fixed appliances, their teeth would be loosened because of too quick movement and even the periodontal
tissue damaged more. In addition, many of middle age cases would not accept the orthodontic treatment
wearing fixed appliances for a 1-2 years of period because of the age, the professional or the other socialreasons. So the author treated this kind of patients by means of prosth-orthodontics to satisfy them, getting
marked improvement both in function and in esthetics finally within a short term (3-4 weeks) without
extraction, without wearing any appliances, and without affecting daily appearance.
Therefore, the indication of prosth-orthodontic treatment should be strictly and scientifically controlled.
The middle age patients with dental malalignment whose intraoral condition equal to orthodontic treatment
should be orthodontically treated firstly when they accepted the treatment planning. When some middle
age patients with dental malalignment could not be orthodontically treated due to poor intraoral condition,or they could not accept the long-term treatment wearing intraoral appliances, prosth-orthodontics
treatment would be another effective means considered of.
The Effects of Prosth-orthodontic Treatment on Hard Tissues and Soft Tissues in Maxillary
Protrusion Cases
The careful dental examination should be carried first before prosth-orthodotic treatment, including
analysis of dental and skeletal amount, analysis of arch length and width and cephalometric measurements.
On the basis of the design philosophy of prosth-orthodontics, working models transferred to a regulable
dental articulator were used to make sure the labiolingual inclination of upper and lower incisors, toconfirm the vertical height and to re-align the anterior teeth relieving crowding. Eventually the normal orapproximately normal relationships of overbite and overjet and the inducible occlusion during anterior
movement were achieved without abnormal occlusal interferences. So the dentist and the patient would all
agree with the treatment planning harmonizing the functions and esthetics.
A study by Yogosawa showed, the retrusive amount of the upper incisors had a correlation with that of
the upper lip significantly in the maxillary protrusion patients before and after treatment, and with that of
the lower lip to some extent. The results in our study also showed that, with the lingual replacement ofupper incisors, ULs-AB distance which indicating the degree of upper lip protrusion was decreased by 5.8mm, LLs-AB distance which indicating the degree of lower lip protrusion was decreased by 4.4 mm andBs-AB distance indicating the anteroposterior corresponding position of supramental in soft tissue wasdecreased by 2.3 mm. These results were consistent with those in Yogosawa’s study. In addition, St-C andSt-D indicating the length of upper and lower lip respectively were changed with the labiolingual
inclination and vertical position of anterior teeth, St-C decreasing by 2.2 mm and St-D increasing 1.2 mm.
Therefore, the replacement of anterior teeth led to some changes of soft tissue shape in lips region,
significantly improving the protrusive profile in esthetics and resuming the occlusal inducible function inanterior movement.
Clinical Key Points of Prosth-orthodontics

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Int Chin J Dent 2003; 3: 76-81.

Prosth-orthodontics was different from the routine orthodontics, with which we treated the patients inmiddle age who had odontal diseases or periodontal diseases demanding esthetical recovery urgently. Thus,in clinic, dentists should do a careful dental examination and a perfect treatment for the odontal disease orperiodontal disease before the prosthorthodontic treatment for malocclusion. In order to achieve the normalrelationships in anterior overbite and overjet and the harmonious profile, the dental re-alignment
experiment must be done in articulator before treatment and treatment planning set. The results of dental
re-alignment must be not only in accordance with dental physiology, but also reproducible exactly inpatients.
Based on the above principles of treatment, the malposed teeth should be crown-cut after perfect root
canal therapy. When the post was used for retention in a root canal filled teeth, the diameter of the post
should be designed considering the intensity of dentinum in order to enhancing the retention and stability,
avoiding dental crack. Usually the diameter of the post should be 1/3 of that of the root, and the post would
has the same length as the dental crown at least. The root canal preparing for the post should be operated as
carefully as possible without changing the inner anatomic structure. A metal ring could be manufactured
around the post on the occlusal surface of the root protecting the root from fracture. A shoulder prepared on
the occlusal surface of the root could decrease the wedge force effect leading to root crack when occlusal
force pressed. In addition, when crown cutting and root inner preparing, the relationship of the labiolingual
inclination of anterior teeth and the post design, as well as the accordance of prosthordontic appliances
intensity with the common path of insertion should be considered enough, avoiding the anterior occlusalinterference and establishing the normal occlusal inducible function in anterior movement.

References
1. Ueno T, Baba K, Fueki K, Ai M, Ohyama T. Influence of protrusive tooth contact on tapping point distribution. J Oral
Rehabil 2000; 27: 1004-11.
2. Capri D, Albehbehani Y, Smukler H. Augmentation of an anterior edentulous ridge for fixed prosthodontics withcombined use of orthodontics and surgery: A clinical report. J Prosthet Dent 2003; 90: 111-5.
3. Yeow VK, Chen YR, Su CP. Combining single- and double-tooth osteotomies with traditional orthognathic surgery. JCraniofac Surg 1999; 10: 447-53.
4. Yeow VK, Chen YR, Su CP. The role of multiple segment osteotomies in orthognathic surgery. Ann Acad MedSingapore 1999; 28: 660-4.
5. Chen YR, Yeow VK. Multiple-segment osteotomy in maxillofacial surgery. Plast Reconstr Surg 1999; 104: 381-8.

Reprint request to:
Dr. Peicheng Xu
Shanghai Xuhui Dental Hospital, Shanghai, P. R. China
FAX: +86-21-64226933 E-mail: dentistxu@citiz.net
Received on March 10, 2003. Revised on May 23, 2003. Accepted on July 29, 2003.
Copyright ©2003 by the Editorial Council of the International Chinese Journal of Dentistry.

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