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Fifty percent of the adult population suffers from periodontal disease. Patients with Stage IV periodontal disease have altered physiological dental relationships such as masticatory dysfunction, secondary occlusal trauma, increased tooth mobility, bite collapse, tooth migration and flaring. Occlusal forces can alter and adversely affect the outcome of periodontal therapy, thus orthodontic treatment can be considered to re-store occlusal harmony as well as improve smile aesthetics. The objectives of this article were 1) to underline the possible factors involved in the relationship between systemic conditions and periodontal disease during orthodontic treatment in patients with periodontal issues; 2) to propose an Orthodontic-Periodontal Risk Assessment model (OPRA) to account for risk factors associated with orthodontic treatment, estimating their impact on periodontal health in susceptible patients.
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G. Paolantoni
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Annali di stomatologia
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The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease
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Original Article
2022-08-08
2022-08-08
2020-12-01
2023-12-04
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Ann Stomatol (Roma)
G. Paolantoni
2020
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Private practice in Naples
1971-1441
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The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease
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                                                                                                      Original article


The Orthodontic-Periodontal Risk Assessment
(OPRA) in developing Periodontal Disease


Marino Musilli1                                               maintenance of the corrected periodontal condition [3].
Sherry Lee2                                                   Lang and Tonetti [4] described the Periodontal Risk As-
Mauro Farella3                                                sessment (PRA) through the use of a functional diagram,
Guerino Paolantoni4                                           evaluating factors which influence the risk of disease
                                                              progression at an individual level. It would be useful to
1
  Private practice in Salerno                                 have a similar diagram for an Orthodontic-Periodontal
2
  Dental House Surgeon of University of Otago, Dunedin        interdisciplinary approach for guidance in choosing the
3
  Department of Oral Sciences                                 appropriate orthodontic treatment plan to preserve the
4
  Private practice in Naples                                  periodontal health. As suggested and underlined by sev-
                                                              eral Authors[5-8-9-10-11], there is evidence indicating
Corresponding Author                                          that orthodontic appliances can alter this delicate bal-
Dr. Guerino Paolantoni                                        ance between defense and host.
Address: Via Francesco Giordani, 30, 80122 Napoli NA          However, we can only infer a negative influence of risk
Phone: +39 081 681418                                         factors related to the accuracy of the forces exerted on
Fax: +39 081 681418                                           the tissues by orthodontics appliances [12-15].
Email: paolantonicorsi@gmail.com                              In patients with high susceptibility to periodontal disease,
                                                              these orthodontics risk factors need to be considered
                                                              and managed appropriately or they have the potential
Abstract                                                      to cause an imbalance in the orthodontic-periodontal in-
                                                              terface [16].
Fifty percent of the adult population suffers from
periodontal disease. Patients with Stage IV peri-
odontal disease have altered physiological dental             Methods
relationships such as masticatory dysfunction, sec-           In order to explain the adverse effects occurring on
ondary occlusal trauma, increased tooth mobility,             patients susceptible to periodontitis during orthodontic
bite collapse, tooth migration and flaring. Occlusal          treatment, we hypothesized that some factors common
forces can alter and adversely affect the outcome             to periodontitis (device cleanability and periodontitis sus-
of periodontal therapy, thus orthodontic treatment            ceptibility) combined with those specific to orthodontics
can be considered to re-store occlusal harmony as             (treatment duration, device force system accuracy and
well as improve smile aesthetics. The objectives of           device extension and gingival phenotype) may influence
this article were 1) to underline the possible factors        periodontal health conditions in interdisciplinary ortho-
involved in the relationship between systemic con-            perio therapy:
ditions and periodontal disease during orthodontic
                                                              A.   Periodontal anchorage teeth preservation
treatment in patients with periodontal issues; 2) to
                                                              B.   Device cleansability
propose an Orthodontic-Periodontal Risk Assess-
                                                              C.   Treatment time
ment model (OPRA) to account for risk factors as-
                                                              D.   Force system accuracy
sociated with orthodontic treatment, estimating their
                                                              E.   Gingival Phenotype
impact on periodontal health in susceptible patients.
                                                              F.   Patient susceptibility to periodontitis
Keywords: Interdisciplinary therapy, risk assess-             The Alveolar Bone Housing [17] has not been directly in-
ment, Ortho-Perio strategies, periodontal diseases,           cluded amongst the previous factors for several reasons
orthodontics, orthodontic appliances, dental plaque,          later explained in the discussion, but is still indirectly
biofilms                                                      considered within the Gingival Phenotype.
                                                              For simplicity, these factors can be categorized into
                                                              three areas:
Introduction                                                  A) Device (related to the infectious stimulus group)
                                                              B) Load (related to the mechanical stimulus group)
As highlighted by the new periodontal classification,
                                                              C) Periodontal aspect (related to the involved periodon-
secondary occlusal trauma can negatively influence the
                                                                 tal teeth group)
course and expression of periodontal disease, attributing
to it a greater degree of complexity of treatment (Stage
IV Interdisciplinary approach) [1,2]. In an interdisciplin-   a. Periodontal anchorage teeth preservation
ary orthodontic-periodontal approach, treatment aims to       Orthodontic movement of teeth alters the homeostatic
rebalance occlusal function and facilitate the long-term      environment in both a healthy and reduced (healed)
Annali di Stomatologia 2020; XI (1-4): 16-27                                                                                 16
     The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease

     periodontium. During orthodontic treatment, it would be         on patients with an average age of fourteen years [8,29,
     desirable to move only the teeth that are planned to be         30], but we know that the peak in incidence of severe
     moved, and avoid placing additional stress on the other         chronic periodontitis is around 38-40 years of age [31].
     teeth, especially if there is already reduced periodontal       From a biological point of view, it is easier for the peri-
     support.                                                        odontium of younger patients to revert back to a healthy
     Orthodontic appliances commonly incorporate all teeth           condition after debonding.
     in both dental arches, as dental arches must be coordi-         Clear aligners and other types of minimally invasive ap-
     nated. As a result, position of all teeth changes in order      pliances have recently appeared in the orthodontic land-
     to facilitate this. The orthodontic management of seg-          scape. It has been shown that clear aligners simplify oral
     ments with reduced residual periodontium presents con-          hygiene measures for both the individual and profession-
     siderable difficulties with regards to the force intensity      al [32]. Minimally invasive orthodontics use wires with or
     and direction of movement. Errors are often made, cre-          without brackets bonded in a limited area within the den-
     ating periodontal disorder as seen in occlusal trauma.          tal arches by which precise forces through a statistically
     Careful planning and selection of teeth to be moved will        determined system can be applied [33, 34].
     help avoid unwanted and undesirable movement on the
     teeth we do not want to move or stress with high-risk           c. Treatment Time
     force systems. Despite decreasing the magnitude of
                                                                     It is best to minimize the duration of orthodontic treat-
     force application in teeth with reduced periodontal sup-
                                                                     ment in patients susceptible to periodontitis as orthodon-
     port, there will still be a vertical extrusive effect (due to
                                                                     tic treatment is considered a sterile inflammatory pro-
     the “cone effect”) [18] as well as unpredictable move-
                                                                     cess. Not only do orthodontic devices lead to a greater
     ments (due to the sudden change in position of the
                                                                     accumulation of biofilm, but they also result in a biofilm
     Center of Resistance). Physiologic bone resorption on
                                                                     composition change towards periodonto-pathogenic
     the already thin and fragile cortical bone in periodon-
                                                                     bacteria. Therefore, a prolonged period of orthodontic
     tally-compromised dentitions can occur in orthodontic
                                                                     therapy becomes a co-factor in the risk for periodontal
     tipping movements due to the concentration of tensile
                                                                     recurrence [35].
     and compressive stresses on the alveolar margins and
                                                                     The duration of orthodontic therapy also represents the
     root apex [19].
                                                                     period in which the periodontium of a patient susceptible
     With the introduction of mini-screws in orthodontics [20,
                                                                     to periodontal disease is exposed to mechanical stimuli
     21], undesirable forces and movement of anchor units
                                                                     – further activating the inflammatory mediators impli-
     have been reduced. Mini-screws, mini-plates or con-
                                                                     cated in orthodontic tooth movement. The duration of
     ventional implants are recommended for better control
                                                                     treatment is associated with the complexity of the initial
     of three-dimensional tooth movements [22]. Through
                                                                     malocclusion, the effectiveness of the orthodontic appli-
     time and development, the use of these anchoring de-
                                                                     ances chosen and the desired treatment outcomes.
     vices have become more specific, limiting the exten-
                                                                     In conventional orthodontic therapy, the goal is to obtain
     sion of orthodontic appliances as well as minimizing the
                                                                     an Angle Class I occlusion, in line with the Andrew’s Six
     duration of treatment. Thus with the use of TADs, it is
                                                                     Keys of Occlusion [36]. The achievement of this treat-
     now possible to avoid unnecessary biological stimuli
                                                                     ment outcome is one of the most used reference param-
     or round-tripping movements on compromised anchor
                                                                     eters by orthodontic institutions around the world where
     teeth without undermining efficacy on the reactive unit
                                                                     the ideal occlusion is perceived as the most aesthetic
     (teeth that need to be moved).
                                                                     and most stable. Meta-analysis has shown that the av-
                                                                     erage duration of orthodontic treatment is approximately
     b. Cleansability of Device                                      24.9 months [37] with no major differences between ado-
     This is based on the assumption that the increase in bac-       lescents and adults [38]. In the context of fixed devices,
     terial mass on tooth surfaces can easily lead to the wors-      treatment which include dental extractions are often of
     ening of periodontal health - gingivitis and recurrence of      longer duration than those without dental extractions [39].
     periodontitis [23, 24].                                         In reality, this concept is changing, as many studies
     The most widespread orthodontic device is the fixed             have shown that post-orthodontic stability is not guar-
     multi-bracket appliance. A single wire (with or without         anteed [40]. For this reason, orthodontic treatment out-
     loops) or several wires involving different sectors of the      comes involving a compromised occlusion may need to
     arch can be inserted into the brackets. Maintenance             be considered, as long as the occlusion is stable. In the
     of oral hygiene with fixed metal appliances is very dif-        orthodontic-periodontal interface, longer treatment dura-
     ficult and without proper hygiene, the increase in bacte-       tions are associated with greater periodontal stimulus
     rial load around the brackets leads to a higher gingival        from prolonged orthodontic forces and pro-inflammatory
     bleeding index [25-27]. Greater oral hygiene problems           factors within the periodontium.
     including plaque deposits were also found with the lin-
     gual bracket system [28].                                       d. Accuracy of Force Systems
     Previous reports show that clinical periodontal pa-
                                                                     Different orthodontic appliances create different force
     rameters partly normalized in three months following
                                                                     vectors on the periodontium [41]. Ideally, knowledge of
     the removal of fixed appliances [11]. However, it can
                                                                     the magnitude and direction of the force systems act-
     sometimes take between six months to two years post-
                                                                     ing on the teeth will lead to treatment with more pre-
     treatment for levels of supra- and subgingival Colony
                                                                     dictable outcomes [42, 43], however in reality, it is not
     Forming Units (CFU) to reach pre-treatment values. It
                                                                     possible to know or maintain the applied force vector for
     is worthwhile noting that these studies were conducted
                                                                     most orthodontic appliances between appointments. As

17                                                                                      Annali di Stomatologia 2020; XI (1-4): 16-27
M. Musilli et al.

a result, there is an automatic variability in orthodontic      phenotype when the necessary orthodontic tooth move-
force systems, capable of changing the direction of den-        ment will compromise the bony housing. Similarly, soft
tal movement (the phenomenon of “dental fluctuation”)           tissue PhMT may be needed to perform CAOT (Corticot-
[44], leading to treatment not completely identical to the      omy-assisted orthodontic therapy), or in conjunction with
programmed alignment (“indiscriminate alignment”) [44].         bone grafting. Thus, there are clinical situations in which
Among these variables, we can mention the anchorage             both bone and soft tissue augmentation are necessary
value deriving from the occlusion and the musculature of        [51]. A study also explored the labial gingival thickness
the patient, the soundness of the residual periodontium         using CBCT imaging and found a moderate association
and the occlusal sensitivity of the patient to the occlusal     with the underlying bone radiographically [53].
changes occurring during tooth movements. Swinging              It is important to clinically assess and record findings
movement of the teeth (jiggling) linked to the unpredict-       regarding the gingival phenotype prior to commencing
able creation of occlusal prematurities in patients with        orthodontic treatment as it is not only to reduce the risk
a reduced vertical pattern results in tooth mobility very       of gingival recession, but also to be aware of the alveolar
similar to those present in secondary occlusal trauma           bone housing and the boundaries of orthodontic tooth
[45]. This method of managing orthodontic movements             movement.
is the prerogative of a group of techniques that we could
classify as “continuous arch techniques”. The name is           f. Patient susceptibility to periodontitis
inspired by the fact that there is often only a single wire
                                                                Periodontitis is a complex, chronic inflammatory disease
engaging all the brackets of each arch. Clear aligners
                                                                as a result of an imbalance of the oral microbiota and
work with a similar force system treating entire dental
                                                                the host response leading to inflammation and destruc-
arches with a single device with the same characteristics
                                                                tion of the periodontium in susceptible individuals [54].
of elasticity.
                                                                Although bacterial presence is essential, there are also
An alternative to this approach is the “segmented arch
                                                                other contributing factors such as individual susceptibil-
technique” [46-48]. This is characterized by brackets
                                                                ity, certain systemic diseases (i.e. diabetes), smoking
on all teeth connected by different wire segments (also
                                                                and the presence of excessive occlusal stress. These
with different Load/Deflection characteristics). With a
                                                                can all act as co-factors for the disease onset and pro-
segmented arch approach, we tend to differentiate the
                                                                gression [55, 56]. In recent years, there has been greater
active units (teeth to be moved) from the reactive units
                                                                attention from the international scientific consensus on
(teeth that are stationary), using carefully applied forces
                                                                occlusal aspects and masticatory dysfunction, where
for more predictable movements.
                                                                these factors are now included and characterize the
A third method of working with more calculated, accurate
                                                                staging of the new periodontal classification [57]. In ad-
and longer-lasting force systems, allowing extremely
                                                                dition to periodontopathogenic bacterial elimination and
delicate movements is the Statically Determined System
                                                                lifestyle changes, therapeutic strategies must also focus
[49]. A statistically determined system implies “that the
                                                                on controlling malpositioning of the dental elements and
law of statics (equilibrium) is sufficient to solve” and they
                                                                abnormal occlusal forces. At each stage of inter-disci-
provide us with the most predictable knowledge of force
                                                                plinary treatment, the lack of control can affect treatment
systems [41, 44-49]. Therefore, this force system could
                                                                outcome [58].
be the most suitable for teeth or groups of teeth with very
                                                                In 2018 a new Classification scheme for periodontal and
small residual periodontium.
                                                                peri-implant diseases was proposed as part of the World
                                                                Workshop on Classification of Periodontology [1, 54],
e. Gingival Phenotype                                           establishing the stage, extension, complexity and sever-
Gingival phenotypes are distinguished into three cat-           ity of periodontitis through the attribution of the grade,
egories - thin, medium or thick but currently, a simple         risk of progression and susceptibility of the disease. This
method to identify gingival phenotype in patients does          new classification incorporates many factors that were
not exist. The available evidence indicates that subjects       previously evaluated in other procedures (Periodontal
with thin and narrow gingiva tend to have more gingi-           Risk Assessment) [56], designed to monitor and evalu-
val recession compared with those with thick and wide           ate health and/or disease characteristics of the patient.
gingiva. [50, 51]. This risk is increased with orthodontic      In order to reflect on the intrinsic periodontal characteris-
therapy and may be clinically apparent over time after          tics of the orthodontic patient, this periodontal parameter
orthodontic treatment [2]. To prevent gingival recession,       has also been included in the synoptic table. The work
many authors have suggested modifying the gingival              of Heitz-Mayfield et al 2020 [59] placed the least com-
phenotype prior to, or during orthodontic treatment.            promised values (with the least risk of progression [1A])​​
The benefits of phenotype modification therapy involving        towards the center of the polygon and those with greater
soft tissue augmentation (PhMT-s) during orthodontic            impairment of the periodontal status (with an increased
treatment remain undetermined due to the limited num-           risk of progression ([4C]) towards the external part. We
ber of studies available in the literature, however, PhMT       propose to quantify the six discussed variables to cre-
via corticotomy with particulate bone grafting (PhMT-b          ate a functional diagram which will help clinicians in their
along with corticotomy-assisted orthodontic therapy -           treatment with regards to the orthodontic-periodontal in-
CAOT) may provide clinical benefits. Augmenting peri-           terface (Figure 1).
odontal phenotypes expand the scope of incisor move-            Scores for the Orthodontic-Periodontal Risk Assessment
ment [52]. Furthermore, Kao et al. suggests that Bone           In order to make the following graph more availabe and
phenotype modification therapy (PhMT) should be pur-            easier to reproduce, a numerical scale from 1 to the 10
sued prior to orthodontic treatment in patients with thin       has been chosen, attributing the value 10 to a maximum

Annali di Stomatologia 2020; XI (1-4): 16-27                                                                                  18
     The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease




     Figure 1. Ortho-Perio Risk Assessment: I) TOP view. The chart is on a plane with macro areas: A) DEVICE (belonging to the
     infectious stimulus group), B) LOAD (belonging to the mechanical stimulus group, C) PERIODONTAL ASPECT (belonging to
     Involved periodontal teeth group). Inside there are five vectors that describe the risk factors associated with the orthodontic de-
     vice: a) Periodontal anchorage teeth preservation, b) Kind of Orthodontic Appliance (device cleanliness), c) Orthodontic Treat-
     ment Time, d) Force System Accuracy, e) Gingival Phenotype. The following PERSPECTIVE view (II, III, IV, V and VI) show the
     sixth vector and how it can increase the vertical dimension of the 3D chart: f) Periodontal Susceptibility.



     risk, the value 5 to an average risk and the value 1 to a            e) Gingival Phenotype
     minimum risk.                                                        10: Thin phenotype
                                                                          5: Medium phenotype
     a) Periodontal anchorage teeth preservation                          1: Thick phenotype
     10: all reactive forces are applied to teeth with reduced
     but healthy periodontium (no miniscrews are used)                    f) Patient’s susceptibility to periodontitis (Stage and
     5: the side effects on the anchorage teeth are limited               Grade)
     by the use of miniscrews (use of biomechanically ori-                4C: Up to Stage 4, Grade C
     ented skeletal anchorage) OR anchorage teeth are not                 3C/4: Up to Stage 3, Grade C
     involved with the orthodontic appliance OR if anchorage              3A/B: Up to Stage 3 Grade A/B
     teeth are involved, they have intact periodontium                    2A/B: Up to Stage 2 Grade A/B
     1: the teeth with healed but reduced residual periodon-              1A: Stage 1 Grade A
     tium that we do not want to move are not involved by the
     orthodontic device (Minimally invasive therapies with the            The assignment of values of the first five vectors of
     use of miniscrews)                                                   OPRA defines an area whose extension is directly pro-
                                                                          portional to the risk this device can induce a recurrence
     b) Cleansability of Device                                           of periodontal disease in periodontally susceptible pa-
     10: when the appliance is placed on the lingual side                 tients. It is important to note that the grading includes
     5: when the appliance is placed on the labial side (splints          patients with different periodontal susceptibility, as indi-
     on lingual side included)                                            cated in the new periodontal disease classification [1].
     1: when the appliance is a Clear Aligner or Minimally In-            Thus, it is empirical to pay attention to the first five OPRA
     vasive Orthodontics                                                  vectors (related to the appliance) in relationship with the
                                                                          sixth OPRA vector (related to the host susceptibility to
     c) Treatment time                                                    periodontal disease).
     10: for therapies with an expected duration beyond two
     years                                                                Calculating the patient’s orthodontic-periodontal risk as-
     5: for therapies with an expected duration greater than              sessment
     one year and less than two years                                     The OPRA is a three dimensional chart where the first
     1: for therapies with an expected duration of less than              five vectors lie on a flat polygon and the Periodontal
     a year                                                               Susceptibility (PS), the sixth vector lies in the centre.
                                                                          The first five vectors considered are exclusively related
     d) Accuracy of force systems                                         to the device and they potentially express nociceptive
     10: continuous archwire and aligners                                 stimuli capable of influencing the state of periodontal
     5: segmented archwire approaches                                     health.
     1: Minimally Invasive Orthodontics (statically determined            General results from the first five vectors (Fig 2):
     systems)                                                             - Low-risk: all parameters in the low-risk category (Fig
                                                                              2c)

19                                                                                            Annali di Stomatologia 2020; XI (1-4): 16-27
M. Musilli et al.

-    Moderate-risk: at least one parameter in the moder-          odontic appliance without fixed brackets with a statically
     ate-risk category (Fig 2b)                                   determined system with use of skeletal anchorage in a
­	   High-risk: at least one parameter in the high-risk cat-      patient with a Stage 4 grade C, presenting all vectors in
     egory (Fig 2a)                                               the low-risk category.
                                                                  In order to fully express its potential and simplify orth-
General considerations following integration of all six           odontic treatment decisions, the OPRA must address the
vectors:                                                          patient’s existing periodontal health status as well as the
When PS (the sixth vector) is 1A (Stage 1 grade A),               teeth undergoing orthodontic displacement.
all the other parameters are on the flat plane (Fig 2a),
meaning a high-risk orthodontic approach is possible
                                                                  Results
with low periodontal susceptibility. On the other hand,
when PS (the sixth vector) is 4C (Stage 4 grade C) the            Although this procedural algorithm (OPRA) is based
centre is raised (the PS vector) (Fig 2c); meaning that it        partly on scientific evidence and partly on the opinion of
is advisable to treatment plan using a low risk orthodon-         authoritative clinicians, it has allowed us, in the last few
tic approach due to the high periodontal susceptibility of        years of our clinical activity, to simplify the therapeutic
the patients in developing periodontal disease.                   choices in Orthodontic-Periodontal stage IV cases, mak-
                                                                  ing them more effective while reducing the risk of pro-
Figure 2 shows three types of OPRA related to three dif-          gression and recurrence of periodontal disease in this
ferent types of orthodontic devices and three different           particular type of patient.
type of periodontal susceptibility. In Figure 2a, a fixed         The three types of sample patients shown below have
vestibular orthodontic appliance on both arches accord-           the sole purpose of making the international scientific
ing to the continuous arch technique without the use of           consensus understand what options they can take in
skeletal anchorage, in a patient with a Stage 1 grade A.          carrying out these complex clinical cases.
It presents three of the five vectors (Periodontal anchor-        That is, the sample shows how the patient’s periodontal
age teeth preservation, Accuracy, Gingival phenotype)             characteristics at the systemic level, at the tooth level
in the high-risk category, one vector (Cleanliness) in            and at the site level have influenced orthodontic choices
the moderate-risk category and one vector (Treatment              in terms of choice of device, direction and duration of
time) in the low-risk category. Figure 2b shows a fixed           the forces.
orthodontic appliance on a single arch according to the
segmented technique with the use of skeletal anchor-
                                                                  Explanatory Clinical Case
age in a patient with a Stage 2 grade B. It presents four
of five vectors (Periodontal anchorage teeth preserva-            The three clinical cases presented in Figures 4, 5 and 6
tion, Cleanliness, Accuracy and Gingival phenotype) in            show the importance of selecting the appropriate orth-
the moderate-risk category and one vector (Treatment              odontic appliance with regards to the patient’s periodon-
Time) in the low-risk category. Figure 2c shows an orth-          tal status.




Figure 2. a) Fixed vestibular orthodontic appliance on both arches according to the continuous arch technique, without the use
of skeletal anchorage, in a patient with a Stage 1 grade A. b) Fixed orthodontic appliance on a single arch according to the
segmented technique, with the use of skeletal anchorage, in a patient with a Stage 2 grade B. Miniscrews help to reduce side
effects on anchorage teeth that have a reduced but healed periodontum c) Orthodontic appliance without brackets with a stati-
cally determined system with use of skeletal anchorage (Minimally Invasive Orthodontics), in a patient with a Stage 4 grade C.
Due to the use of miniscrews, no anchorage teeth with a reduced but healed periodontum are involved.

Annali di Stomatologia 2020; XI (1-4): 16-27                                                                                     20
     The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease




     Figure 3. Procedural flowchart summarizing all the diagnostic and therapeutic steps of the interdisciplinary approach in peri-
     odontal patients who must undergo orthodontic therapy. When and how to evaluate orthodontic therapy.



     OPRA gives us a tool to evaluate various orthodontic ap-          notype. The most recent orthodontic techniques have
     pliances and their effect on periodontal relapse. When            instead decreased dental extractions as a procedure for
     the patient has a Stage 1 Grade A periodontitis or a low          relieving crowding by expanding the dental arches both
     PRA, we can use any orthodontic device - high, medium             sagittally and transversely, in the hope of an expansive
     or low OPRA (Figure 2a). If the patient has a Stage 4             remodeling effect of the buccal alveolar bone. The con-
     Grade C periodontitis or a high PRA it is preferable to           cept is similar to that of the growth induced by functional
     use an orthodontic device with low OPRA (Figure 2c). It           appliances but with a lack of evidence in the literature
     would be better to choose an appropriate OPRA to peri-            [63, 64]. Subsequent studies by Melsen and Coll [65]
     odontitis Stage and Grade of the patients but in some             have verified with pre and post CBCT imaging that this
     cases this is not possible, especially when there are             effect cannot be guaranteed. As a result, it is increas-
     problems associated with the cleansability of the device          ingly believed that tooth movement in the labial direction
     or accuracy of the force system. In situations where it           must be contained within the thickness of the alveolar
     is not possible to avoid involving teeth with healthy but         bone, even if its pre-therapy evaluation cannot be rou-
     reduced periodontium, a solution could be to increase             tinely performed on all patients, for evident ethical rea-
     the frequency of professional oral hygiene, decreasing            sons related to excessive radiation exposure. Ultimately,
     the magnitude of delivered forces or more frequent orth-          it is once again the common sense of the orthodontist to
     odontic appointments. For example, Case 1 (Figure 4)              avoid excessive expansions, perhaps referring clinically
     and Case 2 (Figure 5) have the same periodontal stage             to the gingival phenotype [62 - 67].
     with a minor difference in Grade. The solution from the           Since Alveolar Bone Housing is not an easily parameter-
     OPRA point of view is to apply a medium risk appliance            izable factor, nor is it valuable for all patients (due to radi-
     as shown in Case 2 (Figure 5). When it is not possible            ation and ethical reasons) [68] as the regulation of dental
     to select the most appropriate appliance, it is recom-            movement within its scope is linked to the sensitivity and
     mended to increase the frequency of orthodontic ap-               prowess of the clinician, the authors have decided not
     pointments and professional hygiene visits.                       to include it amongst the elements of the OPRA chart,
                                                                       intending that tooth movement beyond the boundaries of
     Discussion                                                        the basal bone is limited as much as possible. Instead of
     The Alveolar Bone Housing is an important factor which            an Alveolar Bone Housing vector, we intended to use the
     warrants some discussion. This concept, previously sug-           Gingival phenotype as a vector as it is more frequently
     gested by Tweed, refers to the positioning of teeth above         related to the Alveolar Bone Thickness and is more eas-
     the basal bone [60, 61] and is quite well demonstrated            ily detectable by the clinicians [69].
     by Wennstrom’s primate studies [62]. It is understood             With the new Periodontal Diseases classification [1] we
     that moving the teeth beyond the thickness of the alveo-          can consider a number of parameters that will allow us
     lar bone is strongly correlated to the onset of gingival          to easily attribute the stage of impairment and the risk of
     recession, especially in conditions of thin gingival phe-         periodontitis progression.

21                                                                                         Annali di Stomatologia 2020; XI (1-4): 16-27
M. Musilli et al.




Figure 4. CASE 1: Periodontitis: STAGE III - GRADE B. Relationship of Class I on both sides. Need for interdisciplinary treat-
ment to correct the misalignment and extrusion of the 21 that caused functional disorders. The initial Scores (included Full
Mouth Plaque Score [FMPS] and Full Mouth Bleeding Score [FMBS]) are too high to proceed with an orthodontic therapy. At the
re-evaluation after 3 months from Step 1 and 2, we proceeded with regenerative surgery from 13 to 23 to correct the periodontal
defects. We waited about 1 year (until all periodontal scores indicate stable healthy conditions), and then orthodontic therapy
began using a Definitive Orthodontic treatment plan: Alignment on both arches and OVB correction. At the end of the move
which lasted about 12 months, the patient was given an increase in the volumes of the incisors, using a composite to improve
the aesthetics of the smile. OPRA scores: Periodontal anchorage teeth preservation = 10 (all teeth are involved including teeth
with reduced but healed peridontium, no miniscrews were used); Cleanliness = 5 (fixed appliances placed on labial surfaces
of the teeth on both arches); Treatment Time = 1 (expected duration of less than 1 year); Accuracy = 10 (continuous archwire
approach used through bracket free fixed appliance); Gingival phenotype = 5 (medium phenotype).




Given the complexity in the management of patients with           The most complex Orthodontic-Periodontal steps are
periodontal disease [22], it is essential to intervene with       characterized by:
an extremely cautious interdisciplinary approach using            1- Choosing the most appropriate orthodontic strategy.
a procedural algorithm such that all required multi-dis-          2- Timing of orthodontic tooth movements.
ciplinary treatment is performed with the correct timing.         3- Maintaining good periodontal control during orthodon-
Therefore, we consider it useful to implement the guide-          tic therapy.
lines of Stage I-II-III [70] with additional steps, presenting
these cases a degree of complexity of the major treat-            Choosing the appropriate orthodontic strategy
ment (Figure 3).                                                  To establish an individualized therapeutic plan, it is es-
It should be noted that in the PRELIMINARY Phase,                 sential to know the periodontal status of patients at the
any orthodontic and gnathological strategies are envis-           initial consultation appointment. From this information
aged in order to evaluate the ideal approach to control           we can develop a Preliminary Orthodontic Treatment
malocclusion, mobility and para-functions in periodontal          Plan (Figure 3), evaluating the occlusal relationships and
patients.                                                         identifying factors that may hinder the normal conduct of
It is only in the phase of the DEFINITIVE interdisciplin-         therapy. Examples include:
ary treatment plan following comparison of the patient’s          - the presence or absence of tooth mobility [71]
periodontal risk profile with characteristics of the ideal        - the presence or absence of parafunctions (wear fac-
orthodontic device and stabilisation of all inflammatory               ets or muscle pain)
parameters can the most appropriate orthodontic treat-            We should firstly state our “ideal orthodontic goal”. This
ment modality be ascertained.                                     will be dependent on the patient’s periodontal status. In
During active orthodontic therapy, important procedures           this phase, any necessary stabilization of hypermobile
are performed to control the inflammatory values of the           elements with the use of a splint, as well as occlusal ad-
periodontal patient undergoing orthodontic treatment.             justments in patients with increased tooth mobility [72]
Monthly reassessment of periodontal vestments, me-                is carried out. This may allow for any necessary non-
chanical control of risk factors (if necessary) and moti-         surgical periodontal therapy to be performed more easily
vational reinforcement to correct home plaque control.            and reduce the risk of worsening periodontal health [73].

Annali di Stomatologia 2020; XI (1-4): 16-27                                                                                      22
     The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease




     Figure 5. CASE 2. Periodontitis: STAGE IV - GRADE C. Class I Relationship on both sides, with increased OVB (due to lower
     frontal teeth extrusion), increased OVJ with flared upper frontal teeth on the left side and diastema between them. Over-erupted
     26 as a result of the missing 36. Need for interdisciplinary treatment to correct the misalignment of both the upper and lower
     arches. The initial Scores (including FMPS and FMBS) are too high to proceed with an orthodontic therapy. After Step 1 and
     2, the residual defects were corrected at Step 3 with regenerative surgery using amelogenins and synthetic biomaterial scaf-
     folds. We waited only one month (until all periodontal scores indicated stable healthy conditions) to proceed from the surgery
     as movements began in the lower arch, without initially involving the upper arch affected by the surgery. Only after one year
     did we proceed with the move to the upper arch (mature healing achieved after surgery). The case finished with an additive
     ameloplasty in composite to reduce the imperfection of the lack of papilla between the 21 and 22. . OPRA scores: Periodontal
     anchorage teeth preservation = 5 (use of skeletal anchorage bio-mechanically oriented); Cleanliness = 5 (placement of fixed
     splints on lingual surfaces of the teeth); Treatment Time = 5 (expected duration greater than one year and less than two years);
     Accuracy = 5 (segmented arch wire approach); Gingival phenotype = 1 (thick phenotype)




     Orthodontic treatment should only commence following               It is also important to note that there are variations in the
     the active phase of periodontal therapy and then deter-            maturation and healing following different periodontal
     mining the most appropriate orthodontic strategy using             procedures. These range from a few days for Resective
     the value of the OPRA (Figure 3).                                  Surgery (ORS), to six months for Scaling, Root Planing
     Example: when a patient needs correction of the ante-              and Access Flap (AF), and up to one year for Regenera-
     rior deepbite, if posterior anchorage will compromise              tive Surgery (GTR and EMD) [71, 77-79].
     the posterior dentition (due to teeth with poor residual
     periodontal support), clinicians can opt for the exclusion         Maintaining good periodontal control during orthodontic
     of these sectors by using skeletal anchorage (temporary            therapy
     anchorage devices).                                                The presence of orthodontic appliances induces a
     If more than one treatment method is available to treat a          change in the normal saprophytic bacterial flora towards
                                                                        more pathogenic species [80] and increases the difficulty
     malocclusion, clinicians should choose the shorter treat-
                                                                        for patients to maintain good oral hygiene [81]. During
     ment option as well as one that facilitates easier oral
                                                                        orthodontic treatment, there are simultaneously areas
     hygiene.
                                                                        of bone neo-apposition and bone resorption in the peri-
                                                                        odontium around teeth that are being moved. In the ab-
     Timing of orthodontic tooth movements
                                                                        sence of plaque and inflammation, bony apposition and
     The literature remains unclear and somewhat contro-                resorption is defined as a sterile pseudo-inflammatory
     versial on the exact timing to start tooth movement after          process. The mediators RANK, RANKL, OPG, IL-1 / IL-
     periodontal therapy [74]. However, there is clear clinical         6, MMPs that regulate these movements also intervene
     evidence showing tooth movement enhancing the rate                 during the inflammatory processes of bone lysis as a re-
     of inflamed connective tissue attachment destruction for           sult of the inflammatory response [35].
     teeth with infra bony pockets [75, 76] and thus orthodon-          There is a need to formulate an individualized profes-
     tic treatment should only be performed on periodontally-           sional plaque control program for patients undergoing
     stable patients.                                                   orthodontic treatment to avoid the recurrence of peri-

23                                                                                          Annali di Stomatologia 2020; XI (1-4): 16-27
M. Musilli et al.




Figure 6. CASE 3. Periodontitis: STAGE IV - GRADE C. Class I relationship on both sides misaligned upper frontal teeth, 11
over-erupted. Need for interdisciplinary treatment to correct the extrusion of 11 that caused functional disorders. The initial
Scores (included FMPS and FMBS) are too high to proceed with an orthodontic therapy. The 11 was necrotic with considerable
mobility. We proceeded initially with splinting of the frontal group at the same time as the endodontic treatment of the 11. In
this case, steps 1 and 2 were sufficient to eliminate periodontal defects. Therefore, only 4 months after the start of therapy (all
periodontal scores indicated stable healthy conditions), the orthodontic shift was carried out using a bracket free segmented
approach with a Minimally Invasive Orthodontic appliance. A cantilever (statically determined system) on implant as anchorage
on the upper right side and a 10 gram single force on tooth 11 with a stainless steel rigid splint on the labial surface of the front
teeth, preventing proclination on 11 during the intrusive movement. OPRA scores: Periodontal anchorage teeth preservation = 1
(orthodontic anchorage on implant); Cleanliness = 1 (Minimally Invasive Orthodontics); Treatment Time = 1 (expected duration
of less than a year); Accuracy = 1 (statically determined system); Gingival phenotype = 1 (thick phenotype).




odontal disease (Figure 3). Our experience leads us to                Conclusions
suggest regular 30-minute hygiene appointments once
a month, especially for patients with Grade B and C                   Periodontal procedures are based on robust scientific
periodontitis. The following procedures should be car-                evidence whereas expert opinions are often relied on
ried out:                                                             in the orthodontic field. The intrinsic limits of the OPRA
- Periodontal re-examination                                          are currently linked to the arbitrariness of the selected
- Supra and subgingival instrumentation                               factors as they are based only on years of clinical expe-
- Reinforcement of oral hygiene motivation                            rience. We hope to be able to share its long-term effec-
During these monthly evaluations, if periodontal param-               tiveness in the future.
eters such as Full Mouth Bleeding Score (FMBS) are                    Author Contributions: Conceptualization, methodology,
greater than ten percent and probing depths of orthodon-              M.M and G.P..; validation, data curation, G.P., M.M.;
tically-involved teeth show increased values, there is a              writing—original draft preparation, M.M. G. P.; writing—
risk of periodontitis progression [82]. We will implement a           review and editing, M.M, G.P., G.S., S.L.; supervision,
procedure defined by us as “STOP and GO” whereby the                  G.S., M.M, G.P. All authors have read and agreed to the
orthodontic treatment is stopped, motivational oral hy-               published version of the manuscript.
giene is reinforced, and professional re-instrumentation is           Funding: This research received no external funding.
performed by the dental hygienist. Orthodontic treatment
only restarts when the periodontal parameters return to               Institutional Review Board Statement: Not applicable.
ideal conditions. This will make it possible to establish             Informed Consent Statement: Not Applicable
an individualized interdisciplinary procedure with extreme            Data Availability Statement: The data sets used and/or
precision, reducing the risk of recurrence or unexpected              analyzed during the current study available from the cor-
clinical events. Following treatment, patients should be              responding author on reasonable request.
placed on individualized maintenance programmes that
include three month recalls in patients with high PRA and             Conflicts of Interest: The authors declare no conflict of
six month recalls in patients with low PRA [83].                      interest.
Annali di Stomatologia 2020; XI (1-4): 16-27                                                                                            24
     The Orthodontic-Periodontal Risk Assessment (OPRA) in developing Periodontal Disease

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