Journal Club : Comparison of surgical and fixed functional treatment results in identical twins

Long-term surgical versus functional Class II correction:
A comparison of identical twins
Aditya Chhibbera; Madhur Upadhyayb; Flavio Uribec; Ravindra Nandad 

Angle Orthod. 2015;85:142–156.

This case report interested me because I have personally had a tough time using functional appliances and achieving long term stability of the Class II correction (molar relation and overjet) CONSISTENTLY.



Though relapse of Class II isn't always complete, yet cases that I have treated surgically have stood the test of time compared to Class II correction by other means such as Class II elastics, twin blocks.

Two identical female (age 13 years 3 months) were treated for Class II correction where one patient was treated nonsurgically using a fixed functional appliance, while the other was treated using orthognathic mandibular advancement surgery. The patients were recalled and evaluated 5 years in retention. 
The advantage of using twins for such comparisons is that the difference in outcome can be assumed to be epigenetic and thus directly the result of the intervention provided, i.e, surgery or Fixed Functional Appliance

The key question was ‘‘Are there esthetic differences when Class II correction is achieved with surgical intervention in comparison to camouflage using a fixed functional appliance, both in the short and long term?’’ This twin case report helps to elucidate some answers. 

Both the girls had similar growth status, near similar skeletal patterns and slightly different dental patterns. However one girl agreed to surgery and the other didn't

Patient 1 was thus treated nonsurgically with a Fixed Functional Appliance, twin force bite corrector for 10 months. The treatment objectives for patient 1 were: attempt to maximize the differential jaw growth by nonsurgical correction of the malocclusion, control the vertical dimension and space maintenance for the missing mandibular premolar for subsequent implant replacement, retention, and follow up.

The active treatment duration was 30 months at 16 yrs of age

 Patient 2 was treated with orthognathic surgery for Class II correction. For patient 2, the treatment objectives were: to surgically correct the underlying skeletal discrepancy, correct the vertical dimension by surgically impacting the maxilla, space maintenance for the missing mandibular second premolars and subsequent implant placement, retention, and follow up.

Surgery was planned when the patient was age 18 years and 2 months
The patient was subsequently debonded at the age of 18 years and 8 months after an active treatment time of 62 months

Comparison of Treatment Progress, Results, and Long-term Retention 

The cephalometric and clinical comparison of the twin sisters took place at three time points: pretreatment, posttreatment, and long-term retention

1. At the initial examination (13 years 3 months). Even though the skeletal A and B points were slightly backwardly positioned in patient 2 compared to patient 1, the underlying skeletal discrepancy associated with mandibular retrognathia and vertically maxillary excess was similar in both. The overjet was slightly more pronounced in patient 2 due to proclined maxillary incisors.

2. At the posttreatment level (age 16 years, 5 months for patient 1 and 18 years, 8 months for patient 2). The overall skeletal outcome was superior for patient 2. She showed greater skeletal Class II correction with good vertical control, while her twin had dental compensations. However, the esthetic outcome was similar in both patients.

 3. At the retention level (22 years and 9 months). Interestingly, even though the skeletal outcome of patient 2 remained superior, the soft tissue profile was still remarkably similar even though they underwent different procedures for Class II correction

PG - Useful information about TMD and Sleep quality correlation for your patients!

From a journal review by Vince Kokich in AO 2003, found this interesting bit about Sleep Quality and TMD. Something which you can confidently inform your patients about!

Sleep quality is a cofactor in temporomandibular disorders. TMD affects a portion of the patients treated by orthodontists. Although orthodontic therapy will not predictably ameliorate temporomandibular disorders, it is important to understand the pathology of TMD, and how it could affect or be affected by tooth movement. A recent study published in the Journal of Orofacial Pain (2002;16: 221–228), evaluated the quality of sleep as a participating factor in TMD. The sample for this study consisted of 137 consecutive subjects who had presented for evaluation at a university-based temporomandibular clinic. These individuals had a variety of problems, but all had varying degrees of craniomandibular pain and dysfunction. Before rendering any treatment, each subject was asked to complete three questionnaires. The first evaluated their quality of sleep, the second determined the subject’s level of psychological stress, and the third evaluated the degree of craniomandibular pain. From this data, the subjects were divided into two groups—good sleepers and poor sleepers. Then, the level of psychological stress and the degree of pain were compared between the two groups. The authors found that poor sleepers typically had higher psychological stress, higher pain, and less perceived life control. Furthermore, the authors determined that the quality of sleep could be predicted by the intensity of pain and the degree of psychological stress in patients with TMD. As a result, the authors concluded that sleep quality is a cofactor in many subjects with temporomandibular disorders.

Personally I have had good experiences where posterior crossbites, especially second molar complete buccal crossbites, when treated successfully eliminated pretreatment TMJ pain. However, the above article is worth keeping in mind when TMD doesnt seem to respond to therapy.

Whether a vice-versa situation i.e. whether TMD is the cause of poor sleep quality is worth another investigation!

PG A brilliant article on Accelerated tooth movement

LONG, PYAKUREL, WANG, LIAO, ZHOU, LAI 
Interventions for accelerating orthodontic tooth movement. A systematic review
Angle Orthodontist, Angle Orthod. 2013;83:164–171

In this systematic review, the authors have analyzed nine eligible studies of five types of interventions, within which six outcomes were evaluated. Among the nine included studies, 2 used mini- screws as anchorage to retract canines, while the remaining seven studies used first molars. For the seven studies, measurements of the moved distances of canines may be influenced by mesial movements of the first molars. However, in consideration of the methods for the measurements, the authors suggest that 4 studies  employed reliable methods and were not influenced by the mesial movement of first molars.

Low-Level Laser Therapy
For this intervention, accumulative moved distance, periodontal health, and root resorption were evaluated, but a meta-analysis was conducted only for accumulative moved distance. The pooled mean differences between the two groups regarding accumulative moved distance evaluated over 1,2 and 3 months intervals indicated that low-level laser therapy was unable to accelerate orthodontic tooth movement. However, two studies showed consistent results that laser therapy was safe in terms of periodontal and root health.
Therefore, the authors suggest that low-level laser therapy is safe regarding periodontal and root health and that it is unable to accelerate orthodontic tooth movement.

Corticotomy
The results from two included studies showed consistent results that corticotomy can accelerate orthodontic tooth movement. Moreover, both employed reliable methods to measure tooth movement and specified and used a similar start time of force applications between two groups, which would lend more credence to their results since the rates of tooth movement into healed and recent extraction sites are significantly different.  Moreover, the results showed that corticotomy in conjunction with mini-screws can dramatically augment posterior anchorage, which is of prime importance since effective anchorage would greatly improve orthodontic treatment results.

Since corticotomy is per se a surgical intervention on alveolar bones, it may have adverse effects on periodontal tissues. However, in this systematic review, neither study indicated that corticotomy would damage periodontal health, except that gingival index scores increased in the experimental group 1 study. The authors however suggest this may be simply a response of gingiva to alveolar healing, since alveolar healing following surgery takes at least 4 months. Thus, dental hygiene should be paid special attention during the healing stage after corticotomy.
Therefore, the authors suggest that corticotomy is relatively safe and is an effective intervention to accelerate orthodontic tooth movement.

Electrical Current
In this systematic review, only accumulative moved distance was evaluated. Kim et al revealed that electrical current was capable of accelerating orthodontic tooth movement. This study employed a reliable method to measure tooth movement. However, it did not specify the start time of canine retraction after first premolar extraction, which decreases the reliability of the results since canine retraction speed into healed and recent extraction sites differ.  Moreover, since only females were included in this study,the authors do not know the intervention effects in males.
Therefore, regarding unreliable methodology and results, we cannot determine whether electrical current would accelerate orthodontic tooth movement.

Pulsed Electromagnetic Fields
In this systematic review, only accumulative moved distance was assessed. Showkatbakhsh et al showed that a pulsed electromagnetic field was capable of accelerating orthodontic tooth movement. However, this study suffered from several drawbacks.
First, the study measured moved distance using an unreliable method. Second, this study did not specify the start time of canine retractions after extractions of the first premolars. Furthermore, the quality assessment indicates that this study is of low quality, which further limits the reliability of this study.
Therefore, with regard to unreliable methodology and results, the authors cannot determine the effectiveness of pulsed electromagnetic fields on accelerating orthodontic tooth movement.

Dentoalveolar Distraction vs Periodontal Distraction

Kharkar et al  showed that dentoalveolar distraction can accelerate orthodontic tooth movement compared with periodontal distraction. However, this study suffered from a significant drawback: the distractors were activated 2 days after first premolar extractions for dentoalveolar distraction, while they were activated immediately after first premolar extractions for periodontal distraction, rendering the two modalities incomparable. In addition, this study was of low quality. Thus, the authors cannot determine which modality would be more effective in accelerating orthodontic tooth movement. But with regard to the great differences in treatment duration between dentoalveolar or periodontal distraction and conventional treatment (10–20 days vs 6–9 months), the authors suggest that dentoalveolar or periodontal distraction is promising in clinical practice.
Moreover, both techniques cause negligible anchorage loss, and all the moved teeth were vital after 1 year for both techniques. Dentoalveolar distraction did not cause root resorption, while periodontal distraction did which may be attributed to extended duration of applied force required for periodontal distraction.
Thus, the authors suggest that dentoalveolar or periodontal distraction is safe and that the unreliable methodology and results limited the interpretation that these techniques are effective in accelerating orthodontic tooth movement.

The results of this systematic review must be interpreted with caution because of several limitations, including the small number of high-quality studies and limitation of statistical pooling due to clinical or methodological heterogeneity and noncomparability of outcome data.

CONCLUSIONS
1. Low-level laser therapy is safe but unable to accelerate orthodontic tooth movement; corticotomy is safe and able to accelerate orthodontic tooth movement.
2. Current evidence does not reveal whether electrical current and pulsed electromagnetic fields are effective in accelerating orthodontic tooth movement; dentoalveolar or periodontal distraction is promising in accelerating orthodontic tooth movement but lacks convincing evidence.

Journal Club : Is Microimplant stability dependent on the length of microimplant??

Effect of the length of orthodontic mini-screw implants on their long-term stability: A prospective study Michał Sarula ; Liwia Mincha ; Hyo-Sang Parkb ; Joanna Antoszewska-Smith. Angle Orthodontist, Vol 85, No 1, 2015

Though the conclusion of the study is very logical and obvious, what is important here is the way the study has been designed to isolate the variable to be tested (length of microimplant).

Being a prospective study in design, the authors have devised a well though of study to try and isolate "length of microimplant' as a variable to be tested.

LEARNING POINT
What is interesting here is that despite various factors that may affect Microimplant stability viz patient related (systemic diseases, smoking, habits, hygiene, the level of immunity, etc), orthodontist related (treatment methodology, experience), and TISAD/TAD related (size, surface coating, and shape), The authors have tried to standardize these complex variables so that the study becomes homogeneous and the only variable that remains is the length of implant (6 mm and 8 mm)

METHODS BY WHICH STANDARDIZATION WAS DONE
1. The study included a group of generally healthy patients of the same gender (female) and age (20– 29 years), who reported toothbrushing three times per day (after each meal) and no symptoms of any oral disease. Since it is known that a patient’s right- or lefthandedness may affect the long-term result,14 this aspect was also taken into account. All of the lefthanded patients were rejected from the study group.
2. All patients presented a Class I skeletal pattern with the hyperdivergent (in the range of 1 standard deviation) angle between the maxillary and mandibular planes. Only patients with planned extraction of the lower first or second premolar were included in the study group
3. Morphology of the oral mucosa (ie, frenula) in the area of implantation was also considered: only patients without frenula potentially loading the TISAD/ TAD head while chewing or facial movement were considered
4. To provide the highest homogeneity of the study material, the optical bone density (OPD) was evaluated in each individual, applying Østravik’s protocol (Useful method of standardization)
5. To obtain the same force characteristics, the maximum anchorage was introduced only in extraction cases (first or second premolar), for the purpose of the group retraction of the lower incisors and canines
6. All mini-screw implants were screwed by the same orthodontist and always according to the same Wroclaw protocol: N Working on both sides of a dental unit N Mandatory stab incision and predrilling mode N Placing the TISAD/TAD perpendicularly to the alveolar bone, which was allowed since the TISAD/ TAD were located 3 mm beneath the mucogingival junction, and therefore the roots were not jeopardized N Placing the TISAD/TAD between the first and second molars N Loading mini-screw implants after 2 weeks with a 13-mm NiTi spring (Dentos, Daegu, South Korea) with 100–150 g of force
8.All TISAD/TAD were evaluated considering the root proximity by taking periapical radiograms. If there was no contact or overlapping of the roots adjacent to TISAD/TAD, the case was included in the study. Only TISAD/TAD with no initial mobility or perfect initial stability were included. All patients were instructed to maintain a perfect oral hygiene regimen and to use gel with chlorhexidine
8. All individuals were asked to avoid any recurrent hit against TISAD/TAD and any hard contact with the toothbrush body.

THE DISCUSSION FURTHER ANALYZES THE STUDY DESIGN
1. One method of study design might be to establish a group with a large sample size that provides many different variables and to further analyze the impact of the variables on TISAD/TAD stability.Another approach is to analyze only one variable, on the assumption that the influence of other factors on the results is eliminated to the maximum(which was attempted in this study)
2. The strategy of analyzing only one variable also has a weak point: selection of a study group of patients, in whom the effects of all known factors are eliminated—except for the effect undergoing planned analysis—is technically very difficult. However, this difficulty may be overcome if a certain degree of homogeneity (deciding on the significance results) is strictly obeyed.(this was attempted by the methods mentioned above)
3.  On the other hand, high homogeneity has a kind of quid pro quo (something that comes along) limitation: it reduces the external validity of the obtained results, making them likely to match only the individuals strictly corresponding to the characteristics of the study group. Nonetheless, high homogeneity allows control of variables and facilitates the determination of the objective of further research. Therefore, it seems to be a good option for the purpose of clinical trial

STUDY DURATION - 9-12 months

Interesting studies mentioned in the article
1. META ANALYSIS  Papageorgiou SN, Zogakis IP, Papadopoulos MA. Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis. Am J Orthod Dentofacial Orthop. 2012;142:577–595 revealed that the length of the mini-screw implant was unimportant. However, according to these authors, both the close proximity to the root and too high torque during the TISAD/TAD insertion may increase the risk of their loss.


QUESTIONS THAT ARISE
1. Is 100-150 gms per side good enough for enmasse retraction?
2. Implants were loaded 2 weeks after placement. Why? Was it to improve the initial stability of the microimplant?

PG reading list

With so many textbooks and a whole lot of journals, it becomes increasingly difficult for PG students to skim through them and come up with something that pleases the teachers.
As a thumb rule, NOTHING will please your teachers. BUT, a sincere effort surely will!

This list will keep changing and expanding as more and more topics/trends/techniques come to the fore.

Essential textbooks for reading (what will build for you a strong foundation for your orthodontic career)

PROFFIT - A textbook that will be read by you lifelong and each time that you read even as a practitioner you'll relearn something. Especially the sections on Orthodontic diagnosis and treatment planning

CLARK's - for twin block, one of the most versatile myofunctional appliances

GRABER RAKOSI PETROVIC - for principles of myofunctional appliances, cephalometrics for functional appliances, diagnosis and treatment planning for functional appliances. Extremely important from Exam point of view.

MBT -  For principles of the MBT philosophy of treatment. Look meditatively at the finished results in this book and try to instill a sense of WHAT REALLY IS a finished case.

ALEXANDER DISCIPLINE - Though a couple of principles from the 20 that Wick has given to the world of Orthodontics may be redundant (e.g. the use of Headgears), this book should be read for instilling the concept of Discipline into your PG tenure. Discipline related to anything in Orthodontics will be the backbone of what you eventually make of yourself as an Orthodontist.
Truly E=R, go figure!

NANDA - Biomechanic and Esthetic strategies for Class II management
Since Class II constitutes one of the challenging cases and routine cases that we see in our population seeking treatment, read this book well for a beautiful clinical insight into its management.

BRANTLEY - Orthodontic materials
The last word on materials that comprise clinical orthodontics. Absolutely a must read

RECOMMENDED READING

FLETCHER - For the Begg technique
JAYADE - For refined Begg technique

OP KHARBANDA - For a great academic perspective of Indian clinical Orthodontics

PROFFIT WHITE -  For surgical orthodontic treatment planning and orthognathic surgery

SUNG KYUNG BAE PARK- Microimplants in Orthodontics which sooner or later will be a mainstay of your practice

UG Model analysis Ashley Howe's index

ASHLEY  HOWE’S  ANALYSIS

Parameters

·      TTM - Refers to sum of the mesiodistal width of the teeth from first molar to first molar

·      Premolar width (PMD) - Arch width is measured from the buccal cusp tips of the first premolar on one side to the buccal cusp tip on other side

·      PMBAW (premolar basal arch width) -  measured from the root apices of the first premolar on one side to the first premolar on other side

FIG 20  : Placement of dividers distal to the canine eminence to measure PMBAW

·      

Canine Fossa width - Measurement of width from canine fossa (immediate distal to canine root eminence) of one side to the other (Fig 20) gives us the width of the dental arch at the apical base or the junction between the basal bone & alveolar process

•       If canine fossa is not clear,  measurement is made from a point that is 8 mm below the crest of interdental papilla distal to canine

Following measurements have to be obtained

1.    Percentage of PMD to TTM

                  PMD X 100

                      TTM

2.    Percentage of PMBAW to TTM

                 PMBAW X 100

                         TTM

       

       Inference           

  If PMBAW > PMD :-

   it is an indication that basal arch is sufficient to allow expansion

  If PMD > PMBAW :-

    Can be three possibilities

   1) Contraindicated for expansion

   2) Move teeth distally

   3) Extract some teeth

•       According to Ashley Howe, to achieve normal occlusion with a full complement of teeth PMBAW should be 44% of TTM

•       Therefore if PMBAW X 100/TTM is:

   a) if 37% or less             case requires extraction   

   b) if 44% or more             treatment by non-extraction

   c) if between 37-44%             (border line case) may/may not require extraction                 

UG Model Analysis Pont's and Linder Harth index

Pont’s Index

Pont’s index helps in:

1.    Determining whether the dental arch is narrow or normal

3.    Determining how much expansion is possible at premolar and molar regions

The greatest width of incisors is measured with calipers recorded on a line, & their sum is recorded in millimeters

              This is termed as “sum of incisors” (SI)

Calculated premolar value (CPV)

The required arch width in the premolar region is calculated by formula:-

                 SI X 100

                     80

Calculated molar value (CMV)

The required arch width in the molar region is calculated by formula:-

                 SI X 100

                     64

Measured premolar value (MPV)

The distance between the upper right first premolar & upper left first premolar (that is the distal end of the occlusal grove) is recorded (Fig 17) & called as “measured premolar value” (MPV)

FIG 17 : Measurement of premolar width (MPV)

Measured Molar value (MMV)

The distance between the upper right first molar & upper left first molar (that is the mesial pit on the occlusal surface in maxillary arch ) is recorded (Fig 18) & is termed as “measured molar value” (MMV)

FIG 18 : Measurement of molar width (MMV)

Inference                    

Difference between the measured & calculated values indicate expansion or contraction of arches. The amount of contraction determines the needs for expansion

  1) If measured value is less, expansion is required

  2) If measured value is more, inference of expanded arch is drown and further expansion cannot be done.

Linder Harth Index

It is very similar to Pont’s analysis however he made a variation in the formula to determine the calculated premolar value as per the population sample.

·      Calculated premolar value:-

                    SI X 100

        85                      

·      Calculated molar value:-

        SI X 100

             65