Biomechanics of Space Closure (Group B Anchorage)

Types of Anchorage Based on Maximum Anchorage Demand

Anchorage is classified into three types based on the maximum anchorage required:

Type A: Maximum Anchorage

  • Definition: Anchorage demand is very high.
  • Space Utilization: Not more than 1/4th of the extraction space should be closed by forward movement of anchor teeth.
  • Mechanism: The extraction space is primarily closed by maximum incisor retraction.

Type B: Moderate Anchorage

  • Definition: Anchorage demand is moderate.
  • Space Utilization: Anchor teeth are allowed to move forward by up to half the extraction space.
  • Mechanism: The extraction space is closed by a combination of incisor retraction and posterior tooth protraction.

Type C: Minimum Anchorage

  • Definition: Anchorage demand is very low.
  • Space Utilization: More than half of the extraction space is closed by mesial movement of the anchor teeth.
  • Mechanism: The extraction space is primarily closed by protraction of posterior teeth with minimal incisor retraction.

Group B Anchorage: Biomechanics of Space Closure

Key Features

  • Archwire: A working archwire with a minimal curve of Spee (e.g., 0.019 × 0.025-inch SS wire) is engaged into the bracket slots and molar tubes.
  • Couples and Forces:
    • The wire generates a couple at the level of the bracket/molar tube at both ends, leading to the generation of a moment of couple (M_c).
    • Tiebacks create a force for space closure (F), generating a moment of force (M_F).
  • Force and Moment Interaction:
    • At either end of the system, the moments of couple and force are created in opposite directions, canceling each other.
    • This leaves only the translatory force (F) to exist, enabling space closure.

Translational Movement

  • When moments are balanced correctly:
  • No vertical component of force is produced.
  • No rotational tendency occurs in the system.
  • Occlusal plane and overbite remain unchanged.

  • Diagram: Depicts the working archwire (faded blue line) and the resulting forces and moments.
  • Outcome: Translation of anterior and posterior segments without altering the occlusal plane or overbite.

Planned Imbalance of Moments

  • In some scenarios, moments are deliberately imbalanced to achieve specific vertical movements:
  • Posterior Teeth: Extrusion (yellow arrows).
  • Anterior Teeth: Intrusion (yellow arrows).
  • Effect: Opens the deep overbite by modifying the vertical dimension.
  • Diagram: Illustrates the planned imbalance (thick red curved arrow) leading to controlled vertical movements.
  • Outcome: Deep overbite correction through extrusion of posterior teeth and intrusion of anterior teeth.

Summary

Group B anchorage allows for controlled space closure through balanced forces and moments. By adjusting the moments, orthodontists can achieve either translational movement or vertical adjustments, making it a versatile approach in clinical orthodontics.

Bimaxillary Dentoalveolar Protrusion: Traits and Orthodontic Correction

Bimaxillary protrusion is a condition characterized by protrusive and proclined upper and lower incisors with increased lip procumbency. It is commonly seen in African-American and Asian populations but can occur across all ethnic groups. Due to the negative perception of protrusive dentition and lips in many cultures, patients with bimaxillary protrusion often seek orthodontic treatment to improve their facial profiles. This guide summarizes key aspects of bimaxillary protrusion, including its etiology, pretreatment characteristics, treatment goals, and outcomes.

Etiology of Bimaxillary Protrusion

The etiology of bimaxillary protrusion is multifactorial, including:

  • Genetic Factors: Hereditary traits influencing facial and dental structures.
  • Environmental Factors:
    • Mouth breathing.
    • Tongue and lip habits.
    • Increased tongue volume.

Morphological Features

Keating’s study on Caucasian patients identified the following cephalometric traits:

FeatureObservation
Posterior cranial baseShorter
MaxillaLonger and more prognathic
Skeletal patternMild Class II
Upper and posterior face heightSmaller
Facial planesDivergent
Soft tissue profileProcumbent with a low lip line

Pretreatment Characteristics

Cephalometric Traits

Patients with bimaxillary protrusion exhibit the following pretreatment characteristics:

TraitObservation
Upper and lower incisor proclinationIncreased (2-3 SD above mixed racial norms)
Vertical growth patternsIncreased lower anterior face height
Mandibular plane angleElevated
Alveolar heightsIncreased

Soft Tissue Features

  • Lip Position:
    • Upper and lower lips are ahead of the E-plane.
    • Lower lip: 6.0 mm ahead (Keating’s Caucasian sample).
    • Upper lip: 1.0 mm ahead (less than Keating’s 3.4 mm).
  • Nasolabial Angle:
    • Found to be 94° (1 SD more acute than mixed racial norms).
    • Tan’s study on Chinese patients reported an even more acute angle (86.6°).
  • Lip Thickness:
    • Increased, likely due to a higher proportion of African-American patients in the study.

Alveolar Morphology

  • Alveolar Width: Reduced compared to Handelman’s norms.
  • Alveolar Height: Increased, consistent with vertical facial growth patterns.
  • Thin and elongated alveolus may limit retraction mechanics and necessitate surgical osteotomies in severe cases.

Orthodontic Treatment Goals

The primary objectives of treating bimaxillary protrusion include:

  • Dental Goals:
    • Retraction and retroclination of maxillary and mandibular incisors.
    • Reduction in incisor proclination and protrusion.
  • Soft Tissue Goals:
    • Decrease in lip procumbency and convexity.
    • Improvement in the nasolabial angle.
  • Mechanics Used:
    • Extraction of four first premolars.
    • Retraction using maximum anchorage mechanics.

Flowchart: Treatment Goals and Process

1. Initial Diagnosis → 2. Extraction of Four Premolars → 3. Retraction of Incisors → 4. Profile Improvement

Treatment Outcomes

Dental and Skeletal Changes

ParameterObservation
Interincisal angleIncreased significantly
Incisor inclinationDecreased significantly
Anteroposterior incisor positionReduced significantly (P < .001)

Soft Tissue Changes

  • Upper Lip Retraction:
    • Ratio of upper incisor retraction to upper lip retraction: 2.2:1 (similar to Chiasson and Hershey).
    • Nasolabial angle: Increased significantly (P < .02).
  • Variability:
    • Lip response depends on factors like interlabial gap, lip redundancy, and musculature quality.

Vertical Dimension

  • No significant changes in lower anterior face height or mandibular plane angle, indicating that treatment mechanics do not affect the vertical dimension.

Comparing Forsus FRD and PowerScope: A Cephalometric Analysis

Introduction
Malocclusion, characterized by changes in teeth positioning and skeletal growth, represents a global public health concern.

  • Historical Context: Correction attempts date back to at least 1000 BC.
  • Prevalence: Class II malocclusion affects one-third of the population and is categorized as skeletal or dental in origin.
  • Etiology:
    • Only 20% of Class II Division 1 cases are due to maxillary protrusion.
    • The majority stem from mandibular retrusion.

This prevalence has led to the development of functional appliances aimed at stimulating mandibular growth. These devices are divided into removable and fixed functional appliances.

Fixed Functional Appliances

  • Types:
    • Rigid: Herbst appliance, MARA (Mandibular Advancement Repositioning Appliance).
    • Flexible: Jasper Jumper, Scandee tubular jumpers.
    • Hybrid: Forsus Fatigue Resistant Device (FFRD).
  • Forsus Fatigue Resistant Device (FFRD):
    • A telescoping spring mechanism for Class II correction.
    • Provides moderate patient tolerance with initial discomfort that subsides over time.
  • PowerScope Appliance:
    • Latest addition, introduced by Dr. Andy Hayes in 2016 in collaboration with American Orthodontics.
    • Features a telescopic mechanism with a nickel-titanium (NiTi) spring delivering 260 g constant force.
    • Designed as a preassembled, one-size-fits-all appliance for easy chairside application.

Study Rationale
While Forsus FRD is extensively studied, limited literature evaluates and compares the skeletal, dental, and soft tissue effects of PowerScope. This study bridges that gap by conducting a cephalometric evaluation and comparison of these two fixed functional appliances.

Results and Discussion Summary

AspectParameterForsus FRDPowerScopeComparison
Skeletal ChangesLower gonial angleDecreased significantly (P = .005)Increased (P = .009)Better effect in Forsus.
SNADecreased (P = .037)No significant changeForsus > PowerScope (P = .026).
SNBIncreased significantly (P < .001)Increased significantly (P < .001)Both effective.
ANBDecreased significantly (P < .001)Decreased significantly (P < .001)Both effective.
Wits, beta, and YEN anglesIncreased significantly (P < .001)Increased significantly (P < .001)Both effective.
NA‖HPDecreased significantly (P = .001)Decreased (P = .022)Both effective.
NB‖HPIncreased significantly (P < .001)Increased significantly (P < .001)Both effective.
Effective mandibular lengthIncreased (P < .001)Increased significantlyBoth effective.
Dentoalveolar ChangesL1-NB and L1-NPogIncreased significantly (P = .013, P = .014)Mild increasePowerScope > Forsus. (P = .011 for IMPA).
IMPA (Incisor mandibular plane angle)Increased significantly (P = .001)Increased significantlyPowerScope > Forsus.
U1-SN and U1-NANo significant changeDecreased (P = .021, P = .026)PowerScope effective due to distalization effect.
Interincisal angleDecreased significantly (P = .034)No significant changeForsus effective.
Soft Tissue ChangesFacial convexityDecreased significantly (P < .001)Decreased significantly (P < .001)PowerScope > Forsus (P = .044).
Nasolabial angleIncreased significantly (P = .035)Mild increaseForsus > PowerScope (P = .017).
Upper lip strainDecreased significantly (P < .001)Decreased significantly (P = .012)Both effective.
Upper lip-to-E lineInsignificant changeIncreased significantly (P = .009)PowerScope > Forsus.
Overjet/OverbiteReductionHighly significant (P < .001)Highly significant (P < .001)No significant intergroup difference (P > .05).

Key Comparisons

AspectForsus FRDPowerScope
Skeletal ChangesMore maxillary retrusion, greater SNB increaseGreater impact on mandibular advancement
DentoalveolarSignificant lower incisor proclinationBetter upper incisor inclination correction
Soft TissueGreater improvement in nasolabial angleBetter profile correction (facial convexity)
Overjet/OverbiteEffectiveEffective

Conclusions

Both appliances are effective in correcting Class II discrepancies caused by retrognathic mandibles. However:

  • Forsus FRD is superior in achieving skeletal changes, particularly maxillary retrusion and mandibular advancement.
  • PowerScope shows more pronounced effects on dentoalveolar and soft tissue parameters, especially upper incisor inclination correction and facial convexity improvement.

Exploring the Impact of Class II Elastics on the Functional Occlusal Plane: What Every Orthodontic Student Should Know

In the world of orthodontics, Class II intermaxillary elastics have stood the test of time as a cornerstone of clinical treatment. Since their introduction by Maynard in 1843 and subsequent refinement by Henry A. Baker in the late 19th century, these small but mighty elastics have been indispensable in managing malocclusions. For orthodontic students, understanding their effects, particularly on the functional occlusal plane (FOP), is essential for mastering treatment planning and clinical decision-making.

Why Does the Functional Occlusal Plane Matter?

The occlusal plane is more than a line connecting occlusal surfaces; it’s a fundamental aspect of facial esthetics, function, and skeletal harmony. Its orientation relative to cranial and mandibular planes influences:

  • Maxillary and mandibular skeletal relationships
  • Facial forms and esthetics
  • Occlusal function

Alterations in the occlusal plane, whether due to growth or treatment, can significantly affect treatment outcomes and post-treatment stability. As orthodontic practitioners, it’s crucial to strike a balance between functional correction and maintaining or improving esthetic harmony.

The Role of Class II Elastics

Class II elastics have long been used to address sagittal and vertical discrepancies, including the correction of Class II malocclusions and open bites. While effective, their reciprocal forces can induce both desirable and adverse effects. Reports have suggested that Class II elastics might steepen the occlusal plane, potentially leading to instability or relapse post-treatment. However, these findings were often based on small sample sizes or non-growing patients, leaving gaps in our understanding of their effects during growth phases.

What Did This Study Investigate?

To address these gaps, a recent study analyzed the effects of Class II elastics on FOP in growing patients aged 11 to 16 years. Here’s what the researchers aimed to find out:

  1. Does the use of Class II elastics steepen the FOP?
  2. Are these changes more pronounced in extraction cases or patients with high-angle skeletal patterns?
  3. Do these changes persist or relapse after treatment?

Key Findings to Remember

1. Angular Changes in the FOP

  • FOP-SN and FOP-FH: Decreased significantly from pretreatment (T0) to post-treatment (T1) and continued to decrease 1 year post-treatment (T2).
  • FOP-MP: Increased from T0 to T1, likely as a reciprocal effect of FOP-SN/FH changes.

2. Influence of Skeletal Patterns

  • Hyperdivergent patients showed the largest FOP angles across all time points, while hypodivergent patients had the smallest.
  • Despite these differences, changes in FOP were consistent across skeletal types, indicating that Class II elastics affect all growth patterns similarly.

3. Treatment Modalities: Extraction vs. Non-Extraction

  • Patients undergoing extraction treatment exhibited steeper initial FOP-MP angles, reflecting a preference to extract in such cases.
  • No significant differences were observed in FOP changes between extraction and non-extraction groups during or after treatment.

Clinical Implications for Students

  1. Normal Growth vs. Treatment Effects: The study suggests that changes in FOP may largely reflect normal growth patterns rather than direct effects of Class II elastics. This aligns with findings from Creekmore, Schudy, and Harris, emphasizing the importance of accounting for growth dynamics.
  2. Individualized Treatment Planning: While Class II elastics are versatile, their effects on the FOP and associated structures vary based on skeletal patterns and growth trends. Orthodontic treatment must be tailored to each patient’s unique craniofacial morphology.
  3. Extraction Considerations: Although extraction cases may present steeper occlusal planes initially, the use of Class II elastics does not appear to exacerbate this steepness.

Takeaways for Orthodontic Students

  • Class II elastics remain a reliable tool for addressing Class II malocclusions, but understanding their nuanced effects on the FOP is key to optimizing outcomes.
  • Growth patterns play a pivotal role in how the FOP evolves during treatment. Observing these changes in clinical practice can enhance your ability to predict and manage treatment outcomes.
  • Finally, always consider the interplay between function, esthetics, and stability when planning orthodontic interventions.

Class II elastics may be small, but their impact on treatment is anything but. With careful planning and an understanding of growth influences, you can wield this classic tool to achieve remarkable results in your future practice.

Bimaxillary Protrusion: Incisor + Lip Retraction and Nasolabial Angle

Bimaxillary protrusion is a common orthodontic condition marked by protrusive and proclined upper and lower incisors, coupled with increased lip prominence. While predominantly seen in African American and Asian populations, it is not limited to any single ethnic group. This condition often leads patients to seek orthodontic treatment due to the aesthetic concerns of protruding lips and dentition.

Soft Tissue and Hard Tissue Correlation

Orthodontic studies present two conflicting perspectives on the relationship between incisor retraction and lip position:

  1. Strong Correlation: Some studies demonstrate a direct relationship between incisor and lip retraction.
  2. Weak Correlation: Some studies suggest that soft tissue changes do not proportionally mirror dental movements due to variables like growth, lip tonicity, and anchorage.

Four retrospective studies on bimaxillary protrusion treatment provided valuable insights:

Study FindingsUpper Lip Retraction (mm)Lower Lip Retraction (mm)Nasolabial Angle Increase (°)
Caplan et al. (2009)3.02.4Not significant
Tan et al.2.72.010.5
Lew3.24.510.0
Bills et al.3.02.43.1

Incisor Retraction and Lip Retraction Ratios

StudyUpper Lip to Incisor RetractionLower Lip to Incisor Retraction
Caplan et al.1:1.41:1.2
Other Studies1:2.21:1.75

Clinical Implications

  • Four-premolar extractions effectively reduce lip procumbency in bimaxillary protrusion.
  • Nasolabial angle tends to increase post-treatment.

Molar Distalization: Buccal Appliances VS Palatal Appliances

Molar distalization is a crucial technique in orthodontics, particularly for patients with Class II malocclusion. Thanks to advancements in biomechanics, materials, and technology, orthodontists now have access to a variety of intramaxillary intraoral appliances that can apply light, continuous forces for effective molar distalization. These appliances have become a game-changer, providing us with more precise control and predictable results.

Types of Intramaxillary Appliances

The application of forces in molar distalization can come from two primary areas: the buccal or the palatal region. Depending on where the force is applied, appliances can be categorized into two broad groups:

  1. Buccal Force Application: These appliances apply force from the outside of the dental arch.
  2. Palatal Force Application: These appliances exert force from the roof of the mouth.

Additionally, the force mechanisms can be divided into two categories:

  • Friction-Free Mechanism: This type involves appliances like the pendulum, which are designed to move the molars without causing significant friction.
  • Sliding Mechanism: Appliances like nickel-titanium (NiTi) coil springs use a sliding mechanism to apply force, creating a more dynamic force delivery system.

Each of these appliance types has its own set of advantages and drawbacks, and comparing their efficiency in achieving molar distalization is key to making evidence-based treatment decisions. However, due to the limited number of randomized clinical trials, a meta-analysis is often not possible. That said, a comprehensive analysis of existing studies can still offer valuable insights into how these appliances work.

Treatment Outcomes: Overall Effects

When all intramaxillary appliances were considered together, some general findings emerged:

  • First Molar Movement: On average, first molars moved 2.9 mm distally, but this came with a 5.4° of distal tipping.
  • Incisor Movement: The incisors shifted mesially by 1.8 mm with 3.6° of mesial tipping.
  • Premolar Movement: Premolars showed a mesial shift of 1.7 mm, though tipping was less pronounced.

Vertical movements were generally extrusive for incisors and premolars, with incisors showing an average extrusion of 0.4 mm and premolars 1.1 mm. Interestingly, molar vertical movements were not statistically significant, indicating that the main effect on molars was distal movement and tipping rather than vertical displacement.

Treatment Effects: Buccal vs. Palatal Appliances

Now, let’s delve into the specific effects of buccal and palatal appliances. These results highlight the different ways these appliances move teeth:

  • Buccal Appliances:
    • Molar Movement: Molar distal movement was 2.6 mm, with a more significant tipping of 8.3°.
    • Incisor Movement: Incisors moved mesially by 1.9 mm with 5.0° of mesial tipping.
    • Premolar Movement: Premolars demonstrated a 2.0 mm mesial shift, accompanied by 7.0° of mesial tipping.
    • Vertical Movement: Premolars showed a slight extrusion of 0.7 mm, while incisors had a more modest extrusion of 0.2 mm.
  • Palatal Appliances:
    • Molar Movement: Molar distalization was slightly more pronounced, with 3.1 mm of movement and 3.6° of tipping.
    • Incisor Movement: Incisors exhibited a mesial shift of 1.8 mm with 2.9° of mesial tipping.
    • Premolar Movement: Premolars moved mesially by 1.3 mm with less tipping than buccal appliances.
    • Vertical Movement: The extrusion for incisors was 0.7 mm, and premolars showed an extrusion of 1.0 mm.

Molar Distalization and Anchorage Loss

The primary effect of noncompliance intramaxillary appliances is molar distalization, which is typically achieved through a combination of crown distal movement and tipping. While distalization is the goal, a common side effect observed is loss of anchorage. This loss can be seen in the mesial movements and extrusions of incisors and premolars.

Key Findings:

  • Molars: Show a combination of distal crown movement and distal tipping.
  • Incisors: Exhibit mesial movement, tipping, and extrusion.
  • Premolars: Display mesial crown movement and extrusion.

As with any treatment modality, careful planning is required to manage these unintended side effects and achieve the best possible clinical outcomes.

Buccal vs. Palatal Appliances: Tipping and Force Mechanics

One interesting observation in the study was the difference in tipping effects between buccal and palatal acting appliances. Palatal appliances consistently resulted in less tipping of teeth compared to buccal appliances, as indicated by the non-overlapping confidence intervals.

Why the Difference?

The key reason for this difference lies in the moment arm of the force. In palatal appliances, the line of action of the force is closer to the center of resistance of the tooth, leading to less tipping and more controlled molar movement.

Table 1: Comparison of Tipping between Buccal and Palatal Appliances

Appliance TypeMolars Distal Movement (mm)Molars Tipping (°)Incisor Mesial Movement (mm)Incisor Tipping (°)Premolar Mesial Movement (mm)Premolar Tipping (°)
Buccal Appliances2.68.31.95.02.07.0
Palatal Appliances3.13.61.82.91.33.0

This table highlights the greater tipping observed with buccal appliances compared to palatal appliances, as well as the differences in molar distalization and mesial movement of incisors and premolars.

The Nance Button: Anchorage Considerations

Another point of discussion is the use of the Nance button to reinforce anterior anchorage during molar distalization. While it can support anchorage to some extent, it does not provide absolute anchorage. This is because the Nance button, as part of the anchorage unit, cannot completely resist mesial forces during molar distalization. Clinically, this often results in an increased overjet and proclination of maxillary incisors.

Clinical Tip:

For patients already presenting with an increased overjet, orthodontists must proceed with caution when prescribing these appliances. These cases may require additional measures to control the overjet and manage incisor proclination.

The Pendulum Appliance: A Look at Tipping and Movement

The pendulum appliance, a popular friction-free appliance, was noted in the study to cause the greatest distal tipping of molars. However, this tipping was correlated with a larger amount of distal crown movement. Interestingly, this tipping can often be corrected with the use of molar uprighting bends.

Table 2: Molar Distalization and Tipping with the Pendulum Appliance

Movement TypeMolar Distal Movement (mm)Molar Tipping (°)
Pendulum Appliance3.49.0

This table shows that the pendulum appliance can achieve significant molar distalization but at the cost of increased tipping. These tipping movements can be addressed with molar uprighting bends, which can help reduce the tipping angle.

Factors Affecting Molar Distalization

Several factors can influence the effectiveness of molar distalization, including:

  1. Teeth Used for Anchorage: Different anchorage setups can affect the extent of distal movement.
  2. The Type of Appliance Used: Whether the appliance uses a sliding mechanism or a friction-free mechanism plays a role.
  3. Patient Factors: Age, initial molar relationships, and the eruption of second and third molars all contribute to how effectively molars are distalized.

In studies that focus on growing patients, mean ages ranged from 11.2 to 14.9 years, which is crucial because the growth phase can significantly impact the effectiveness of treatment. For example, molar distalization is often more effective before the second molars have erupted. When second molars are erupted, more force may be required, and the treatment time may increase.

Table 3: Influence of Molar Eruption on Distalization Efficiency

ConditionMolar Distalization Efficiency
Second Molars UneruptedMore efficient, faster results
Second Molars EruptedLess efficient, longer treatment

Understanding and Managing Angle’s Class I Malocclusion in Clinical Practice

Angle’s Class I malocclusion is one of the most common types of dental misalignment encountered in clinical practice. It refers to a situation where the upper and lower teeth are generally aligned, but various issues such as crowding, spacing, bidental protrusion, vertical problems (deep bite or open bite), and transverse issues (crossbite or scissor bite) can arise. The good news is that these issues are typically easier to treat compared to more complex malocclusions, giving patients a higher chance of successful outcomes.

The Role of Growth in Achieving Class I Malocclusion

It’s important to understand that many of us begin with a skeletal Class II pattern during early development. With favorable growth, the individual’s skeletal structure may gradually transition into a skeletal Class I relationship. For example, a patient presenting with a mild facial convexity in mixed dentition can often be expected to develop a straighter profile as they continue to grow. This process occurs as growth in all three spatial planes—vertical, transverse, and sagittal—happens synchronously, ultimately resulting in a Class I skeletal configuration.

As this growth progresses, the facial profile becomes less convex, giving the appearance of a more balanced, harmonious face. Therefore, many orthodontic cases that are deemed successful are a combination of favorable natural growth and orthodontic intervention.

Focus on Intraarch Alignment and Interarch Occlusion

In patients with Angle’s Class I malocclusion, the anteroposterior skeletal relationship is normal. The primary goal of orthodontic treatment in these cases is to focus on correcting intraarch alignment and interarch occlusal relations. Treatment options vary depending on the individual case and may include:

  • Extractions: Often used to create space when necessary.
  • Non-extraction approaches: These can include slenderization (reducing the size of teeth), expansion (widening the dental arch), distalization (moving the back teeth backwards), derotation (correcting the rotation of posterior teeth), and proclination (moving retroclined anterior teeth forward).

Managing Specific Class I Malocclusion Issues

Crowding and Spacing: Spacing issues in the dental arch can occur for various reasons, such as hypodontia (missing teeth) or microdontia (abnormally small teeth). Hypodontia often affects the maxillary lateral incisors and mandibular premolars. In these cases, the orthodontist must decide whether to open space for prosthetic replacements or to close the space orthodontically. On the other hand, microdontia can be managed through space redistribution and the aesthetic build-up of smaller teeth.

Bidental Protrusion: Bidental protrusion is another common concern seen in patients with a Class I skeletal base. This condition can often be efficiently managed with premolar extractions, which help reduce the protrusion and bring the teeth into better alignment.

Vertical and Transverse Problems: While Class I malocclusion is generally associated with a normal anteroposterior skeletal relationship, vertical (deep bite or open bite) and transverse issues (crossbite or scissor bite) may still be present. These concerns are often addressed in subsequent stages of orthodontic treatment.

Conclusion

Angle’s Class I malocclusion is a frequent and treatable condition seen in orthodontic practice. The successful outcomes often stem from a combination of natural growth and targeted orthodontic interventions. Whether addressing crowding, spacing, bidental protrusion, or vertical and transverse problems, orthodontists can employ various techniques such as extractions, slenderization, expansion, and more to achieve optimal results. Understanding the underlying growth patterns and employing the right treatment plan is key to ensuring that patients achieve a balanced, functional, and aesthetically pleasing smile.

Alt-RAMEC Explained: Maxillary Expansion Technique

Class III Malocclusion and Maxillary Retrusion

  • Causes: Class III malocclusions can arise from mandibular protrusion, maxillary retrusion, or both.
  • Studies on Maxillary Retrusion: Various studies report the contribution of maxillary retrusion to Class III malocclusions in individuals with normal mandibles, with percentages ranging between 19.5% and 37%.
  • Treatment Focus: This recognition has led to introducing treatments like the orthopedic facemask for maxillary protraction.

Alternate Rapid Maxillary Expansion and Constriction (Alt-RAMEC)

  • Protocol: Expands and contracts the maxilla alternately (1 mm/day for a week each, repeated for 7–9 weeks) using a two-hinged rapid maxillary expander.
  • Rationale: Mimics the rocking mechanism in tooth extraction, disarticulating circum-maxillary sutures without over-expansion.

Alt-RAMEC Protocol Details

  1. Activation Phase:
    • The expansion screw was turned twice daily at a rate of 0.20 mm per turn.
    • This phase lasted for 1 week, ensuring the maxilla was progressively expanded.
  2. Deactivation Phase:
    • The screw was then turned twice daily in reverse at a rate of 0.20 mm per turn.
    • This phase also lasted for 1 week, gradually constricting the maxilla back.
  3. Repetition:
    • The activation and deactivation sequence was repeated for a second cycle.
    • After each week-long activation or deactivation phase, the patients were examined to monitor proper opening or closing of the screw, ensuring precision in the procedure.
  4. Post-Protocol Guidance:
    • Following the completion of the Alt-RAMEC cycles, patients were instructed to wear the Reverse Headgear (RH). This is a common adjunct in orthopedic facemask therapy designed to enhance maxillary protraction after the suture disarticulation achieved by Alt-RAMEC.

Results of Alt-RAMEC

  • Comparison with RPE:
    • Alt-RAMEC: Achieved an average anterior movement of point A by 5.8 mm in cleft patients over 9 weeks.
    • RPE: Achieved only 2.6 mm movement after 1 week.
    • Suture Opening: Experimental studies confirmed that Alt-RAMEC opens circum-maxillary sutures more extensively than 1 week of RPE.

Clinical Implications

ParameterA/D-RPE GroupRPE GroupComparison with Previous Studies
Maxillary Advancement (Point A)4.13 mm (T3)2.33 mm (T3)Greater movement in A/D-RPE group, similar to Liou and Tsai (2005) findings.
Anterior Movement of Point ASignificant difference (greater in A/D-RPE)Observed, but lesser than A/D-RPELiou and Tsai (2005), Merwin et al. (1997), Kapust et al. (1998), Sung & Baik (1998) showed comparable results to RPE group.
Mandibular RotationPosterior rotation observedPosterior rotation observedConsistent with previous studies (Merwin et al., 1997; Kapust et al., 1998).
Anterior Face Height IncreaseObservedObservedFindings align with previous studies.
Maxillary Plane AngleDecrease of 1.53 degrees (T3)Decrease observedA/D-RPE showed significant decrease, consistent with previous studies.
SNA Angle IncreaseSignificant difference (greater in A/D-RPE)ObservedA/D-RPE resulted in more significant SNA angle increase compared to RPE group.
ANB Angle IncreaseSignificant difference (greater in A/D-RPE)ObservedA/D-RPE showed more significant increase in ANB angle.
Overjet CorrectionGreater correction in A/D-RPE92.5% skeletal, 7.5% incisor tippingA/D-RPE showed a higher skeletal contribution (93%) vs. RPE (92.5%).
Skeletal vs. Dental Contribution to Overjet93% skeletal, 7% dental92.5% skeletal, 7.5% dentalA/D-RPE showed a higher skeletal contribution (57.9% maxillary, 35.1% mandibular).
Soft Tissue Profile ChangesMore pronounced in A/D-RPE (upper lip anterior, lower lip posterior)Observed (less pronounced)Profile improvement observed in both groups; A/D-RPE showed more pronounced soft tissue changes.
RH Usage During Treatment16-18 hours/day (initial 6 months), 12 hours/day (2nd 6 months), 6 hours/day (passive phase)Varied by study, typically used for 14 hours/daySimilar to recommendations of Saadia and Torres (2000) and others (Macdonald et al., 1999).
RelapseNo significant relapse observedNo significant relapse observedConsistent with previous studies (Macdonald et al., 1999; Vaughn et al., 2005).

Burning Palate and Chest Pain: Connecting Oral Health to Systemic Risk

Clinical view of the patient’s palate. Burning Mouth Syndrome or Something More? A Case of Dual Diagnosis

An 80-year-old patient presents to the office with a chief complaint of a continuous burning feeling on his palate. Upon examination you find that the patient is extremely sensitive.When you finish your examination, the patient complains of sudden chest pain. He starts to sweat and has labored breathing.

Q: What is your diagnosis of the patient?

  • Medical: There are a number of possibilities for the patient to have chest pain and labored breathing. The patient might be experiencing an acute myocardial infarction, hyperventilation, or angina pectoris.
  • Dental: The patient has a Candida species infection, which is a gingival disease of fungal origin. It is also known as atrophic (erythematous) candidiasis.

Q: How will you manage the patient if he is having a myo-cardial infarction?

  1. Stop the dental procedure
  2. Administer oxygen to the patient at 4 to 6 liters per minute
  3. Call emergency medical services (EMS) immediately.
  4. Administer nitroglycerin from the emergency kit (if pain continues, most likely not angina)
  5. Administer aspirin (fibrinolytic properties):
    Give the patient 325 mg of non-enteric-coated aspirin to chew if they have no contraindications (e.g., allergies or bleeding disorders)
  6. Monitor vital signs
  7. Keep the patient in a comfortable seated position to minimize strain on the heart.
  8. Manage the patient’s pain with opioids (morphine) or nitrous oxide

Q: What is your approach to treating the dental condition of this patient?

First treat the condition with a topical antifungal (eg, nystatin or clotrimazole troches) applied to the tissue side of the denture four to six times a day for 2 to 3 weeks. If the fungal infection persists,treat the patient with 100 mg fluconazole daily.

@dr.mehnaz


REFERENCESPERIODONTAL REVIEW : A STUDY GUIDE / DEBORAH TERMEIE.

Decoding Oral Malodor: Managing a Mandibular Molar Abscess in a Medically Complex Patient

When Bad Breath Signals Trouble: A Case of Mandibular Molar Abscess

The patient is a 65-year-old man complaining of oral malodor. His dentist referred him to you to access the mandibular right second molar because of swelling, pus, and soreness. When he sits in your chair, he seems disoriented and irritable.When you look in his mouth, you find generalized inflammation of the gingiva and an abscess on the buccal aspect of the mandibular right second molar with suppuration. Charting demonstrates an 8-mm facial pocket and 6-mm palatal and interproximal pockets.

Q: What is your diagnosis of the patient?

Medical:

There are a number of reasons for the patient to appear dazed and irritable:

  • Hypoglycemia or hyperglycemia
  • Alcohol or drug overdose
  • Hyperthyroidism or hypothyroidism
  • Cerebrovascular incident

Dental:

  • The patient may have diabetes mellitus–associated gingivitis related to the endocrine system, under the heading of gingival diseases modified by systemic diseases, which is a subcategory of dental plaque–induced gingival diseases.
  • The patient has a periodontal abscess, which is a subclassification of abscesses of the periodontium.

Q: What could have led to the abscess formation?

  • Diabetes: According to Bjelland et al,18 multiple periodontal abscesses may result from uncontrolled hyperglycemia. Rees19 listed multiple or recurrent periodontal abscesses among the possible indications of undiagnosed or poorly controlled diabetes mellitus.
  • The abscess may also be caused by a preexisting periodontal pocket in association with bacteria at the depth of the pocket.
  • A foreign body can also cause a periodontal abscess.

Q: How will you treat the periodontal abscess?

  • I would ask the patient if he has seen his physician recently and whether he knows his hemoglobin A1c levels to determine if the abscess may be associated with diabetes (only his medical doctor can make that diagnosis).
  • An incision at a 90-degree angle to the long axis of the tooth will drain the exudate.Without removal of the cause (foreign body, bacteria, or calculus), the abscess will recur. If this is not possible, extraction might be necessary.
  • Antibiotics and analgesics should be prescribed. A follow-up with a dentist is also needed.
  • Saline Rinse: Advise warm saline rinses to reduce discomfort and promote healing.

Dentowesome | @dr.mehnaz


References: Periodontal review : a study guide / Deborah Termeie.