Relapse of orthodontically corrected deepbites in accordance with growth pattern

Long-term stability of curve of Spee depth among orthodontically treated patients: A retrospective longitudinal study

OBJECTIVE

The curve of Spee is deemed important characteristic of the dentition for a balanced occlusion and distribution of masticatory forces, while orthodontic levelling of an accentuated curve of Spee is generally included as a treatment goal for deepbite correction. However, relapse is often seen and can be problematic.

METHODS

A retrospective longitudinal study of predominantly young patients with a deep curve of Spee, who had been treated orthodontically with 0.018"-slot Edgewise fixed appliances, was performed. The depth of the curve of Spee was digitally measured before treatment (T1), at debond (T2), and an average of 7 years post-debond (T3) and analysed statistically at 5%.

RESULTS

A total of 157 patients were included (56.7% female; 11.6-year-old at T1), 16.6% of which were treated with premolars extractions. Non-extraction treatment reduced the curve of Spee at the first premolar from 1.87 mm (T1) to 0.22 mm (T2), which relapsed 0.12 mm (T3; P = .04). The respective depths for the second premolar were 2.0 mm (T1), reduced to 0.80 mm (T2). No significant relapse was seen for the second premolar (0.08 mm; P > .05) or the first permanent molar (0.06 mm; P > .05). No overall significant differences in absolute relapse were seen between extraction and non-extraction patients, but premolar extractions were associated with less clinically relevant relapse at the first molar (odds ratio 0.27; 95%-confidence interval 0.08-0.88; P = .003).

CONCLUSION

Steep curves of Spee can be satisfactorily levelled orthodontically with satisfactory stability in the long term, while premolar extractions might be associated with less relapse.

Comprehensive Deciphering the Complexity of the Deep Bite: Insight from Animal Model to Human Subjects

Deep bite is a malocclusion phenotype, defined as the misalignment in the vertical dimension of teeth and jaws and characterized by excessive overlap of the upper front teeth over the lower front teeth. Numerous factors, including genetics, environmental factors, and behavioral ones, might contribute to deep bite. In this study, we discuss the current clinical treatment strategies for deep bite, summarize the already published findings of genetic analysis associated with this complex phenotype, and their constraints. Finally, we propose a comprehensive roadmap to facilitate investigations for determining the genetic bases of this complex phenotype development. Initially, human deep bite phenotype, genetics of human deep bite, the prevalence of human deep bite, diagnosis, and treatment of human deep bite were the search terms for published publications. Here, we discuss these findings and their limitations and our view on future strategies for studying the genetic bases of this complex phenotype. New preventative and treatment methods for this widespread dental issue can be developed with the help of an understanding of the genetic and epigenetic variables that influence malocclusion. Additionally, malocclusion treatment may benefit from technological developments like 3D printing and computer-aided design and manufacture (CAD/CAM). These technologies enable the development of personalized surgical and orthodontic guidelines, enhancing the accuracy and effectiveness of treatment. Overall, the most significant results for the patient can only be achieved with a customized treatment plan created by an experienced orthodontic professional. To design a plan that meets the patient's specific requirements and expectations, open communication between the patient and the orthodontist is essential. Here, we propose to conduct a genome-wide association study (GWAS), RNAseq analysis, integrating GWAS and expression quantitative trait loci (eQTL), micro and small RNA, and long noncoding RNA analysis in tissues associated with deep bite malocclusion in human, and complement it by the same approaches in the collaborative cross (CC) mouse model which offer a novel platform for identifying genetic factors as a cause of deep bite in mice, and subsequently can then be translated to humans. An additional direct outcome of this study is discovering novel genetic elements to advance our knowledge of how this malocclusion phenotype develops and open the venue for early identification of patients carrying the susceptible genetic factors so that we can offer early prevention and treatment strategies, a step towards applying a personalized medicine approach.

Leveling the curve of Spee: Comparison between continuous archwire treatment and Invisalign system: A retrospective study

INTRODUCTION

The purpose of this study was to evaluate and compare leveling of the curve of Spee (COS) achieved by traditional fixed appliances and Invisalign clear aligners (Align Technology, Santa Clara, Calif).

METHODS

This retrospective study involved 2 groups of subjects with an increased COS depth. Patients treated with the Invisalign system (I group) and patients treated with the standard edgewise full-fixed appliance (F group). The I group included 30 subjects (13 males, 17 females; mean age, 24 years 5 months ± 19 months). The F group included 32 subjects (12 males, 20 females; mean age, 22 years 4 months ± 21 months). The 2 groups were matched for sex, age, vertical pattern, and observation period. Pretreatment (T0) and posttreatment (T1) lateral cephalograms were analyzed. COS depth was measured on digital dental casts. The intragroup variation between T0 and T1 was analyzed with a paired t test. The intergroup variation was evaluated using an unpaired t test.

RESULTS

The leveling of COS was statistically significant, comparing T0 and T1 within the groups. The F group presented a statistically significant extrusion of posterior teeth, with a flaring of the mandibular incisors. The I group showed a statistically significant intrusion of the mandibular incisors, with excellent control in the proclination of incisors during the intrusion movement.

CONCLUSIONS

Traditional continuous archwire treatment and the Invisalign system effectively level the COS.

Association of Craniofacial Patterns with the Curve of Spee and the Time Required for Orthodontic Levelling

The curve of Spee (CoS) is an important parameter for an individualized treatment plan. The available information regarding a potential association of the depth of the curve of Spee with various skeletal craniofacial characteristics is conflicting and it is also unknown whether certain craniofacial parameters affect the duration of the levelling phase of orthodontic treatment. A prospective sample of 32 patients with mild to moderate crowding that underwent orthodontic treatment with full fixed appliances was used to study these topics. The craniofacial characteristics were captured on pre-treatment lateral cephalometric radiographs and measurements of the CoS were performed on the initial 3D digital dental models using the Viewbox 4 software. Non-parametric statistics and Spearman’s correlations were applied. Weak negative correlations were detected between the CoS depth and the SNA and SNB angles. There was no other association between the CoS and craniofacial parameters, including various anteroposterior measurements. Furthermore, there was no significant association of any craniofacial parameter with the duration of the levelling. Contrary to certain clinical beliefs, it can be argued that the craniofacial characteristics are not associated with the CoS and the time required for its levelling in subjects with moderate pre-treatment CoS depth.

Survival and failure rate of lower lingual bonded retainers: a retrospective cohort evaluation

OBJECTIVE

The objectives of the study were to evaluate the survival rates for lower lingual retainers (LLRs) and to establish a correlation between patients' treatment-related factors (age, sex, malocclusion, appliance used for treatment, teeth bonded, retention protocols) to the survival of LLRs.

MATERIALS AND METHODS

A total of 765 subjects [474 females and 291 males: mean age = 24.29 ± 10.67 years] between 2013 and 2022 were included. A customized data collection form was utilized to gather the data from the electronic health record (EHR) of subjects. Patient-related factors, crowding or spacing, deep bite or open bite and duration of treatment were extracted from patients' files. Kaplan-Meier estimator was used for the survival function, whereas Cox proportional hazards regression models were used to associate risk factors with retainer survival.

RESULTS

328 (42.9%) subjects had their LLRs failed, and the survival period was on average 17.37 ± 22.85 months. On the other hand, the follow-up period for the retainers that did not fail was on average 47.19 ± 23.66 months. 192 (28.3%) subjects had segment failure (retainer detached from 3 teeth or less), while 51 (7.5%) subjects had failures in more than 3 teeth (complete). None of the evaluated clinical variables were significantly associated with LLRs failure except for the bite category (P = .013) and the appliance used for treatment (P < .001).

CONCLUSION

Success rate for LLRs was 57.1% over 47.19 months, failure rate was 42.9% over 17.37 months. The presence of deep bite and treatment with aligners were significantly associated with increased failure rate.

Can Botulinum Toxin-A Contribute to Reconstructing the Physiological Homeostasis of the Masticatory Complex in Short-Faced Patients during Occlusal Therapy? A Prospective Pilot Study

The physiological homeostasis of the masticatory complex in short-faced patients is too robust to be disintegrated and reconstructed due to the powerful masseter muscle. This study innovatively introduced the botulinum toxin-A (BTX-A) into the field of dental occlusal treatment, providing a novel and minimally invasive therapy perspective for the two major clinical problems in these patients (low treatment efficiency and high rates of complications). In total, 10 adult patients with skeletal low angle seeking occlusal treatment (age: 27.0 ± 6.1 years; 4 males and 6 females) were administered 30−50 U of BTX-A in each masseter muscle and evaluated before and 3 months after injection based on cone-beam computed tomography (CBCT). We found a significant reduction in the thickness of the masseter muscle (MMT) (p < 0.0001). With regards to occlusion, we found a significant increase in the height of the maxillary second molar (U7-PP) (p < 0.05) with significantly flattened occlusal curves (the curve of Spee [COS] (p < 0.01), and the curve of Wilson [COW] (p < 0.05)). Furthermore, the variations in the temporomandibular joint exhibited a significant reduction in the anterior joint space (AJS) (p < 0.05) and superior joint space (SJS) (p < 0.05). In addition, the correlation analysis of the masticatory complex provided the basis for the following multiple regression equation: MMT = 10.08 − 0.11 COW + 2.73 AJS. The findings from our pilot study indicate that BTX-A, as a new adjuvant treatment attempt of occlusal therapy for short-faced patients, can provide a more favorable muscular environment for subsequent occlusal therapy through the adjustment of the biting force and may contribute to the reconstruction of healthier homeostasis of the masticatory complex. However, further research is required to establish the reliability and validity of these findings.

Long-term stability of curve of Spee levelled with continuous archwires in subjects with different vertical patterns: a retrospective study

OBJECTIVES

The aim of the study was to evaluate the curve of Spee (COS) stability in patients treated with continuous archwires with different vertical patterns.

METHODS

The study sample consisted of 60 patients (28 males, 32 females; mean age 19.8 ± 1.4 years) presenting with COS depth of at least2 mm at baseline. For each subject, lateral cephalograms and dental casts were available before treatment (T1), at the end of orthodontic therapy (T2), and 2 years after the end of treatment (T3). All subjects were divided into three groups according to vertical facial patterns. Cephalometric parameters were used to evaluate the dental movements after treatment. COS depth was measured on digital casts. Mean differences between vertical facial subgroups were contrasted by means of analysis of variance test (P < 0.01).

RESULTS

In low-angle subjects, COS levelling occurred through advancement and intrusion of lower incisors, whereas in high-angle patients, the COS was flattened through extrusion and uprighting of lower posterior teeth. In the low-angle group, a significant relapse of lower incisors inclination was observed. Differently, the high-angle group exhibited a greater stability of COS obtained by stable extrusion of posterior teeth.

CONCLUSIONS

The long-term instability of flared incisors determined the relapse of overbite and COS depth in the low-angle group.

Dentoskeletal morphology in adults with Class I, Class II Division 1, or Class II Division 2 malocclusion with increased overbite

INTRODUCTION

The treatment options for adults with increased overbite are limited to dentoalveolar changes that camouflage the condition. Because of high relapse tendency, defining the problem area is important when creating a treatment plan. This study aimed to evaluate dentoskeletal morphology in skeletal Class I and II anomalies associated with Angle Class I, Class II Division 1 (Class II/1), and Class II Division 2 (Class II/2) malocclusions with increased overbite compared with normal occlusion.

METHODS

Pretreatment cephalograms of 306 patients (131 men, 175 women; overall ages 18-45 years) were evaluated. Four groups were constructed. Three groups had increased overbite (>4.5 mm): group 1 (n = 96) skeletal Class I (ANB = 0.5°-4°), group 2 (n = 85) skeletal Class II (ANB >4.5°) with Class II/1; and group 3 (n = 79) skeletal Class II with Class II/2 malocclusion. Group 4 as a control (n = 46) skeletal Class I normal overbite. Dental and skeletal characteristics of the groups were compared by sex. For statistical evaluations, analysis of variance followed by Tukey post hoc, Mann-Whitney U, and Kruskall-Wallis tests were used. Additionally correlation coefficients between overbite and skeletal/dental parameters were calculated.

RESULTS

Between sexes, with regard to skeletal parameters, the men had greater values in millimetric measurements, and the women had higher SN/GoGn values. Maxillary/mandibular molar heights and the mandibular incisor heights were higher in men. In group 1, decreased lower anterior facial height (LAFH), retrusive mandibular incisors, and increased interincisal degree were determined. The maxillary molars were intrusive, whereas the vertical position of the mandibular molars and incisors in both jaws were normal. In group 2, retrognathic mandible, increased LAFH and mandibular plane angle, extrusive maxillary/mandibular incisors, protrusive mandibular incisors, and decreased interincisal degree were found. In group 3, decreased LAFH, increased interincisal degree, and retrusive incisors in both jaws were determined. There were significant negative correlations between SN/GoGN, palatal plane, and overbite in group 2 and between ANS-SN and overbite in group 3, and positive correlation between interinsical angle and overbite in all increased overbite groups.

CONCLUSIONS

Dental morphology seems to be the main factor of increased overbite. Differences between groups were related primarily to inclinations and vertical positions of the incisors, rather than molar positions.

[Long-term stability and relapse of deep bite correction: a systematic review]

INTRODUCTION

 Deep overbite is one of the most common malocclusions and is the most difficult to treat successfully. The real challenge remains the stability of long-term deep overbite correction. A search through the scientific literature revealed only one systematic review on this subject. Given the recent publications on the stability of deep bite correction and the development of new processes designed to avoid relapse of these treatments, this one existing systematic review needs to be updated. The purpose of the present systematic review is to evaluate the long-term stability of deep overbite correction.

MATERIALS AND METHODS

 Electronic databases were searched and nonelectronic journals were manually explored for papers on long-term stability and relapse of deep overbite correction. Articles deemed appropriate for inclusion in this review were selected and analyzed. Their scientific quality was assessed and the data they contained were extracted and summarized.

RESULTS

 The rate of deep overbite relapse was 47.27%. Patients treated with the straight wire appliance showed a 67.74% relapse rate whereas those treated with the Ricketts biological progressive segmented mechanics appliance displayed a 30.38% rate. Subjects treated towards the end of adolescence presented a 14.3% rate of deep overbite relapse whereas those treated in their early teens or in adulthood had a deep overbite relapse rate of 30% and 30.8%, respectively. Intramuscular injections of botox helped obtain 100% stability in maxillofacial surgery to correct deep bite.

CONCLUSION

 Age at initiation of treatment and treatment technique are two factors impacting the long-term stability of deep overbite correction.

A prospective, split-mouth, clinical study of orthodontic titanium miniscrews with machined and acid-etched surfaces

OBJECTIVES

To determine whether the success rate and primary stability of surface-treated miniscrews differ from those of nontreated miniscrews.

MATERIALS AND METHODS

Patients who required one or more miniscrews for the same reason in each quadrant were recruited into a single-blinded, split-mouth, randomized, controlled trial with a 1:1 allocation ratio. Self-drilling miniscrews with two surface types were used: those with no surface treatment, and those with an acid-etched surface treatment. The cumulative success rate and primary stability of each type of miniscrew were examined, and factors potentially affecting the success and failure of miniscrews were investigated.

RESULTS

Forty patients were included in the study, with a total of 98 orthodontic miniscrews. The overall success rate was 88.8%, and the respective success rates for acid-etched and machined surface miniscrews were 91.8% and 85.7%. The respective mean insertion torques were 13.62 ± 5.95 N·cm and 13.38 ± 4 N·cm, and periotest values measured immediately after insertion were -0.50 ± 2.77 for acid-etched miniscrews and -0.28 ± 3.36 for machined surface miniscrews. There was no significant difference in the mean insertion torques and periotest values according to surface treatment and jaw.

CONCLUSIONS

Neither the success rate nor the primary stability of acid-etched surface miniscrews and machined surface miniscrews differed significantly. There is a high possibility that miniscrews will fall out in patients who have an open bite or those who require total distalization.

Leveling the curve of Spee with continuous archwire appliances in different vertical skeletal patterns: A retrospective study

INTRODUCTION

The aim of this study was to determine the effects of the leveling of the curve of Spee in subjects treated with preadjusted appliances in different skeletal vertical patterns.

METHODS

The study sample consisted of 90 white patients (39 male, 51 female; age, 19 years 4 months ± 1 year 9 months), with a curve of Spee of 2 mm or greater before treatment. They were categorized into 3 groups: low-angle group (30 subjects; 12 male, 18 female; age, 19 years 1 month ± 1 year 4 months), normal-angle group (30 subjects; 14 male, 16 female; age, 19 years 6 months ± 2 years 1 month), and high-angle group (30 subjects; 13 male, 17 female; age, 19 years 7 months ± 1 year 5 months) by their vertical facial types. Cephalometric parameters were used to evaluate the different dental movements after treatment. The curve of Spee was measured on digital dental casts. Analysis of variance was used to determine any differences between the changes in the groups with time.

RESULTS

For the skeletal variables, no significant modifications were found in the 3 groups. For the dentoalveolar variables, the low-angle group showed significant buccal movements and intrusion of the mandibular incisors. The high-angle group had greater extrusion of the posterior teeth associated with uprighting of the first and second molars.

CONCLUSIONS

In low-angle subjects, leveling of the curve of Spee occurs through buccal movement and intrusion of the mandibular incisors; in high-angle subjects, it occurs through extrusion and uprighting of the posterior teeth.

Prevalence of the Short Face Pattern in Individuals of Bauru-Brazil

Aim:

This study aimed at assessing the prevalence and severity of short face pattern in ethnically different individuals.

Material and Methods:

The sample comprised 4,409 Brazilians (2,192 females and 2,217 males), with a mean age of 13 years, enrolled in secondary schools in the municipality of Bauru. The sample inclusion criteria involved subjects with vertically impaired facial relationship based on excessive lip compression, when standing at natural head position, with the lips at rest. Once short face syndrome had been identified, the individuals were classified into three severity subtypes: mild, moderate, and severe. The sample was then stratified by ethnic background as White (Caucasoid), Black (African descent), Brown (mixed Caucasian–African descent), Yellow (Asian descent), and Brazilian Indian (Native Brazilian descent), using the Brazilian Institute of Geography and Statistics classification. The chi-square test at the 5% significance level was used to compare frequency ratios of individuals with vertically impaired facial relationships and across different ethnicities, according to severity.

Results:

The prevalence of short face pattern was 3.15%, as 1.11%, 1.99%, and 0.02% considered mild, moderate and severe subtypes, respectively. The severe subtype was rare (0.02%) and found only in one White individual. The White group had the highest relative frequency (45.53%) of the moderate subtype, followed by Brown individuals (43.40%). In the mild subtype, Yellow (68.08%) and White (62.21%) individuals showed similar and higher relative frequency values.

Conclusion:

The prevalence of short face pattern was 3.15%, and White individuals had the highest prevalence.

Botulinum toxin as a therapeutic agent to prevent relapse in deep bite patients

INTRODUCTION

The etiology of deep bite is multifactorial. One of the causes is increased muscular activity. This makes the treatment of deep bite malocclusions difficult and often results in relapse in many cases. In this work we compared patients with surgical orthognathic treatment only and surgical orthognathic treatment with additional injections of botulinum toxin after mandibular advancement for class II division 2 malocclusion.

MATERIAL AND METHODS

This is a prospective study. Adult patients were assessed pretreatment (T1), posttreatment (T2), and long-term after 1 year (T3). In total, 32 patients (mean age, 30.7 years; 23 women and 9 men) reached the study end point (T3); 24 patients were treated without botulinum toxin and 8 patients received preoperative injections of botulinum toxin.

RESULTS

Significant differences between both groups were observed, with a more stable result for the experimental group treated with botulinum toxin.

DISCUSSION

In a selective group of adult patients with a class II division II incisor relationship and with a class II skeletal base, botulinum toxin injections can effectively prevent relapse. This may present an alternative to a conventional myotomy.

Stability of deep-bite correction: A systematic review

OBJECTIVES

Deep bite occurs in about 15% to 20% of the US population. Currently, it is unknown which types of correction are most efficient or stable. The purpose of this systematic review was to investigate factors related to stability of deep-bite correction.

MATERIALS AND METHODS

An electronic search of 4 databases was performed from January 1, 1966 to June 27, 2012. Studies were considered for inclusion if they reported on deep bite samples that underwent orthodontic treatment in the permanent dentition. Records were required at the initial, posttreatment, and 1-year posttreatment times. Hand searching of reference lists of the included studies was performed. Data were abstracted using custom forms, and risk of bias was assessed using a modified Newcastle-Ottawa Scale.

RESULTS

Twenty-six studies met the inclusion criteria. Most were case series, with considerable potential for bias. The significant heterogeneity of the studies precluded meta-analyses, and only descriptive statistics and stratified comparisons were reported. On average, patients underwent significant overbite improvement during treatment, and most of the correction was maintained long-term. Across all studies, the mean initial overbite, posttreatment overbite, and long-term overbite were 5.3, 2.6, and 3.4 mm, respectively. Initial severity appeared to be related to long-term stability. However, this relationship was difficult to isolate from other factors. The length of follow-up did not appear to be related to the amount of relapse.

CONCLUSIONS

Although the quality of the current evidence is not high, patients with deep-bite malocclusion appear to undergo relatively successful treatment, and most of the correction appears to be stable.