Changes in alveolar bone support induced by the Herbst appliance: a tomographic evaluation

Changes in the alveolar bone morphology among different patterns of incisor inclination during the alignment phase in orthodontic treatment without premolar extraction

OBJECTIVE

The present study investigated bone remodelling in the upper and lower incisor regions depending on the inclination pattern during the alignment phase of orthodontic treatment (OT).

MATERIALS AND METHODS

This prospective clinical study included 71 patients undergoing OT without premolar extraction. Cone beam computed tomography scans were taken before and after the alignment phase and the changes in the inclination, alveolar bone height (ABH) and bone thickness (BT) at levels 2, 3, 4, 6, 8 and 9 mm starting from the cementoenamel junction (CEJ) were determined.

RESULTS

Teeth were divided into 'Retroinclination' (lingual crown inclination <0°), 'Proclination-low' (buccal crown inclination between 0° and 5°), or 'Proclination-high' (buccal crown inclination >5°). The alignment phase of OT resulted in ABH loss. The highest ABH loss in the maxilla was observed on the buccal side in the 'Proclination-high' and was 0.71 mm. ABH loss by 1.1 mm was observed in the mandible on the lingual side in the 'Retroinclination' group. The most significant changes in BT by up to 2 mm were observed at levels 6, 8 and 9 mm and these changes exhibited a moderate to strong correlation with the alterations in the inclination of individual incisors. At levels 2, 3 and 4 mm, the highest decrease in BT by up to 0.83 mm was observed on the palatal side of upper incisors in the 'Proclination-high' group.

CONCLUSION

The direction and amount of tooth inclination partially determine changes in the bone parameters during the alignment phase.

Comparison of Twin Block appliance and Herbst appliance in the treatment of Class II malocclusion among children: a meta-analysis

BACKGROUND

Our meta-analysis aimed to evaluate the efficacy of applying Herbst and Twin Block appliances in the treatment of Class II malocclusion among children.

METHODS

Databases, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), China VIP Database (VIP), and Wanfang were thoroughly searched from inception to August 9, 2023. The outcomes included skeletal, dental, and soft tissue changes. The weighted mean difference (WMD) was used as the effect indicator, and the effect size was expressed with a 95% confidence interval (CI). The heterogeneity of each outcome effect size was tested, and the heterogeneity statistic I2 ≥ 50% was analyzed by the random-effect model, otherwise, the fixed-effect model was conducted. Sensitivity analysis was performed.

RESULTS

A total of 12 studies involving 574 patients were included in this meta-analysis. Herbst appliance had a statistically significant increase in mandibular body length (WMD: 1.44, 95% CI: 0.93 to 1.96, P < 0.001) compared with the Twin Block appliance. More increases in angle and distance of L1 to mandibular plane (MP) were found in the Herbst appliance compared with the Twin Block appliance. Significant and greater improvements in molar relationship (WMD: 0.79, 95% CI: 0.28 to 1.29, P = 0.002), posterior facial height (WMD: -1.23, 95% CI: -2.08 to -0.38, P = 0.005), convexity angle (WMD: -1.89, 95% CI: -3.12 to -0.66, P = 0.003), and Sella-Nasion plane angle (U1 to SN) (WMD: 3.34, 95% CI: 2.25 to 4.43, P < 0.001) were achieved in the Twin Block appliance. Herbst and Twin Block appliances produced similar effects in the skeletal and dentoalveolar changes including Sella-Nasion-point A (SNA), Sella-Nasion-point B, point A-Nasion-point B (ANB), overjet, and overbite.

CONCLUSION

As the findings revealed both Herbst and Twin Block appliances contributed successfully to the correction of Class II malocclusion. Compared with the Twin Block appliance, the Herbst appliance may have more advantages in mandibular bone movement. Twin Block therapy resulted in more improvement in the aesthetics of the face.

Alveolar Bone and Gingival Changes in Mandibular Anterior Region Following Herbst Appliance Therapy: A Systematic Review and Meta-analysis

Objective

To assess the alveolar bone changes and gingival recession following Herbst appliance therapy.

Materials and methods

Electronic databases such as PubMed, Ovid, Cochrane Library, Lilacs, Scopus, Web of Science, and Embase were searched until August 2022. Hand-searching of major orthodontic journals was performed to identify all peer-reviewed articles potentially relevant to the review. The quality of the selected studies was ranked using the revised Cochrane risk of bias tool for nonrandomized trials-Risk of Bias In Nonrandomized Studies (ROBINS) 1.

Results

Five relevant articles (all nonrandomized studies) were considered for qualitative analysis. The risk of bias was low for four studies and moderate for one. The reduction in the vertical alveolar bone height was 0.13 ± 0.07 mm, with the Herbst appliance. The mean difference in the loss of buccal cortical thickness between the Herbst appliance and untreated control group was 0.22 mm [95% confidence interval (CI) of -0.62-0.18]. Subsequent to Herbst appliance therapy, in the mandibular anterior region 0.1 ± 0.5 mm of gingival recession was observed.

Conclusion

Herbst appliance treatment produces a negligible reduction in the buccal cortical thickness, vertical alveolar bone height, and gingival recession.

Clinical significance

Though the changes produced by the Herbst appliance were minimal, they are clinically important considering the young age of the patients warranting periodic periodontal assessment.

How to cite this article

Kumar MV, Kannan A, Kailasam V. Alveolar Bone and Gingival Changes in Mandibular Anterior Region Following Herbst Appliance Therapy: A Systematic Review and Meta-analysis. Int J Clin Pediatr Dent 2024;17(1):114-120.

Abaloparatide and teriparatide enhance mandibular growth in adolescent rats with site-specific and mechano-related effects

OBJECTIVE

Teriparatide (TPTD) and abaloparatide (ABL) are two osteoanabolic drugs targeting parathyroid hormone (PTH)1R signalling. This study aimed to investigate the effects of TPTD and ABL on the adolescent mandibular growth.

METHOD

In total, 70 4-week-old male Sprague-Dawley rats were randomly divided into 14 groups, treated with intermittent TPDT or ABL at various doses, accompanied by mandibular advancement (MA) or not. 3D printing was used to fabricate an innovative splint for MA. After a 4-week treatment, morphological measurement, histological and immunohistochemical analysis were performed. Mandibular condylar chondrocytes (MCCs) were treated with TPTD or ABL, followed by CCK-8 assay, alcian blue staining, real time-PCR and immunofluorescent staining.

RESULT

In vivo, TPTD or ABL alone increased the condylar length and cartilage thickness, with up-regulated SOX9 and COL II, whilst down-regulated COL X; however, when combined with MA, the promotive effects were attenuated. TPTD or ABL alone increased the mandibular body height and mandibular angle width, whilst increased the mandibular body length and alveolar bone width when combined with MA. In vitro, TPTD or ABL enhanced the MCC proliferation, glycosaminoglycan synthesis, COL II and SOX9 expression, whilst down-regulated COL X, Ihh and PTH1R expression.

CONCLUSION

Both ABL and TPTD enhance mandibular growth in adolescent rats with site-specific and mechano-related effects, including propelling chondrogenesis at the condylar cartilage and promoting bone apposition at other mechano-responsive sites. They behave as promising drugs for mandibular growth modification, and in general ABL seems more potent than TPTD in this context.

Therapeutic approach in Class I malocclusion with impacted maxillary canines

Objective:

To emphasize the importance of diagnosis and discuss the therapeutic approaches that can be used in the orthodontic treatment of Class I malocclusion associated with two impacted maxillary canines. The opening of spaces for traction of these teeth by means of rapid maxillary expansion or extraction of maxillary premolars was contraindicated in the case reported. Therefore, it was decided to open spaces with projection of incisors.

Results:

The obtained results were satisfactory, as a good occlusion was obtained, with adequate functional guides, as well as an improvement in the facial appearance.

Conclusion:

The projection of the incisors prior to traction of the impacted maxillary canines proved to be a valid option in the case described. Ten years after completion of treatment, the case is stable, maintaining periodontal health.

Mandibular incisor inclination and gingival recession after treatment with the Jasper Jumper: a 10-year follow-up

OBJECTIVE

To evaluate the long-term outcomes of Class II treatment with the Jasper Jumper appliance and comprehensive orthodontic treatment concerning inclination of the mandibular incisors and gingival recession.

METHODS

Sixteen patients with Class II malocclusion at a mean age of 12.54y (SD = 1.17) were treated with the Jasper Jumper appliance and comprehensive orthodontic treatment. The mean treatment time was 2.05y (SD = 0.21). Dental records were taken before (T1), after treatment (T2) and 11.90y (SD = 0.48) after debonding (T3). The frequency of gingival recession, clinical crown height and mandibular incisor position were evaluated using intraoral photographs, digital models and lateral cephalograms. Interphase changes were evaluated using dependent t and McNemar's tests. Correlation between clinical crown height and final position of the mandibular incisors was evaluated using Pearson correlation test (P < 0.05).

RESULTS

The frequency of gingival recessions increased over time and was observed in 6 (9.4%), 12 (18.8%) and 24 (37.5%) of the mandibular incisors at T1, T2 and T3, respectively. A significant increase in labial inclination and protrusion of the mandibular incisors was observed between T1 and T2 interval. The clinical crown height significantly increased in the follow-up period (T3-T2) and in the complete observation time (T3-T1). There was no correlation between the amount of labial inclination and protrusion of the mandibular incisors and clinical crown height for all time intervals.

CONCLUSION

No significant correlation between the amount of labial movement of the mandibular incisor and clinical crown height increase was found.

Herbst-multibracket appliance treatment: is there an association between lower incisor position changes and the development of labial gingival recessions?

PURPOSE

To assess a potential association between lower incisor (LI) position changes during Herbst-multibracket appliance (Herbst-MBA) treatment and the development of labial gingival recessions (LGR).

METHODS

All class II patients (Department of Orthodontics, University of Giessen, Giessen, Germany) who had undergone Herbst-MBA treatment until 2015 with study models and lateral cephalograms available from before (T0) and after treatment plus ≥24 months of retention (T3) were included (n = 259). Lateral cephalograms were evaluated regarding LI position changes: iiL/ML (angle between LI long axis and mandibular plane [MP]), ii-MLPg (distance between LI incisal edge and a line perpendicular to MP through pogonion), apex-MLPg (distance between LI apex and a line perpendicular to MP through pogonion), ii-MLii (distance between LI incisal edge and MP on a line perpendicular to MP through incisal edge). Using study models the distance between the cementoenamel junction and the deepest point of the gingival margin was defined as LGR.

RESULTS

The following cephalometric mean changes were recorded (T0-T3): iiL/ML +5.9 ± 5.76° (p = 0.929), ii-MLPg -0.2 ± 0.25 mm (p = 0.430), apex-MLPg +0.1 ± 0.32 mm (p = 0.363), ii-MLii +0.1 ± 0.36 mm (p = 0.206). The mean increase of LGR magnitude measured on the study models was 0.1 ± 0.35 mm. However, no association with the cephalometric LI position changes was found (|R| ≤ 0.2).

CONCLUSION

There is no association between the amount of LI position changes and the development of LGR during Herbst-MBA treatment plus retention. Nevertheless, individual predisposition or excessive treatment changes and extraordinary treatment approaches, respectively, might still lead to development of LGR.

Skeletal and dentoalveolar contributions during Class II correction with Forsus™ FRD appliances : Quantitative evaluation

PURPOSE

Primary objective of the study is to quantify and evaluate the skeletal and dental contributions during sagittal Class II correction with the Forsus™ fatigue resistant device (FRD; 3M Unitek Corp., Monrovia, CA, USA). Secondary objective is to evaluate the overall vertical, soft tissue and chin-throat relation changes with the Forsus™ appliance.

PATIENTS AND METHODS

A retrospective sample of 27 Class II patients treated with the Forsus™ FRD appliance was compared to 20 untreated control subjects who were matched according to age and craniofacial morphology. Pre-Forsus™ (T0) and Post-Forsus™ (T1) cephalograms were subjected to composite cephalometric analysis. Growth changes were subtracted from the treatment changes to obtain the treatment effects of the appliance. The data were analyzed using Student's t‑test and independent t test.

RESULTS

Significant differences were found between the treated and the control group in 16 of 29 measured variables. The overjet and molar relation improved by 4.23 mm and 4.49 mm, respectively. This was mainly achieved by backward movement of maxillary incisors (1.4 mm) and molars (1.22 mm) and forward movement of mandibular incisors (2.26 mm) and molars (2.70 mm). Overbite decreased by 2.24 mm with no changes in mandibular and nasal plane angles.

CONCLUSION

The Forsus™ FRD was effective in correcting Class II malocclusion mainly at the dentoalveolar level. The net skeletal and dentoalveolar contributions towards both overjet and molar correction was 13% and 87%, respectively. The improvement in soft tissue profile and chin-throat configuration was statistically insignificant.

Effects of maxillary incisor inclination on dentoalveolar changes in class II division 1 and 2 non-extraction treatment for Caucasian children - A retrospective study using CBCT

OBJECTIVE

The objective of this study was to investigate the effects of maxillary central incisor (U1) inclination changes on alveolar bone and root length in the 20 Class II division 1 and 20 Class II division 2 (CII div1, CII div2) Caucasian adolescents treated without extraction.

MATERIAL AND METHODS

Forty U1s from each group were assessed for root length and alveolar variables at the crestal, mid-root, and apical levels using sagittal sections obtained from CBCT images pre- and post-treatment. Mixed MANOVAs, Repeated measures MANOVAs, Pearson correlations, and regression analyses were performed.

RESULTS

The facial bone height did not change significantly after an average of 15 degrees of proclination in the CII div2 group, whereas a statistically significant decrease in the palatal bone height was noted. However, in the CII div1 group, a statistically significant reduction in the facial and palatal bone height was observed with mild crown retroclination. Both groups had a significant decrease in total bone thickness at all levels, more decrease in the CII div2 group after treatment. No statistically significant difference in root length was observed between the groups during treatment.

CONCLUSIONS

The findings support that the flaring of retroclined U1s as a process for normalizing U1 inclination did not harm the facial alveolar bone height in the CII div2 non-extraction treatment. Crown proclination itself was not correlated to the amount of root resorption in Class II div1&2 non-extraction treatments in adolescents.

Evaluation of Root Resorption, Tooth Inclination and Changes in Supporting Bone in Class II Malocclusion Patients Treated with Forsus Appliance

OBJECTIVE

The aim of our study was to evaluate apical root resorption and changes in tooth inclinations, marginal bone height, and labio-lingual bone thickness at the mid-root and apical level in mandibular anterior teeth during the Forsus treatment using cone beam computed tomography (CBCT).

METHODS

CBCT scans of 16 subjects (8 males and 8 females) with Class II malocclusion (age group: 13-29 years) taken before and 6 months after the Forsus treatment were evaluated for apical root resorption, tooth inclination, marginal bone height, and thickness of bone at the mid-root and apical level in mandibular anterior teeth.

RESULTS

There was statistically significant root resorption of central incisors (0.39 mm) and canines (0.66 mm); a decrease in the angle of inclination for all teeth; an increase in the marginal bone measurement in labial (1.31 mm) and decrease in lingual (0.93 mm) aspect at the canine region; and an increase in bone width by 0.87 mm and 0.75 mm in central and lateral incisor regions, respectively, at the mid-root level lingually. At the apex level in the canine region, bone width increased by 1.4 mm labially, while it decreased by 2.18 mm lingually; it increased significantly for incisors in the lingual region.

CONCLUSION

The Forsus appliance therapy causes clinically insignificant root resorption and bone changes, and clinically significant proclination of mandibular anterior teeth. The findings of the present study aid clinicians in proper case selection and reinforce the prevention of incisor proclination while using the Forsus therapy to achieve better treatment results and stability.

Class II:2 malocclusion-prevalence and progression of labial gingival recessions during Herbst-Multibracket appliance treatment

OBJECTIVES

To determine the prevalence, incidence, and changes in magnitude of labial gingival recessions (LGR) in class II:2 patients during Herbst-Multibracket appliance (Herbst-MBA) treatment (Tx) plus retention.

SUBJECTS AND METHODS

All class II:2 patients of the Department of Orthodontics, University of Giessen, Germany who completed Herbst-MBA Tx (mean pre-Tx age 15.6 years). The cohort had undergone a Herbst phase (mean 8.1 months) as well as a subsequent MBA phase (mean 14.4 months). Study casts were evaluated from pre-Tx and after Herbst-MBA Tx plus ≥ 24 months of retention.

RESULTS

Ratable pre-Tx and post-retention study casts (total observation period 53.5 ± 10.3 months) were available from 94 out of 173 patients. No significant difference existed regarding pre-Tx LGR data between patients with and without complete records. The prevalence for teeth with LGR ≥ 0.5 mm was 1.4% pre-Tx respectively 6.7% post-retention. The highest values of up to 5.3% (pre-Tx) and 20.2% (post-retention) were determined for the upper first premolars and lower central incisors. Incidence values of 4.7% (all teeth) and up to 14.9% (upper first right premolars) respectively 11.1% (lower central incisors) were calculated (LGR ≥ 0.5 mm). The overall LGR mean magnitudes were 0.01 mm pre-Tx respectively 0.06 mm post-retention.

CONCLUSIONS

For the prevalence of LGR ≥ 0.5 mm an average increase of 5.3% was determined during ≈ 4.5 years of Herbst-MBA Tx plus retention. The highest incidence was seen for lower central incisors and upper right premolars (11.1/14.9%). The overall LGR mean magnitude increased by 0.05 mm.

CLINICAL RELEVANCE

Herbst-MBA Tx is a common approach for class II:2 malocclusions. Very little, however, is known regarding LGR development in respective patients.

Prevalence, magnitude, and incidence of labial gingival recession with Herbst-multibracket appliance treatment: A retrospective cohort study

OBJECTIVE

To assess the prevalence and magnitude of labial gingival recession (LGR) before and after as well as the incidence during Class II:1 Herbst-Multibracket appliance (Herbst-MBA) treatment (Tx) plus retention in a retrospective cohort study.

MATERIALS AND METHODS

Records of Class II:1 patients who completed Herbst-MBA Tx (mean pre-Tx age 14.4 years) at Department of Orthodontics, University of Giessen, Giessen, Germany were analyzed. Tx consisted of a Herbst phase (mean 8.1 months) and a subsequent MBA phase (mean 16.1 months). Study casts from before and after Herbst-MBA Tx plus ≥24 months of retention were evaluated.

RESULTS

A total of 460 pre-Tx and 222 postretention study casts were available (total observation period: 59.2 ± 14.8 months). The overall prevalence for teeth with LGR ≥0.5 mm was 1.1% pre-Tx and 5.3% postretention. The highest prevalence of up to 5.3% (pre-Tx) and 16.4% (postretention) were seen for the lower incisors. Overall, the median magnitude of LGR was 0.0 mm pre-Tx/postretention (mean: 0.05 mm/0.08 mm). Incidence values of 4.0% (all teeth) and 10.0% to 11.4% (lower central incisors) were calculated for LGR ≥0.5 mm.

CONCLUSIONS

The prevalence of LGR ≥0.5 mm increased from, on average, 1.1% to 5.3% during ≈6 years of Herbst-MBA Tx plus retention. The highest incidence was seen in lower incisors (10.0%-11.4%). However, because of the overall mean magnitude of 0.08 mm postretention, the clinical relevance can be considered as insignificant.

Dentoalveolar Evaluation of Lower Incisors by CBCT after Treatment with Herbst Appliance

Abstract This study aimed to evaluate the effects of the Herbst appliance on the proclination and protrusion of the lower incisors, and to verify if the device causes alveolar bone loss in the anterior region of the mandible. This is a retrospective study. The sample consisted of 35 individuals. The treatment group consisted of 22 individuals (8 girls and 14 boys; initial mean age of 8.2 years) who used the Cantilever Herbst appliance for a period of 12 months. The control group consisted of 13 individuals (3 girls and 10 boys; initial mean age of 8.9 years) who received no treatment and were followed up for a period of approximately 18 months. Cone-beam computed tomography scans were performed at the beginning and at the end of the observational period. The medullary bone thickness (MT), buccal cortical bone thickness (BCT), lingual cortical bone thickness (LCT), and lower incisors proclination and protrusion were evaluated. Data were submitted to statistical analysis (ANCOVA and Student’s t-test) with a significance level of 5%. There was no significant difference in MT, BCT, LCT and incisor proclination between groups. Incisor proclination increased in the treated group with no statistical significance. The treatment group showed a significant increase in the protrusion of the incisors (p = 0.02). The Herbst appliance promoted a small proclination and protrusion of the lower incisors, without relevant clinical implications. The Herbst appliance did not cause bone loss in the anterior region of the mandible during Class II treatment.

Long-term effects of Class II orthodontic treatment on oral health

AIM

To investigate the long-term (≥15 years) benefit of orthodontic Class II treatment (Tx) on oral health (OH).

SUBJECTS AND METHODS

All patients (Department of Orthodontics, University of Giessen, Giessen, Germany) who underwent Class II correction (Herbst-multibracket Tx, end of active Tx ≥ 15 years ago) and agreed to participate in a recall (clinical examination, interview, impressions, and photographs) were included. Records after active Tx were used to assess the long-term OH effects. Data were compared to corresponding population-representative age-cohorts as well as to untreated Class I controls without orthodontic Tx need during adolescence.

RESULTS

Of 152 treated Class II patients, 75 could be located and agreed to participate at 33.7 ± 3.0 years of age (pre-Tx age: 14.0 ± 2.7 years). The majority (70.8%) were fully satisfied with their teeth and with their masticatory system. The Decayed, Missing, Filled Teeth Index (DMFT) was 7.1 ± 4.8 and, thus, almost identical to that of the untreated Class I controls (7.9 ± 3.6). In contrast, the DMFT in the population-representative age-cohort was 56% higher. The determined mean Community Periodontal Index (CPI) maximum score (1.6 ± 0.6) was also comparable to the untreated Class I controls (1.7 ± 0.9) but in the corresponding population-representative age-cohort it was 19-44% higher. The extent of lower incisor gingival recessions did not differ significantly between the treated Class II participants and the untreated Class I controls (0.1 ± 0.2 vs. 0.0 ± 0.1 mm).

CONCLUSION

Patients with orthodontically treated severe Class II malocclusions had a lower risk for oral health impairment than the general population. The risk corresponded to that of untreated Class I controls (without orthodontic Tx need during adolescence).

Displacement of the Mandibular Condyles Immediately after Herbst Appliance Insertion - 3D Assessment

OBJECTIVE

To test the following two hypotheses regarding the consequences of Herbst appliance (HA) insertion: 1) a significant clockwise mandibular rotation will occur and 2) the displacement of the condyles will follow the same magnitude of the changes of overjet (OJ) and overbite (OB).

METHODS

Virtual 3D surface models of 25 patients were generated from cone-beam computed tomographs taken before treatment and immediately after HA insertion. Scans were registered on the cranial base and were analyzed using point-to-point measurements, color-coded maps, and semitransparent overlays. Statistical tests included correlation and simple regression analysis.

RESULTS

Pitch rotation, ranging from -2.2° to 2.2° (mean, 0.2°), was observed in clockwise and counterclockwise directions. Condylar sagittal displacement presented a positive correlation with OJ changes. Each millimeter of OJ correction resulted in an anterior condylar displacement of approximately 0.95 mm. Vertical condylar displacement correlated with OB changes and varied mostly between 2 mm and 4.5 mm.

CONCLUSION

Immediately after HA insertion, no significant clockwise mandibular rotation was observed. The condyles were displaced anteriorly and inferiorly. Condylar anterior displacement and OJ correction presented a ratio close to 1:1. The vertical displacement of the condyles did not follow the same magnitude of OB changes.