Post-orthodontic lower incisor inclination and gingival recession-a systematic review

A novel approach for gingiva thickness measurements around lower anterior teeth by means of dental magnetic resonance imaging

OBJECTIVE

This diagnostic accuracy study aims to present the first measurements of gingiva thickness around lower anterior teeth using dental magnetic resonance imaging (MRI) and to compare these measurements with two established methods: (1) gingival phenotype assessment via periodontal probing, and (2) the superimposition of cone-beam computed tomography (CBCT) scans with intraoral scans of teeth and gums.

MATERIALS AND METHODS

Ten patients with substantial orthodontic treatment need and anterior mandibular crowding were consecutively included in this clinical case series. After periodontal probing, each patient underwent a CBCT scan, an intraoral scan of the mandible, and an MRI investigation using a novel mandibula 15-channel dental coil.

RESULTS

The mean gingiva thickness was 0.72 mm measured on MRI and 0.97 mm measured on CBCT, with a mean difference between the measurement methods of 0.17 ± 0.27 mm (p < 0.001). Measurement agreement between the index tests (MRI and CBCT) and the clinical reference standard (probing) yielded an overall percent agreement of 64.94% and 47.02% for MRI and CBCT, respectively. Teeth with thin phenotypes were associated with lower soft tissue dimensions in both free (MRI: 0.56 mm vs. CBCT: 0.79 mm) and supracrestal gingiva (MRI: 0.75 mm vs. CBCT: 1.03 mm) when compared to those with thick phenotypes. However, only the measurements obtained from MRI scans showed statistically significant differences between the two phenotypes.

CONCLUSION

Dental MRI successfully visualizes delicate structures like the gingiva in the anterior mandible and achieves a high correlation with superimposed CBCT scans, with clinically acceptable deviations.

CLINICAL RELEVANCE

The present study helps to establish dental MRI as a radiation-free alternative to conventional radiographic methods.

Lower incisor inclination and thickness of the alveolar process and mandibular symphysis in the development of gingival recession: A retrospective cohort study

Introduction

Retrospective studies have found conflicting results regarding the relationship between lower incisor inclination and the development of gingival recession (GR) after orthodontic treatment.

Objective

This study aimed to investigate the relationship between lower incisor inclination and alveolar process (AP) and mandibular symphysis (MS) thickness in the development of GR.

Materials and Methods

Frontal intraoral photography and cephalometric radiography were conducted before (T0) and after (T1) orthodontic treatment of 62 subjects. The presence of GR was considered when the cementoenamel junction was visible in the lower incisor on the frontal intraoral photograph. The circumstances for improvement, stability, and worsening of the gingival situation were based on the reduction, maintenance, and increase in the number of lower incisors with GR before and after treatment. To measure the incisor-mandibular plane angle (IMPA) and the thickness of the AP and the MS were used the cephalometric radiographs.

Results

Men had a significantly thicker MS than women at T0 and T1 (p < 0.0004). There was a significant reduction of approximately 10% in AP between T0 and T1 (p < 0.0001). Among subjects without GR at T0, 70.4% presented a stable gingival situation at T1. For subjects with 1 lower incisor with GR at T0, 50% showed improvement in the gingival situation at T1, 21.4% remained stable, and 28.6% experienced worsening. Sixteen lateral incisors presented a worsening gingival situation, representing an increase of 129% compared to the central incisors.

Conclusion

No relationship was found between lower incisor inclination and the thickness of the AP and MS in the development of GR.

Spontaneous Recession Repair after Orthodontic Treatment: Case Report with the Use of Digital Approach for Quantification of Soft Tissue Changes

The article presents a case of spontaneous recession repair in a male patient with Class II malocclusion, division 1, after orthodontic treatment with aligners. The difference in digital recession depth was measured before and at the end of treatment by means of automatic intraoral scans superimposition within adapted software while using "Cross section" and "Measuring" instruments. Digital analysis of intraoral scans obtained before and at the end of treatment has revealed that recessions within the area of teeth 1.5, 1.4, 1.3, 1.2, 1.1, 2.1, 2.2, 2.3, 2.4, and 2.5 have improved, and recession depth reduced by 0.73 ± 0.08 mm, 1.02 ± 0.09 mm, 1.86 ± 0.13 mm, 0.72 ± 0.09 mm, 0.73 ± 0.04 mm, 0.67 ± 0.06 mm, 0.66 ± 0.07 mm, 1.50 ± 0.12 mm, 1.10 ± 0.05 mm, and 0.45 ± 0.04 mm, appropriately. The present case report emphasizes that orthodontic correction of altered tooth position (angulation, inclination, and rotation) under certain clinical conditions may be considered as an effective method for soft tissue contour optimization in cases when pre-treatment tooth position could be interpreted as a causative factor or associated with diagnosed recession. The following outcomes could be related, but not limited to creeping attachment mechanism, bone-housing centering effects, optimization of occlusal load distribution with ruling out peak zones of strain accumulation, and mucogingival stress leveling. Due to the authors' knowledge, the present case report is the first one where the signs of spontaneous recession repair after orthodontic treatment were evidenced with the intraoral scans and quantified by the specifically implemented digital analysis approach.

Accurate gingival recession quantification using 3D digital dental models

Objectives

To develop and validate a method for accurate quantitative assessment of gingival recessions based on superimposition of serial 3D digital models.

Materials and methods

Gingival recessions of mild (0.5–2 mm) and increased (3–7 mm) severity were simulated on stone casts and surface models were created. The outlines of the gingival margins of the mild (A) and severe recessions (B) were compared to the original gingival margins following 3D best fit superimposition through a gold standard technique (GS), which used intact adjacent structures, and the tested method (CC), which used single tooth crowns at the position of recessions, as superimposition reference. The primary outcome was the distance between the most apical point of each corresponding gingival margin along the respective tooth long axis.

Results

For mild recessions, the median difference of the test methods (CC_A) from the reference method (GS_A) was 0.008 mm (IQR: 0.093; range: − 0.143, 0.147). For severe recessions, the median difference of the test method (CC_B) from the reference method (GS_B) was 0.009 mm (IQR: 0.091; range: − 0.170, 0.198). The proposed method (CC) showed very high intra- and inter-operator reproducibility (median: 0.025 and 0.033 mm, respectively).

Conclusions

The suggested method offers highly accurate monitoring of gingival margin changes and diagnosis of gingival recessions using 3D digital dental models. The method is applicable irrespective of changes in tooth position or form, allowing for assessments over any time span.

Clinical relevance

The accurate detection and visualization of gingival margin changes in 3D will enhance diagnosis and patient-doctor communication.

Multi-disciplinary treatment of maxillofacial skeletal deformities by orthognathic surgery combined with periodontal phenotype modification: A case report

BACKGROUND

Maxillofacial deformities are skeletal discrepancies that cause occlusal, functional, and esthetic problems, and are managed by multi-disciplinary treatment, including careful orthodontic, surgical, and periodontal evaluations. However, thin periodontal phenotype is often overlooked although it affects the therapeutic outcome. Gingival augmentation and periodontal accelerated osteogenic orthodontics (PAOO) can effectively modify the periodontal phenotype and improve treatment outcome. We describe the multi-disciplinary approaches used to manage a case of skeletal Class III malocclusion and facial asymmetry, with thin periodontal phenotype limiting the correction of deformity.

CASE SUMMARY

A patient with facial asymmetry and weakness in chewing had been treated with orthodontic camouflage, but the treatment outcome was not satisfactory. After examination, gingiva augmentation and PAOO were performed to increase the volume of both the gingiva and the alveolar bone to allow further tooth movement. After orthodontic decompensation, double-jaw surgery was performed to reposition the maxilla-mandibular complex. Finally, implant placement and chin molding were performed to restore the dentition and to improve the skeletal profile. The appearance and function were significantly improved, and the periodontal tissue remained healthy and stable.

CONCLUSION

In patients with dentofacial deformities and a thin periodontal phenotype, multi-disciplinary treatment that includes PAOO could be effective, and could improve both the quality and safety of orthodontic-orthognathic therapy.

Does Early Treatment Improve Clinical Outcome of Class II Patients? A Retrospective Study

The present study was carried out to evaluate the benefits from one-phase Class II Early Treatment (ET) using extraoral forces and functional appliances but without intermaxillary forces and eventual lower leeway space preservation compared to two-phase Class II Late Treatment (LT) with the need for extractions and full fixed appliances as well as lower incisor proclination. The ET group (n = 239, 115 M, 124 F, mean age 10.6 ± 1.2 years), with first premolars not in contact and the second deciduous lower molars preserved, was compared to the LT group (n = 288, 137 M, 151 F, mean age 12.4 ± 1.5 years). The ET group was first treated with headgears, growth guide appliances, or Teuscher activators and, in borderline crowding cases, with lower space maintenance by a lingual arch, lip bumper, or fixed utility arch. The LT group and the second phase of ET were treated with full fixed appliances including intermaxillary forces such as Class II elastics or noncompliance devices; headgear and a growth guide appliance were also used. Cephalograms and plaster models were taken before (T1) and after treatment (T2) to calculate cephalometric changes and space balance discrepancies. The differences between T1 and T2 were analyzed by a t-test for normally distributed data and by the Mann-Whitney Test for nonnormally distributed data at a level of p < 0.05. The groups were defined as statistically homogeneous at T1. A statistical analysis showed that the ET group (mean treatment time 35.3 ± 13.3 months) was significantly associated with a 22.2% lower extraction rate, 15.9% less need for a full fixed appliance, and more than 5° less incisor proclination in the nonextraction cases compared to the LT group (mean treatment time 25.9 ± 8.1 months); treatment time significantly increased in the ET group compared to the LT group. Early Class II treatment resulted in a significant treatment effort reduction in more than one third of the patients and less lower incisor proclination, even if it clinically increased treatment time.

Gingival Recessions and Periodontal Status after Minimum 2-Year-Retention Post-Non-Extraction Orthodontic Treatment

The objectives of this study were to assess gingival recessions (GR) and periodontal status in patients previously treated with non-extraction orthodontic treatment and retention at a follow-up of a minimum of two years after the end of treatment. Data from patients aged between 16 and 35 years with a previous non-extraction orthodontic treatment and at least 2 years of retention and full records before and after treatment were collected. The casts were digitalized using the 3Shape TRIOS® intraoral scanner and the Viewbox4 software was used for the measurements. The following parameters were scored: inclination of the lower and upper incisors (IMPA and I^SN) and anterior crowding (Little index). The included patients were recalled for a clinical periodontal follow-up examination and the following parameters were evaluated: buccal and lingual GR (mm) of incisors and canines, bleeding of probing score, plaque score, and gingival phenotype. The digital cast analysis showed a mean Little index of 7.78 (SD 5.83) and 1.39 (SD 0.79), respectively, before and after treatment. The initial and final cephalometric analyses showed an I^SN of 103.53° and 105.78°(SD 7.21) and IMPA of 91.3°and 95.1°, respectively. At the follow-up periodontal visits, the patients showed an overall low oral hygiene with bleeding at probing in 66.6% and plaque in the anterior area in 76.2% of patients. From the total examined 240 teeth of the frontal sextants, three patients had GR (from 1 to 6.5 mm): in the upper arch two at canines and one at central incisor, whereas in the lower arch two at central and one at lateral incisors. The gingival phenotype was thick in 55% of cases. The lingual-to-lingual retainers at follow-up were present in 61.9% of patients. A slight increased risk for buccal GR development was found only in correlation with the presence of fixed retainer and thin gingival phenotype mainly in patients with gingivitis. Thus, non-extraction orthodontic treatment performed with controlled forces and biomechanics seems to not affect the development of GR or the periodontal health after retention.

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.

Long-term effect on adenoid dimensions and craniocervical angulation after maxillary expansion with fixed or functional appliances

Background

Maxillary expansion is a common orthodontic procedure that could have a positive effect also on airway patency. The aim of the present study was to evaluate the long-term effects of rapid maxillary expansion (RME) on nasopharyngeal area and cranio-cervical angulation in growing patients, compared to controls treated with a function-generating bite appliance (FGB).

Material and Methods

Sixty patients aged 6-14 consecutively treated with RME or FGB were selected retrospectively and divided into two groups. Lateral cephalograms taken before and after treatment were retrieved, and the nasopharyngeal area, delimited superiorly by a sella-posterior nasal spine (PNS) line and inferiorly by a basion-PNS line, and the cranio-cervical angulation were measured.

Results

The mean observation time was 17.6 ± 8 months. No differences were present between the two groups regarding age and gender. The nasopharyngeal area increased significantly in both groups after treatment, but with no statistically significant difference between them. The cranio-cervical angulation showed no differences within or between groups.

Conclusions

Maxillary deficiency treatment with either RME or FGB was followed by a comparable increase in nasopharyngeal area.

Key words:Rapid maxillary expansion, Airway, Nasopharyngeal area, Adenoid.

Association of hard and soft tissue factors with gingival recession in orthodontically treated patients: A retrospective study

INTRODUCTION

Orthodontic treatment is thought as a contributory factor in the development of recession. The objective of this study was to determine the factors associated with a gingival recession in patients who underwent orthodontic mechano-therapy.

MATERIAL AND METHODS

A retrospective chart review of 72 post-orthodontic cases done at the dental clinics of Aga Khan University hospital that were treated from 2009 to 2017. After evaluating dental records patients were recruited based on inclusion and exclusion criteria. Patients were divided into two groups based on the presence or absence of gingival recession on posttreatment photographs. Patients in each group were further assessed on the following factors: (1) Lower incisor inclination (IMPA). (2) Tissue thickness on the facio-lingual dimension. (3) Alveolar bone height. (4) Alveolar bone thickness.

RESULTS

The mean age of patients at the start of treatment was 16.56±5.66years. Gingival recession was found in 40.3% of our patients while 59.7% of patients had no recession found after orthodontic treatment. Univariable logistic regression was applied for factors associated with a gingival recession following orthodontic treatment which showed that the odds ratio of gingival recession in thin gingival biotype are 14.4 times more than in thick gingival biotype. Multivariable regression analysis showed that the cases had 10.2 times more recession in thin biotype than those in the thick gingival biotype while adjusting for pre- and posttreatment alveolar heights following orthodontic treatment and with a confidence interval [95% CI=2.69 to 38.40].

CONCLUSIONS

It was concluded from this study that 40% of patients developed gingival recession in one or more teeth during orthodontic treatment. Among different factors pre-treatment, gingival biotype of patients and male gender were the factors that were more associated with the development of gingival recession.

Postorthodontic lower incisor and canine inclination and labial gingival recession in adult patients : A prospective study

PURPOSE

The goal was to determine whether changes in the inclination of lower incisors and canines upon orthodontic treatment with fixed appliances poses a threat for labial gingival recession in adult patients.

METHODS

The sample of this prospective clinical trial consisted of 32 adult patients (mean age 25.08 ±6.50 years) treated with fixed appliances. Plaque and bleeding indices, probing pocket depth, clinical attachment level, gingival recession height (GR) and width (GRW), gingival thickness (GT), and keratinized tissue width were clinically recorded, while cone beam computed tomography (CBCT) was used to evaluate teeth inclination before (T1) and after treatment (T2). Oral hygiene, brushing habits, and smoking were controlled.

RESULTS

During orthodontic treatment on 15 (8.33%) teeth (10 incisors and 5 canines), spontaneous complete improvement of pre-existing GR was observed. On 2 incisors, GR decreased and on 3 teeth GR did not change. Moreover, 1 incisor presented an increased GR, while 2 teeth developed new defects. Mean GR, GRW, and GT decreased significantly only on the incisors. Proclination of incisors and canines during treatment (compared with retroclination of the teeth) implicated a lower reduction in GR at T2: 0.19 mm (p = 0.034) and 0.18 mm (p = 0.037), respectively. Multiple regression analysis confirmed that more tooth proclination was associated with a higher risk for an increase in GR (p < 0.00).

CONCLUSION

Properly planned changes in lower incisor and canine inclination can be carried out in adult patients without posing a high risk to labial gingival recessions if the individual periodontal biotype is respected. The reported outcomes underscore the orthodontic principle to keep tooth roots inside the alveolar bone.

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.

Soft-tissue changes after Class II malocclusion treatment using the Sander bite-jumping appliance: a retrospective study

BACKGROUND

The soft tissue profile outcome after functional treatment of Class II malocclusion is important for a patient's aesthetic and psychosocial results. The soft tissue effects of the Sander bite-jumping appliance (BJA), which is the device that produces the greatest mandibular advancement according to a systematic review, have never been investigated. The aim of the present study was to assess the soft tissue effects of the BJA in comparison to matched untreated controls.

METHODS

A total of 19 patients treated with BJA during puberty were retrospectively recruited, and 15 untreated controls were retrieved from a previous growth study to match the treated group. Lateral cephalograms were used to evaluate the pre- and post-treatment differences in the ANB angle, the inclination of the upper and lower incisors, facial convexity, the nasolabial angle and the sagittal position of the skeletal and soft tissue at points A and B. Independent t-tests or Mann-Whitney U tests were used to detect differences between the two groups.

RESULTS

Statistically significant differences were found for the ANB angle, the inclination of the upper incisors and facial convexity.

CONCLUSIONS

Functional treatment of Class II patients with the Sander BJA during puberty was effective at improving the profile and reducing the facial convexity angle in the short term.

Do orthodontic patients develop more gingival recession in anterior teeth compared to untreated individuals? A systematic review of controlled studies

OBJECTIVE

To investigate, in an evidence-based manner, the contemporary available information regarding the development of gingival recession in the anterior teeth of orthodontically treated and age-matched untreated individuals.

MATERIAL AND METHODS

Eight databases were searched without restrictions from the date of coverage initiation to June 30th, 2019 (registration in PROSPERO: CRD42018080948). Studies evaluating gingival recession development following comprehensive orthodontic treatment were reviewed. Following study selection, data extraction and risk of bias assessment, the random effects model was employed for exploratory data synthesis. The confidence in the retrieved estimates was appraised using current guidelines.

RESULTS

Finally, three studies, with a follow-up of 6 years maximum, were identified. Overall, the amount of gingival recession did not increase significantly immediately after treatment with normal occlusion. However, for some of the comparisons considered, the risk for orthodontic patients to present with labial gingival recession seemed to increase, especially during retention [mandibular incisors 6 years post-treatment: Odds Ratio: 8.81, 95% Confidence Interval: 1.93-40.07, p=0.005].

CONCLUSION

Although the amount of recession does not differ, some increase in the risk for gingival recession development in the anterior teeth may be encountered in orthodontically-treated individuals compared to untreated subjects with normal occlusion. However, these findings should be viewed cautiously until more studies of high quality become available. Good practice would suggest that it is important to identify patients at potential risk and consider the possible implications for orthodontic treatment.

Which factors influence orthodontists in their decision to extract? A questionnaire survey

Background

To evaluate the relative influence of different criteria in the choice between extraction and nonextraction treatment in current orthodontics, and to assess how the percentage of extractions has evolved over time.

Material and Methods

Pre-treatment records (panoramic radiograph, lateral cephalogram, study casts and photographs) of fourteen cases in permanent dentition (adult or adolescent) with class I molar relationship and moderate anterior crowding were evaluated by 28 orthodontists. For each case, each orthodontist filled out a questionnaire reporting his treatment plan proposal (extraction or nonextraction) and the importance of specific parameters in his decision-making process, using categorical scales. Orthodontists practicing for more than 15 years were also asked to compare this decision with the one they would have taken at the beginning of their professional career.

Results

The two most important factors in the decision-making were the soft tissue profile and the amount of crowding. The least important factor was the presence of third molars. In cases of nonextraction treatment, the lack of space was managed mostly by dental expansion and stripping. Twenty percent of the case evaluations revealed extraction(s) decisions. Among the orthodontists practicing for more than 15 years, the current extraction rate reached 24%, whereas the same orthodontists reported they would have extracted in 39% of the cases in the past.

Conclusions

The present study suggests that soft tissue profile has a higher impact than traditional criteria such as cephalometric measurements in the extraction decision. This is associated with a decreased extractions rate compared to the past.

Key words:Orthodontics, extractions, survey, treatment planning.