Cone-Beam Computed Tomography and Interdisciplinary Dentofacial Therapy: An American Academy of Periodontology Best Evidence Review Focusing on Risk Assessment of the Dentoalveolar Bone Changes Influenced by Tooth Movement

Multivariate analysis of alveolar bone dehiscence and fenestration in anterior teeth after orthodontic treatment: A retrospective study

OBJECTIVE

To compare the prevalence of fenestration and dehiscence between pre- and post-orthodontic treatment and to explore the factors related to fenestration and dehiscence in the anterior teeth after treatment.

METHODS

This study included 1000 cone-beam computed tomography (CBCT) scans of 500 patients before (T1) and after (T2) orthodontic treatment. These images were imported into Dolphin 11.9 software to detect alveolar fenestration and dehiscence in the anterior teeth area. The chi-square test and Fisher's exact test were performed to compare the prevalence of alveolar bone defects between time points T1 and T2. A total of 499 patients were selected for logistic regression analysis to examine the correlation among age, sex, crowding, sagittal facial type, extraction, miniscrew use and fenestration or dehiscence post-treatment.

RESULTS

Except for the maxillary lingual fenestration and labial fenestration of mandibular canines, a significant change in the prevalence of fenestration and dehiscence was noted between time points T1 and T2 (P < .025). Multinomial logistic regression showed that age, miniscrew use and extraction highly influenced the prevalence of anterior lingual dehiscence (P < .05). Dehiscence of the mandibular labial side (skeletal Class III vs. I, OR = 2.368, P = .000) and fenestration of the mandibular lingual side (skeletal Class II vs. I, OR = 2.344, P = .044) were strongly correlated with the sagittal facial type. Dehiscence of the maxillary labial side (moderate vs. mild, OR = 1.468, P = .017) was significantly associated with crowding.

CONCLUSIONS

Older age, maxillary moderate crowding, skeletal Class III, extraction and miniscrew potentially significantly affect the prevalence of anterior teeth dehiscence. Adult females, skeletal Class III patients on the mandibular labial side and skeletal Class II patients on the mandibular lingual side should be monitored for anterior teeth fenestration.

Automatic tooth periodontal ligament segmentation of cone beam computed tomography based on instance segmentation network

Objective

The three-dimensional morphological structures of periodontal ligaments (PDLs) are important data for periodontal, orthodontic, prosthodontic, and implant interventions. This study aimed to employ a deep learning (DL) algorithm to segment the PDL automatically in cone-beam computed tomography (CBCT).

Method

This was a retrospective study. We randomly selected 389 patients and 1734 axial CBCT images from the CBCT database, and designed a fully automatic PDL segmentation computer-aided model based on instance segmentation Mask R-CNN network. The labels of the model training were 'teeth' and 'alveolar bone', and the 'PDL' is defined as the region where the 'teeth' and 'alveolar bone' overlap. The model's segmentation performance was evaluated using CBCT data from eight patients outside the database.

Results

Qualitative evaluation indicates that the PDL segmentation accuracy of incisors, canines, premolars, wisdom teeth, and implants reached 100%. The segmentation accuracy of molars was 96.4%. Quantitative evaluation indicates that the mIoU and mDSC of PDL segmentation were 0.667 ± 0.015 (>0.6) and 0.799 ± 0.015 (>0.7) respectively.

Conclusion

This study analysed a unique approach to AI-driven automatic segmentation of PDLs on CBCT imaging, possibly enabling chair-side measurements of PDLs to facilitate periodontists, orthodontists, prosthodontists, and implantologists in more efficient and accurate diagnosis and treatment planning.

Three-dimensional assessment of periodontal support of lower incisors for skeletal Class II malocclusion undergoing presurgical orthodontic treatment with different vertical skeletal patterns

BACKGROUND

The aim of the present study was to compare periodontal support changes during retraction of mandibular anterior teeth for skeletal Class II malocclusion with different facial divergence and to analyze relevant factors influencing bone remodeling by applying three-dimensional (3D) cone-beam computed tomography (CBCT) reconstruction technology.

METHODS

Forty-eight patients with Class II malocclusion requiring surgical orthodontic treatment enrolled in the study were divided into the hyperdivergent group (n = 16), normodivergent group (n = 16) and hypodivergent group (n = 16) according to their vertical skeletal patterns. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T1) and after presurgical orthodontic treatment (T2). The two-dimensional (2D) alveolar bone morphology, movement of mandibular central incisors and volume of the alveolar bone around incisors were measured on the labial and lingual sides by 3D CBCT reconstruction technology. Statistical analyses were performed with one-way ANOVA, paired t tests and multiple linear regression.

RESULTS

During presurgical orthodontic treatment, the alveolar bone height on the labial side of the hyperdivergent group decreased significantly (P ≤ 0.05), but was maintained in the normodivergent and hypodivergent groups (P > 0.05). However, the alveolar bone volume, alveolar bone thickness at each level and alveolar bone height on the lingual side decreased significantly for all the groups. Apart from the initial morphometric measurements at T1, the morphology of lingual alveolar bone at T2 was significantly influenced by the direction and amount of tooth movement. Horizontal retraction and vertical protrusion of the root apex were negatively related to the alveolar bone on the lingual side after presurgical orthodontic treatment.

CONCLUSION

For Class II malocclusion patients undergoing presurgical orthodontic treatment, the changes in the periodontal support of the lower central incisors varied in different vertical skeletal patterns. There exists a great periodontal risk of alveolar bone resorption on the lingual side for various vertical types. To avoid alveolar bone deterioration, it is essential to investigate the bone remodeling of patients with different alveolar bone conditions and cautiously plan tooth movement prior to orthodontic treatment. Moreover, 3D measurements based on CBCT construction can provide complementary information to traditional 2D measurements.

Thermographic examination of gingival phenotypes: correlation between morphological and thermal parameters

OBJECTIVES

To evaluate the clinical and thermographic aspects of the gingival phenotype (GP) in healthy subjects.

MATERIALS AND METHODS

The study sample examined 264 teeth, upper and lower incisors, comprising 132 central incisors (CI) and 132 lateral incisors (LI), in 33 healthy volunteers. Four periodontal parameters were recorded systematically: ratio of width to length of the dental crown (CW/CL), height of the gingival attachment (KGW), probing depth (PD), and gingival transparency (GT). The temperatures of the attached gingiva (KGW temp) and the free gingival margin (FGM Temp) were also recorded by way of infrared thermography (IRT).

RESULTS

The average age of the sample was 30.70 ± 7.65 years. Of the 264 teeth evaluated, 76.1% had a thin GP. There was a significant association between CW/CL (p < 0.001), KGW (p < 0.001), PD (p < 0.007), and FGM Temp (p < 0.006) with the tooth groups. The results show a significant and inversely proportional correlation between clinical parameters and gingival temperature (p < 0.05). A significant association was found between CW/CL (p < 0.026); KGW (p < 0.001); and GP.

CONCLUSION

CW/CL, KGW, PD, and FGM Temp vary according to tooth group. The majority of the sample presented with the thin GP, which was more prevalent in the lower LIs and CIs. No significant association could be observed between thermographic parameters and GP.

CLINICAL RELEVANCE

Knowledge of the temperature of the gingival tissues can be useful in helping to diagnose and plan periodontal treatments. Moreover, our findings will help future studies evaluate the use of IR as an auxiliary diagnostic method in dentistry, eliminating GP as a confounding factor, since it does not seem to influence the temperature of the gingival tissues.

Treatment alternatives for the rehabilitation of the posterior edentulous maxilla

Rehabilitation of the edentulous maxilla with implant-supported fixed dental prostheses can represent a significant clinical challenge due to limited bone availability and surgical access, among other factors. This review addresses several treatment options to replace missing teeth in posterior maxillary segments, namely the placement of standard implants in conjunction with maxillary sinus floor augmentation, short implants, tilted implants, and distal cantilever extensions. Pertinent technical information and a concise summary of relevant evidence on the reported outcomes of these different therapeutic approaches are presented, along with a set of clinical guidelines to facilitate decision-making processes and optimize the outcomes of therapy.

Errors and complications in clinical periodontal practice due to methodologic bias and bad interpretation of the evidence

Different types of errors and complications may arise during and after the execution of periodontal or implant-related procedures. Some of the most relevant, although also controversial, and less commented, causative agents of errors and complications are methodological biases and bad interpretation of the evidence. Proper assessment of the literature requires of solid clinical knowledge combined with a systematic approach built on the recognition of common methodological biases and the avoidance of interpretive errors to critically retrieve, dissect, and judiciously apply available information for the promotion of periodontal and peri-implant health. This review addresses common types of methodological bias and interpretive errors that can alter the reader's perceptions on the real effect and potential ramifications of the reported outcomes of a given therapeutic approach due to bad interpretation of the available evidence: (1) types of methodological biases; (2) spin and interpretive bias; (3) interpretation pitfalls when assessing the evidence (4) choice of relevant endpoints to answer the question(s) of interest; and (5) balance between statistical significance and clinical relevance.

Complications and treatment errors involving periodontal tissues related to orthodontic therapy

In this review, typical clinical complications involving periodontal tissues are illustrated that can be encountered in conjunction with orthodontic therapy (OT). Special considerations are given for various clinical scenarios, such as the patient presenting in periodontal health, with periodontitis, or with mucogingival conditions. While some of the complications are seen as common side effects of OT, other, more severe, problems that could have been avoided may be viewed as treatment errors. Recommendations are made on how to prevent these complications, based on the currently available evidence, on clinical practice guidelines, and on expert opinion. In conclusion, while there are several areas in which OT can have unwanted adverse effects on periodontal/mucogingival conditions, there is also great potential for synergies, offering opportunities for close cooperation between the two specialties (periodontics and orthodontics) for the benefit of patients affected by tooth malpositioning and/or periodontal or mucogingival problems.

Complications and treatment errors in periodontal and implant therapy

The assortment of periodontal and implant-related treatments has been continuously improved over the last 50 years. Once the decision-making process has been established and the treatment procedure applied, the partial or complete resolution of the problem (eg, periodontal probing depth reduction, clinical attachment level gain, gingival recession reduction, dental hypersensitivity decrease) and a diagnosis change with no or minimal occurrence of adverse events (ie, complications, harms, technical errors, or adverse/side effects) can be expected. The clear identification of the potential types of adverse effects, complications, or even errors is important for contemporary decision-making processes, as they may be related to different local, systemic, and technical aspects. This chapter focused on four core components: (a) providing periodontal definitions for errors, complications, harms, and side effects; (b) defining the types of risk and the clinical impact of adverse effects, errors, and complications in periodontal and peri-implant therapies; (c) evaluating the influence of accidental errors versus the lack of a proper treatment planning; and (d) reporting on the importance of establishing the "net benefit ratio" between the clinical improvements promoted by the therapy and the occurrence of potential adverse events.

Accurate gingival segmentation from 3D images with artificial intelligence: an animal pilot study

BACKGROUND

Gingival phenotype plays an important role in dental diagnosis and treatment planning. Traditionally, determining the gingival phenotype is done by manual probing of the gingival soft tissues, an invasive and time-consuming procedure. This study aims to evaluate the feasibility and accuracy of an alternatively novel, non-invasive technology based on the precise 3-dimension (3D) soft tissue reconstruction from intraoral scanning and cone beam computed tomography (CBCT) to predict the gingival biotype.

METHODS

As a proof-of-concept, Yorkshire pig mandibles were scanned, and the CBCT data were fed into a deep-learning model to reconstruct the teeth and surrounding bone structure in 3D. By overlaying the CBCT scan with the intraoral scans, an accurate superposition was created and used for virtual measurements of the soft tissue thickness. Meanwhile, gingival thicknesses were also measured by a periodontal probe and digital caliper on the buccal and lingual sides at 3 mm apical to the gingival margin of the posterior teeth and compared with the virtual assessment at the same location. The data obtained from virtual and clinical measurements were compared by Wilcoxon matched-pairs signed-rank analysis, while their correlation was determined by Pearson's r value. The Mann-Whitney U test was used for intergroup comparisons of the amount of difference.

RESULTS

Among 108 investigated locations, the clinical and virtual measurements are strongly positively correlated (r = 0.9656, P < 0.0001), and only clinically insignificant differences (0.066 ± 0.223 mm) were observed between the two assessments. There is no difference in the agreement between the virtual and clinical measurements on sexually matured samples (0.087 ± 0.240 mm) and pre-pubertal samples (0.033 ± 0.195 mm). Noticeably, there is a greater agreement between the virtual and clinical measurements at the buccal sites (0.019 ± 0.233 mm) than at the lingual sites (0.116 ± 0.215 mm).

CONCLUSION

In summary, the artificial intelligence-based virtual measurement proposed in this work provides an innovative technique potentially for accurately measuring soft tissue thickness using clinical routine 3D imaging systems, which will aid clinicians in generating a more comprehensive diagnosis with less invasive procedures and, in turn, optimize the treatment plans with more predictable outcomes.

Evaluation of alveolar bone morphology of incisors with different sagittal skeletal facial types by cone beam computed tomography: A retrospective study

Background

Safe orthodontic tooth movement should be performed within the alveolar bone. The purpose of this study was to evaluate the morphology of the alveolar bone of incisors.

Materials and methods

This retrospective study included pretreatment cone beam computed tomography of 120 patients with malocclusion. Patients were divided into 4 groups (Class I, Class II division 1, Class II division 2 and Class III) according to the subspinale-nasion-supramental (ANB) angle and occlusal relationship. The sagittal root positions, anterior and posterior root-cortical bone angles (AR-CA and PR-CA), root-crown ratios (RCR) and alveolar bone thickness were evaluated.

Results

The sagittal root positions were mainly positioned against the labial cortical plate in the maxillary incisors of the Class II division 2 group and engaged by both the labial and palatal cortical plates in the mandibular incisors of the Class III group. The AR-CA was lower than that in the other groups (P < 0.01) in the maxillary incisors of the Class II division 2 group, and the AR-CA and PR-CA were lower than those in the other groups (P < 0.01) in the mandibular incisors of the Class III group. The alveolar thickness showed no significant difference between the Class II division 1 group and the Class I group (P > 0.05), the middle and lower anterior alveolar thickness (LAAT and MAAT) were lower than those in other groups (P < 0.01) in the maxillary incisors of the Class II division 2 group, and the alveolar thickness at the measurement sites of the middle and lower line were lower than those in other groups (P < 0.01) in the mandibular incisors of the Class III group. The RCR had a moderate positive correlation with the LAAT.

Conclusion

Based on several limitations, this study found that maxillary incisor roots were at risk of penetrating the alveolar bone of Class II division 2 patients, and mandibular incisors may have a relatively small range of safe movement on both the labial and lingual sides of Class III patients during orthodontic treatment.

Periodontal phenotype modification of complexes periodontal-orthodontic case scenarios: A clinical review on the applications of allogenous dermal matrix as an alternative to subepithelial connective tissue graft

OBJECTIVES

The aim of this review is to address the potential applications of allogenous dermal matrix (ADM), as an alternative to subepithelial connective tissue graft (SCTG), in promoting periodontal phenotype modification (PPM) of challenging periodontal-orthodontic clinical scenarios.

OVERVIEW

The rationale behind the need of changing thin to thick gingival tissues is associated to the superior and more stable treatment outcomes promoted by PPM therapy. PPM, via soft tissue grafting, leads to clinical and histological changes of the pre-established original genetic conditions of the gingiva. Although SCTG-based procedures are recognized as the "gold standard" for the treatment of sites requiring root coverage and gingival augmentation, ADM has been recognized as the most suitable alternative to SCTG, particularly in clinical scenarios where the use of autogenous grafts is not possible. Thus, ADM is considered an optimal option for the treatment of patients with a history (or in need) of orthodontic tooth movement, due its two-fold potential indication: (1) the promotion of periodontal soft tissue phenotype modification; and (2) its use, as a barrier membrane, in hard tissues augmentation procedures.

CONCLUSIONS

ADM is a viable option for soft tissue augmentation, as well as for treatment approaches involving buccal bone gain.

CLINICAL SIGNIFICANCE

Periodontal phenotype modification therapy, when applied in challenging periodontal-orthodontic clinical scenarios, promotes root coverage and prevents the onset and development clinical attachment loss.

Efficacy of biologics in root coverage and gingival augmentation therapy: An American Academy of Periodontology best evidence systematic review and network meta-analysis

BACKGROUND

The aim of this systematic review was to assess the efficacy of three biologics, namely autologous blood-derived products (ABPs), enamel matrix derivatives (EMD) and recombinant human platelet-derived growth factor BB (rhPDGF-BB), in root coverage and gingival augmentation therapy.

METHODS

The protocol of this PRISMA 2020-compliant systematic review was registered in PROSPERO (CRD42021285917). After study selection, data of interest were extracted. A network meta-analysis (NMA) was conducted to assess the effect of different surgical interventions on the main clinical outcomes of interest (i.e., mean root coverage [MRC%], complete root coverage [CRC%], keratinized tissue width [KTW], gingival thickness [GT] change, and recession depth [RD] reduction).

RESULTS

A total of 48 trials reported in 55 articles were selected. All studies reported on the treatment of gingival recession defects for root coverage purposes. Forty-six treatment arms from 24 trials were included in the NMA. These arms consisted of treatment with coronally advanced flap (CAF) alone, EMD + CAF, platelet-rich fibrin (PRF) + CAF, and subepithelial connective tissue graft (SCTG) + CAF. Regarding MRC%, SCTG+CAF was associated with a significant higher estimate (13.41%, 95% CI [8.06-18.75], P <  0.01), while EMD+CAF (6.68%, 95% CI [-0.03 to 13.4], P = 0.061) and PRF+CAF (1.03%, 95% CI [-5.65 to 7.72], P = 0.71) failed to show statistically significant differences compared with CAF alone (control group) or with each other. Similarly, only SCTG+CAF led to a significantly higher CRC% (14.41%, 95% CI [4.21 to 24.61], P < 0.01), while treatment arms EMD + CAF (13.48%, 95% CI [-3.34 to 30.32], P = 0.11) and PRF+CAF (-0.91%, 95% CI [-15.38, 13.57], p = 0.81) did not show significant differences compared with CAF alone or with each other. Differences in the CI of PRF+CAF (symmetrical around a zero adjunctive effect) and EMD+CAF (non-symmetrical) suggest that EMD could have some additional value compared with PRF. Treatment with SCTG+CAF led to a statistically significant higher RD reduction (-0.39 mm, 95% CI [-0.55 to 0.22], P < 0.01), however EMD+CAF (-0.13 mm, 95% CI [-0.29 to 0.01], P = 0.08) and PRF+CAF (-0.06 mm, 95% CI [-0.23 to 0.09], P = 0.39) failed to show significant differences compared with CAF or with each other. While SCTG+CAF was associated with a statistically significant higher gain of KTW (0.71 mm, 95% CI [0.48 to 0.93], P < 0.01), EMD+CAF (0.24 mm, 95% CI [-0.02 to 0.51], P = 0.08) and PRF+CAF (0.08 mm, 95% CI [-0.23 to 0.41], P = 0.58) did not result into significant changes compared with CAF alone or with each other. Regarding the use of rhPDGF-BB+CAF, although available studies have reported equivalent results compared with SCTG+CAF, evidence is very limited.

CONCLUSIONS

The use of ABPs, EMD, or rhPDGF-BB in conjunction with a CAF for root coverage purposes is safe and generally promotes significant improvements respective to baseline clinical parameters. However, the adjunctive use of ABPs and EMD does not provide substantial additional improvements in terms of clinical outcomes and patient-reported outcome measures to those achieved using CAF alone, when baseline KTW is >2 mm. Both PRF+CAF and EMD+CAF rendered inferior MRC%, CRC%, RD reduction, and KTW gain compared with SCTG+CAF, which should still be considered the gold-standard in root coverage therapy. Although some studies have reported equivalent results for rhPDGF-BB+CAF compared with the gold-standard intervention, limited evidence precludes formal comparisons with CAF or SCTG+CAF that could be extrapolated to guide clinical practice.

Efficacy of biologics for the treatment of periodontal infrabony defects: An American Academy of Periodontology best evidence systematic review and network meta-analysis

BACKGROUND

A large variety of biomaterials, biologics and membranes have been utilized in the past 40 years for the regenerative treatment of periodontal infrabony defects. Biologic agents have progressively gained popularity among clinicians and are routinely used for periodontal regeneration. In alignment with the goals of the American Academy of Periodontology (AAP) Best Evidence Consensus (BEC) on the use of biologic mediators in contemporary clinical practice, the aim of this sytematic review was to evaluate the effect of biologic agents, specifically autogenous blood-dervied products (ABPs), enamel matrix derivative (EMD) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB), on the regenerative outcomes of infrabony defects.

METHODS

A detailed systematic search was conducted to identify eligible randomized control trials (RCTs) reporting the outcomes of periodontal regenerative therapy using biologics for the treatment of infrabony defects. A frequentist mixed-modeling approach to network meta-analysis (NMA), characterized by the assessment of three individual components for the treatment of an infrabony defect (the bone graft material [BG], the biologic agent, the application of a barrier membrane) was performed to evaluate and compare the relative efficacy of the different components, on the outcomes of different therapeutic modalities of periodontal regeneration.

RESULTS

A total of 153 eligible RCTs were included, with 150 studies contributing to the NMA. The quantitative analysis showed that the addition of biologic agents to bone graft significantly improves the clinical and radiographic outcomes, as compared to BG and flap procedures alone. Barrier membranes enhanced the regenerative outcomes of BG but did not provide further benefits in combination with biologics. The type of BG (autogenous, allogeneic, xenogeneic or alloplastic) and the biologic agent (EMD, platelet-rich fibrin [PRF], platelet-rich plasma [PRP] or rhPDGF-BB) played a significant role on the final outcomes of infrabony defects. Allogeneic and xenogeneic BGs exhibited statistically significantly superior clinical gain than synthetic and autogenous BGs (p < 0.05 in all the comparisons), while rhPDGF-BB and PRF demonstrated significantly higher stability of the gingival margin (p < 0.01) and radiographic bone fill/gain (p < 0.05), together with greater, although not statistically significant, clinical attachment level gain and pocket depth reduction, than EMD and PRP. Overall, rhPDGF-BB exhibited the largest effect size for most parameters, including clinical attachment level gain, pocket depth reduction, less gingival recession and radiographic linear bone gain. Considering the relatively high number of trials presenting an unclear or high risk of bias, the strength of recommendation supporting the use of PRP was judged weak, while the recommendation for EMD, PRF and rhPDGF-BB was deemed in favor.

CONCLUSIONS

Biologics enhance the outcomes of periodontal regenerative therapy. Combination therapies involving BGs + biologics or BGs + barrier membrane demonstrated to be superior to monotherapies. The choice of the type of BG and biologic agent seems to have significant impact on the clinical and radiographic outcomes of infrabony defects.

Difference in the alveolar bone remodeling between the adolescents and adults during upper incisor retraction: a retrospective study

The purpose of this study was to compare the difference of alveolar bone remodeling between the adolescents and adults in the maxillary incisor area during retraction. This retrospective study included 72 female patients who needed moderate anchorage to correct the bimaxillary protrusion. Subjects were further divided into the minor group (n = 36, 11-16 years old) and adult group (n = 36, 18-35 years old). Digital lateral cephalography and cone beam CT scanning were taken in each patient before (T0) and after treatment (T1). Cephalometry was conducted to assess incisor retraction, while alveolar bone thickness (ABT), alveolar bone distance (ABD), and alveolar bone area (ABA) were detected to assess changes in the alveolar bone. No difference in the inclination of upper incisors was observed at both T0 and T1 between two groups. Changes in the alveolar bone showed a similar tendency with bone apposition on the labial side and bone resorption on the palatal side in both groups. Less increase in the labial ABT (T1-T0) and more decrease in the palatal ABT (T1-T0) was found in the adult group, leading to less total ABT in the adult group. Higher reduction in ABD (T1-T0) was found in the adult group. Moreover, more decrease in the ABA (T1-T0) was found in the adult group. Adult patients have less alveolar bone support after treatment when compared with young adolescents. Orthodontists should take the age into consideration to reduce the potential periodontal risks during the treatment planning.

Double Lateral Sliding Bridge Flap versus Laterally Closed Tunnel for the Treatment of Single Recessions in the Mandibular Anterior Teeth: A Pseudorandomized Clinical Trial

(1) Background: This study compared the clinical and esthetic results of the double lateral sliding bridge flap (DLSBF) and the laterally closed tunnel (LCT) techniques, with a subepithelial connective tissue graft (SCTG), for the treatment of single Miller class II-III recessions in the mandibular anterior teeth. (2) Methods: This pseudorandomized clinical trial evaluated 14 patients, 7 of whom were part of the DLSBF + SCTG group, with an average follow-up of 58.7 ± 24.0 months, and 7 of whom were in the LCT + SCTG group, with an average follow-up of 16.7 ± 3.3 months. Clinical and esthetic evaluations of the following parameters were performed and the results for the two groups were compared: gingival recession depth, probing depth, keratinized tissue width, gingival thickness, percentage of root coverage and root coverage esthetic score. (3) Results: After the follow-up period, each technique provided evidence of a reduction in recession depth and clinical attachment level, as well as increased keratinized tissue width and gingival thickness, with statistically significant differences (p < 0.05). The analysis showed that gingival recession depth decreased less in the DLSBF group (4.3 ± 1.2 mm to 0.6 ± 1.1 mm) than it did in the LCT group (4.9 ± 1.1 mm to 0.1 ± 0.4 mm), but no significant difference was found between the two groups. Similarly, a greater reduction in the clinical attachment level parameter was observed in the LCT group, while a greater increase in gingival thickness was observed in the DLSBF group. The presence of scars was the only parameter for which statistically significant differences (p < 0.05) between the two study groups were found. (4) Conclusions: Within the limitations of the study, it indicates that the LCT + SCTG technique may be considered an optimal technique in terms of reducing gingival recession depth, complete root coverage and esthetic results for the treatment of single gingival recessions in the mandibular anterior teeth.

Evaluation of the Hyaluronic Acid Versus the Injectable Platelet-Rich Fibrin in the Management of the Thin Gingival Phenotype: A Split-Mouth Randomized Controlled Clinical Trial

Background Several procedures have been used to enhance thin gingival phenotype and the majority of these procedures have been surgical. A new minimally invasive approach that involved multiple injections of platelet-rich fibrin (i-PRF) to enhance the thin gingival phenotype has been proposed. As the hyaluronic acid (HA) and the i-PRF share similar properties in terms of promoting periodontal regeneration, the present trial aimed to evaluate the effectiveness of multiple injections of the i-PRF in patients with thin gingival phenotypes in comparison with those of the HA in increasing the gingival thickness (GT) and the keratinized tissue width (KTW). Materials and methods Eighty-four sites from 14 systematically healthy patients who had thin gingival phenotypes (GT ≤1 mm) were included in this split-mouth randomized controlled trial. For each patient, each side of the anterior mandible was randomly allocated to one of the two materials (HA or i-PRF). In the HA group, the selected sites of the gingiva were injected with cross-linked HA using a 30-gauge microneedle. In the i-PRF group, the i-PRF was injected in the same manner. This procedure was repeated in both groups three times with intervals of 7 days. The GT, KTW, and periodontal indices: gingival index (GI), bleeding on probing (BOP), and probing depth (PD) were measured at baseline, 1 month, and 3 months following the initial injection. Results The GT increased significantly in both groups at the three assessment times (p<0.001). The KTW also showed a statistically significant increase in the intragroup comparisons in both groups (p<0.05). No statistically significant difference was observed between the two groups at the three assessment times for the GT and the KTW (p>0.05). The GI significantly decreased after 1 month and 3 months compared to the baseline values in both groups (p<0.05). The intergroup comparisons for the GI revealed no statistically significant differences at the three assessment times (p>0.05). As for the BOP and the PD, no statistically significant differences were found between the three assessment times (p>0.05) and between the two groups at each assessment time (p>0.05). Conclusion Multiple injections of the i-PRF and the HA in the thin gingival phenotype resulted in an increased GT and increased KTW, with no statistically significant differences between the two methods. Both minimally invasive techniques were more effective in improving the GT rather than the KTW.

Nomogram prediction of vulnerable periodontal condition before orthodontic treatment in the anterior teeth of Chinese patients with skeletal Class III malocclusion

OBJECTIVE

To establish and verify models predictive of thin periodontal phenotype and alveolar fenestration/dehiscence in the anterior teeth of patients with skeletal Class III malocclusion.

MATERIAL AND METHODS

Retrospective data of 669 anterior teeth (305 in maxillae and 364 in mandibles) from 80 patients with skeletal Class III malocclusion before augmented corticotomy were collected. Distribution of thin periodontal phenotype and alveolar fenestration and dehiscence were evaluated and their associations with potential influencing factors were explored using univariate and multivariate analyses. The predictive models were visualized as nomograms, the accuracy of which was tested by receiver operating curve analyses.

RESULTS

Thin phenotype was associated with Mazza bleeding index, sex, tooth type, probing depth and width of keratinized gingiva (WKG). Labial dehiscence was associated with age, jaw, labial bone thickness, mandibular plane angle, sagittal root position (SRP), sex, tooth type, and WKG. Labial fenestration was associated with sex, tooth type, SRP, and periodontal phenotype. The areas under the curves of nomogram prediction models for periodontal phenotype, alveolar dehiscence, and alveolar fenestration were 0.84, 0.81, and 0.73, respectively.

CONCLUSIONS

Female sex, lateral incisor, and limited WKG may be risk factors for thin periodontal phenotype. Age, canine, male sex, mandible, thin labial bone thickness, and root positioned against the labial plate may be risk factors for labial dehiscence; and female sex, thick phenotype, root positioned against the labial plate, lateral incisor, and canine may be risk factors for labial fenestration. The predictive performance of the models was acceptable.

Two decades of research on CBCT imaging in DMFR - an appraisal of scientific evidence

OBJECTIVE

This article aims to appraise how scientific evidence related to CBCT has changed over the years, based on levels of evidence and diagnostic efficacy.

METHODS

A general search strategy was used in different databases (Pubmed, Embase, and Web of Science) to identify systematic reviews (SRs) on CBCT until November of 2020. The SRs included were divided according to different specialties of dentistry. A critical review of the articles was made, describing the level of evidence and efficacy.

RESULTS

In total, 75 articles were selected. There was an increase in the number of SRs on CBCT from 2014 onwards, as 83% of the SRs on this topic were published after 2013, and 72% between 2016 and to date. Twenty SRs (27%) performed meta-analysis. Only 28% of the SRs provided a detailed description of CBCT protocols. According to SR evidence, almost all specialties of dentistry have advanced concomitantly with the introduction of CBCT. The majority of SRs were related to clinical applications (level 2 of efficacy), followed by technical parameters (level 1 of efficacy). Only some CBCT models were mentioned in the SRs selected.

CONCLUSION

Over the course of 20 years, SRs related to CBCT applications for a broad range of dental specialties have been published, with the vast majority of studies at levels 1 and 2 of diagnostic efficacy. Not all CBCT models available on the market have been scientifically validated. At all times, one should remain cautious as such not to simply extrapolate in vitro results to the clinical setting. Also, considering the wide variety of CBCT devices and protocols, reported results should not be overstated or generalized, as outcomes often refer to specific CBCT devices and protocols.

Modern 3D cephalometry in pediatric orthodontics-downsizing the FOV and development of a new 3D cephalometric analysis within a minimized large FOV for dose reduction

OBJECTIVES

Dose reduction achieved by downsizing the field of view (FOV) in CBCT scans has brought no benefit for pediatric orthodontics, until now. Standard 2D or 3D full-size cephalometric analyses require large FOVs and high effective doses. The aim of this study was to compare a new 3D reduced-FOV analysis using the Frankfurt horizontal (FH) plane as reference plane with a conventional full-size analysis using the Sella-Nasion (S-N) plane as reference plane.

MATERIALS AND METHODS

Thirty-eight CBCT data sets were evaluated using full- and reduced-FOV analysis. The measurements of a total of 20 skeletal and dental standard 3D full-size variables were compared with the measurements of 22 corresponding 3D reduced-FOV variables. Statistical analysis was performed to prove mathematic relation between standard and alternative variables. Regression analyses were carried out.

RESULTS

Coefficients of determination (R²) between 0.15 and 0.95 (p < 0.001-0.055) were described. All variables showed obvious relations of different strength except for SNA and its alternative Po_R-Or_R-A (°) (R² = 0.15, p = 0.055), but a second variable Ba_A (mm) showed stronger relation (R² = 0.28, p = 0.003).

CONCLUSIONS

All standard variables related to the reference plane S-N could be described with alternative variables related to the FH. Further research should define more reliable landmarks for coordinate systems and reference points.

CLINICAL RELEVANCE

Minimized large FOVs meet the demand of 3D cephalometric analyses and enable the application of CBCT scans in pediatric orthodontic patients in many specific indications. Dose reduction is accompanied by increasing access to all the advantages of 3D imaging over 2D imaging.

Changes in alveolar bone morphology after traction of buccally vs palatally unilateral maxillary impacted canines: A cone-beam computed tomography study

INTRODUCTION

The objective of this study was to evaluate the 3-dimensional changes in alveolar bone morphology after traction of buccally vs palatally unilateral maxillary impacted canines (MIC).

METHODS

Following a split-mouth model, 27 cone-beam computed tomography images of unilaterally MIC (14 palatally and 13 buccally) and 27 contralateral unimpacted controls were obtained before and after traction using nickel-titanium closed-coil springs and a rigid anchorage appliance. Alveolar bone height and width were measured in the axial, coronal, and sagittal slides by 3 calibrated orthodontists, taking into account the impaction characteristics. A t test was used to compare the 2 groups, and a paired t test was applied for intragroup comparisons (both sides). A multiple linear regression model was used to evaluate the influence of the predictor variables on alveolar bone dimensional changes.

RESULTS

The alveolar height showed a significantly greater decrease in palatally MIC (2.09 to 2.79 mm) than buccally MIC (0.28 to 0.57 mm) (P <0.05) for all surfaces. However, the alveolar width increased similarly in both groups up to 1.36 mm. In general, the affected side had a more significant height loss and greater increases in alveolar width than the nonaffected side. Regression analysis indicated that buccally MIC and age decreased alveolar changes, whereas female sex increased alveolar changes (P <0.05).

CONCLUSIONS

MIC traction with nickel-titanium closed-coil springs and heavy anchorage induces significant 3-dimensional changes in alveolar bone characterized by alveolar bone height decreases and cervical alveolar bone width increases. The height decrease is greater in palatally than in buccally MIC.

Displacement in root apex and changes in incisor inclination affect alveolar bone remodeling in adult bimaxillary protrusion patients: a retrospective study

BACKGROUND

Periodontal health is of great concern for periodontists and orthodontists in the inter-disciplinary management of patients with bimaxillary protrusion. The aim of present study is to investigate changes in the alveolar bone in the maxillary incisor region and to explore its relationship with displacement of root apex as well as changes in the inclination of maxillary incisors during incisor retraction.

METHODS

Samples in this retrospective study consisted of 38 patients with bimaxillary protrusion. Cone-beam computed tomography (CBCT) images was taken before(T0) and after (T1) treatment. Alveolar bone thickness (ABT), height (ABH) and area (ABA) were utilized to evaluate changes in the alveolar bone, while incisor inclination and apex displacement were used to assess changes in the position of maxillary central and lateral incisors. Correlations between alveolar bone remodeling and apex displacement as well as changes in the inclination were investigated.

RESULTS

The labial ABT of central and lateral incisors at the mid-root third was increased. In contrast, the palatal ABT at crestal, mid-root and apical third level were consistently decreased. ABH was not altered on the labial side, while significantly decreased on the palatal side. ABA was not significantly increased on the labial side, but significantly decreased on the palatal side, leading to a significantly reduced total ABA. Orthodontic treatment significantly reduced inclination of upper incisors. Changes in the amount (T1-T0) of ABA was remarkably correlated with apex displacement and changes of inclination (T1-T0); in addition, using the multivariate linear regression analysis, changes of ABA on the palatal side (T1-T0) can be described by following equation: Changes of palatal ABA (T1-T0) = - 3.258- 0.139× changes of inclination (T1-T0) + 2.533 × apex displacement (T1-T0).

CONCLUSIONS

Retraction of incisors in bimaxillary protrusion patients may compromise periodontal bone support on the palatal side. An equation that incorporated the displacement of root apex and change in the incisor inclination may enable periodontist-orthodontist interdisciplinary coordination in assessing treatment risks and developing an individualized treatment plan for adult patients with bimaxillary protrusion. Moreover, the equation in predicating area of alveolar bone may reduce the risks of placing the teeth out of the bone boundary during 3D digital setups.

Surgical Considerations and Decision Making in Surgically Facilitated Orthodontic Treatment/Periodontally Accelerated Osteogenic Orthodontics

FOCUSED CLINICAL QUESTION

Surgically facilitated orthodontic treatment (SFOT)/periodontally accelerated osteogenic orthodontics (PAOO) has the potential of allowing safer orthodontic treatment in vulnerable periodontium with thin phenotypes. SFOT/PAOO is a phenotype modification therapy (PhMT) approach where thin bone morphotype and/or gingiva are surgically augmented to convert a fragile-thin to a robust-thick periodontal environment. This permits orthodontic treatment in these previously thin phenotype cases to proceed without iatrogenically-induced adverse effects. This is an infrequently performed procedure with few available clinical recommendations.

SUMMARY

In this practical application paper, three clinicians with the collective clinical experience of over 1500 SFOT cases developed a clinical decision-making algorithm outlining the key steps for SFOT. A sample case is provided for clinical appreciation of the procedure. Lastly, this panel reviewed and detailed the critical decision making and surgical approaches associated with the use of SFOT. Though the basic decision making is consistent, individual variations on surgical management are compared. This is summarized in a clinical decision tree along with a sample clinical case. Additionally, the cumulative experience has been organized into tables that provide comparative decision and surgical approaches. There are similarities and differences. Lastly, strategies that have not been individually effective are also noted.

CONCLUSION

SFOT/PAOO is an effective PhMT approach whereby the bone and/or soft tissue phenotype can be surgically modified to permit orthodontic treatment in patients with thin phenotypes. The cumulative experience of three experienced clinicians provides clinical recommendations for SFOT management of PhMT for pre-orthodontic treatment.

Alveolar bone changes in maxillary and mandibular anterior teeth during orthodontic treatment: A systematic review and meta-analysis

The association between tooth movement and remodelling of surrounding bone is controversial. To analyse the effect of tooth movement on alveolar bone changes in maxillary and mandibular anterior teeth by cone-beam computed tomography (CBCT). The Embase, Cochrane Library and Medline databases were searched without any language restrictions. Longitudinal studies using CBCT to observe alveolar bone changes of maxillary and mandibular anterior teeth during orthodontic treatment were included. Two independent reviewers performed the study selection, data extraction and methodological quality assessment. A total of 26 studies were included in this review, 14 of which were eligible for quantitative synthesis. In extraction cases, meta-analysis showed vertical bone loss on the labial (0.36 mm) and lingual (0.94 mm) sides of maxillary incisors, and lingual bone thickness decreased significantly at the cervical level (0.57 mm). In non-extraction cases, vertical alveolar bone loss was significant on the labial side (0.97 mm) and lingual side (0.86 mm) of mandibular incisors. Subgroup analysis for skeletal class III patients indicated that vertical alveolar bone loss was 1.16 mm on the labial side and 0.83 mm on the lingual side of mandibular incisors. The absence of high-quality studies and the high heterogeneity of the included studies were limitations of this systematic review and meta-analysis. Based on limited evidence, alveolar bone height and thickness, especially at the cervical level, decreased during both labial and lingual movement of anterior teeth.

Surgically Facilitated Orthodontic Therapy (SFOT): Diagnosis and Indications in Interdisciplinary Dentofacial Therapy Involving Tooth Movement

FOCUSED CLINICAL QUESTION

What are the key considerations for the interdisciplinary dentofacial therapy (IDT) team in the diagnostic process to evaluate a patient for surgically facilitated orthodontic therapy (SFOT)?

SUMMARY

SFOT creates a demineralized bone matrix and augments dentoalveolar deficiencies in the management of dentofacial disharmony malocclusion. Numerous indications and contraindications exist which are essential to the periodontal surgeon for proper case selection. A collaboratively focused workup by an IDT team is equally essential. Cone beam computed tomography (CBCT) and orthodontic simulation software which identifies changes in the dentoalveolar complex influenced by tooth movement are critical in providing transparency to the patient and IDT team during the treatment planning process. Such transparency can aid the team in assessing goals and outcomes that consider and respect foundational dentoalveolar parameters while contributing to sustainable outcomes.

CONCLUSIONS

The SFOT IDT decision making process is complex, yet full of opportunities. Embracing SFOT IDT with innovative and novel 3D technology can optimize conditions leading to long-term outcomes that align with periodontal stability as well as patient goals and preferences which permeate beyond the achievement of "straightening teeth". Transparency of complex IDT through 3D CBCT and orthodontic simulation software engenders "collaborative accountability" and can improve patient communication which is critical to developing meaningful and essential treatment plans.

Differential alveolar bone modeling after orthodontic retraction

BACKGROUND

Distinct, irregular, and hard nodular protuberances similar to the morphologic features of exostoses can occasionally be noted on the labial surface of the alveolar bone after orthodontic retraction of anterior teeth in adults. These have long been believed to be exostoses developed in response to loading. However, specific characterization of this phenomenon has not been documented.

CASE DESCRIPTIONS

Three cases of patients displaying multiple irregular labial bony protuberances after retraction of anterior teeth are reported. These protuberances appeared during retraction and became more prominent with additional retraction. Serial clinical photographs, lateral cephalograms, digital models, and cone-beam computed tomography scans were evaluated. On the basis of 3-dimensional superimpositions of digital models and cone-beam computed tomographic scans, the irregular protuberances appear to be the result of differential alveolar bone modeling, with more resorption of bone covering the tooth root than that of interdental bone, and not of true bone overgrowth or deposition (that is, exostoses).

CONCLUSION AND PRACTICAL IMPLICATIONS

Orthodontic patients often seek treatment to improve occlusion as well as esthetics. Although this study shows that these protuberances are the result of differential modeling, they may still be perceived by patients as "outgrowths," which may cause concerns related to esthetics or comfort. Clinicians should note that these protuberances are a possible outcome when large amounts of bodily retraction and root movement of anterior teeth are planned. Patients who experience psychosocial problems with this phenomenon may be candidates for alveoloplasty.

Is periodontal phenotype modification therapy beneficial for patients receiving orthodontic treatment? An American Academy of Periodontology best evidence review

BACKGROUND

Orthodontic treatment can greatly impact the periodontium, especially in dentitions with a thin periodontal phenotype. Orthodontic tooth movement can result into iatrogenic sequelae to these vulnerable anatomic conditions, such as development and exacerbation of bony dehiscence or fenestration defects, which can manifest loss of periodontal support and gingival recession (GR). This systematic review aimed to investigate whether periodontal phenotype modification therapy (PhMT) involving hard tissue augmentation (PhMT-b) or soft tissue augmentation (PhMT-s) has clinical benefits for patients undergoing orthodontic treatment.

METHODS

An electronic search was performed in two major databases for journals published in English language from January 1975 to January 2019 and a hand search of printed journals was also performed to identify human clinical trials reporting clinical and radiographic outcomes of patients receiving orthodontic treatment with or without hard and soft tissue augmentation procedures. Data were extracted and organized into tables for qualitative assessment.

RESULTS

Eight studies were identified evaluating the outcomes of PhMT in patients undergoing orthodontic therapy. Six studies evaluated patients receiving PhMT-b via corticotomy-assisted orthodontic therapy (CAOT) and simultaneous bone augmentation while the other two received PhMT-s before tooth movement. No studies investigated PhMT-b alone without CAOT and most studies focused on the mandibular anterior decompensation movements. There was high heterogeneity in the study design and inconsistency of the reported outcomes; therefore, a meta-analysis was not performed. Evidence at this moment supports CAOT with hard tissue augmentation accelerated tooth movement. However, only two studies provided direct comparison to support that CAOT with PhMT-b reduced the overall treatment time compared with conventional orthodontic treatment. No periodontal complications or evidence of severe root resorption were reported for both groups. Four studies provided radiographic assessment of the PhMT-b and demonstrated increased radiographic density or thicker facial bone after the treatment. Two studies reported an expanded tooth movement. One study reported an increase in keratinized tissue width post-CAOT plus PhMT-b, while another study with a 10-year follow-up showed a lower degree of relapse using the mandibular irregularity index when compared with conventional tooth movement alone. Two studies examined the effect of PhMT-s before orthodontic treatment. Unfortunately, no conclusions can be drawn because of the limited number of studies with contradicting outcomes.

CONCLUSIONS

Within the limited studies included in this systematic review, PhMT-b via particulate bone grafting together with CAOT may provide clinical benefits such as modifying periodontal phenotype, maintaining or enhancing facial bone thickness, accelerating tooth movement, expanding the scope of safe tooth movement for patients undergoing orthodontic tooth movement. The benefits of PhMT-s alone for orthodontic treatment remain undetermined due to limited studies available. However, PhMT-b appears promising and with many potential benefits for patients undergoing orthodontic tooth movement. There is a need for a higher quality of randomized controlled trials or case control studies with longer follow-up to investigate the effects of different grafting materials and surgical sites other than mandibular anterior region.

Analysis of Alveolar Bone Morphology of the Maxillary Central and Lateral Incisors with Normal Occlusion

Background and objectives: This study investigated the morphology of the labial and palatal bony wall of the maxillary central and lateral incisors using cone-beam computed tomography (CBCT). The difference between males and females and the measurement between right and left sides were measured. Materials and Methods: Twenty participants, consisting of 11 females and 9 males having normal occlusion, were used for the analysis. The mean age was 21.9 ± 3.0 years. The thickness of the labial bony wall and palatal bony wall, perpendicular to the long axis of the root, were evaluated at 3 and 5 mm apical from the cemento-enamel junction (CEJ) and at the root apex. The available bony wall below the apex of the central and lateral incisors, and the angulation between the long axis of the tested tooth and outer surface of the labial bone were measured. Results: The mean labial bony wall thickness at the 3 and 5 mm apical from the CEJ were 1.1 ± 0.3 mm and 1.0 ± 0.4 mm for central incisors, respectively, as well as 1.2 ± 0.4 mm and 1.0 ± 0.4 mm for lateral incisors, respectively. The mean palatal bony wall thickness at 5 mm from the CEJ was above 2 mm in the central and lateral incisors. The percentage of labial bony wall thickness 2 mm or greater at the root apex in central incisors was higher than in lateral incisors (62.5% vs. 55.0%). The percentage of palatal bony wall thickness ≥2 mm at 3 mm apical from the CEJ in the central incisors was higher than in the lateral incisors (37.5% vs. 15.0%). The results on the left and right sides did not show statistically significant differences, except in the labial and palatal bony wall thickness at 3 mm from the CEJ in the lateral incisor. Generally, no significant differences were seen between males and females, but males had a significantly higher labial bony wall thickness at 3 and 5 mm from the CEJ in the central and lateral incisors when compared with females. Conclusions: This study showed that a majority of the cases of Korean participants had less than 2 mm of labial bony wall thickness at 3 and 5 mm apical from the CEJ at central and lateral incisors, and this should be kept in mind while performing dental practices, including tooth extraction or immediate implantation in anterior regions. Preoperative analysis using CBCT may be beneficial for establishing the treatment plan.

Outcome of periodontal–orthodontic treatment in subjects with periodontal disease. Part II: a CBCT study of alveolar bone level changes

Aim

To examine alveolar bone level (ABL) changes before (T1) and after (T2) orthodontic treatment (OT) in subjects with periodontal disease.

Methods

The study included 50 subjects with periodontal disease. All patients received subgingival debridement following baseline examination. Control group patients received final periodontal treatment before the start of OT. For the test group patients final periodontal treatment was performed simultaneous to OT. OT was performed with a straight-wire appliance. Micro-implants or temporary crowns on implants were used for posterior anchorage when needed. ABL measurements of 3821 tooth surfaces were performed on cone beam computed tomography images.

Results

No difference was observed between mean ABL at T1 and T2. ABL remained unchanged on 69 per cent of surfaces. A mean of 15.6 (SD 7.4) per cent of surfaces experienced ABL gain, and a mean of 15.1 (SD 7.5) per cent was found with ABL loss. Small significant median ABL difference was observed on mesial and distal surfaces (P < 0.001). A significant difference was found between median ABL changes on mesial/distal in comparison to buccal/lingual surfaces (P < 0.01). Significantly more buccal (17.9 %) and lingual (18.5 %) surfaces experienced ABL loss when compared with mesial (11.3 %) and distal (12.0 %) surfaces (P < 0.001). Significant difference was found in the median ABL change of intruded (0.5 (IQR 0.94) mm) and non-intruded (−0.4 (IQR 1.07) mm) maxillary incisors (P = 0.04). Significant median ABL gain was found on the lingual surface of maxillary incisors, which were retroclined more than 8.6 degree and intruded more than 1.6 mm.

Conclusions

ABL changes after periodontal–orthodontic treatment in patients with periodontal disease were small. ABL gain was more observed on mesial and distal surfaces and ABL loss on buccal and lingual surfaces. Larger orthodontic movements of maxillary incisors influenced ABL gain.

Bone regeneration after alveolar dehiscence due to orthodontic tooth movement – A case report

This article presents the orthodontic treatment of a 15 year old male patient with an Angle class I malocclusion with a class II skeletal base, lower incisor proclination along with a hyperdivergent facial pattern. Such situations that involve camouflage treatment, usually results in further lower incisor proclination which can be reduced to an extent by adding buccal root torque. Placement of additional torque in this case however, resulted in positioning of the root apex of the lower right lateral incisor outside the alveolar housing, although no gingival signs were present. The mechanics were then reversed and at the end of 21 months of treatment, the apices were back within the alveolar housing. A 4-year post-treatment cone-beam computed tomography showed normal bone coverage of the affected tooth; and no clinical signs of gingival pathology were present. Orthodontists should be aware of possible complications of excessively torqueing lower incisors in order to prevent proclination. If root apices are inadvertently moved through the cortex, a good long-term prognosis is possible using orthodontics alone by reversing the mechanics, if no gingival complications are present.

Outcome of orthodontic treatment in subjects with periodontal disease. Part III: a CBCT study of external apical root resorption

Background

No evidence is present on the risk for external apical root resorption (EARR) during orthodontic treatment (OT) of adult patients with periodontal disease.

Aim

To examine EARR after OT in subjects with periodontal disease and to analyse how intrusion and change in inclination of the most proclined maxillary incisors influence EARR.

Methods

The study included 50 patients with periodontal disease. Sub-gingival debridement by ultrasonic instrumentation supplemented with hand instruments was performed by experienced dental hygienist after baseline examination for all patients. For the control group, final periodontal treatment (PT) was performed before orthodontic tooth movement. For the test group patients, final PT was performed after levelling and alignment phases were finished, before the active space closure with elastic chain and/or inter-arch elastic traction for sagittal correction was started. OT was performed with a straight-wire appliance. Micro-implants or implants were used for posterior anchorage. Cone beam computed tomography examinations were performed before and after OT. EARR of all single-rooted teeth were measured. EARR of the most proclined maxillary incisor was related to intrusion and change in inclination angle.

Results

EARR after OT was observed in median 80.7 per cent (interquartile range 22.02) of single-rooted teeth [mean 1.2 (standard deviation 0.44) mm]. In 82.3 per cent of teeth, EARR was 2 mm or less. Severe EARR was found in 8 per cent of patients and five maxillary incisors (less than 1 per cent of all teeth). The amount of intrusion and change in inclination angle of the most proclined maxillary central incisor influenced the extent of EARR. Mean EARR was significantly higher when OT lasted more than 18 months (P = 0.02).

Conclusions

OT in conjunction with PT in periodontal patients resulted in EARR in 81 per cent of all single-rooted teeth. Intrusion and change in inclination angle of the most proclined maxillary central incisor influenced the extent of EARR, as did longer OT.

Role of Cone-Beam Computed Tomography in the Management of Periodontal Disease

The goal of this paper was to review the current literature surrounding the use of cone beam computed tomography (CBCT) related to the diagnosis, prognostic determination, and treatment of periodontal diseases. A literature review was completed to identify peer-reviewed articles related to CBCT and periodontics. The results were filtered to pool only articles specific to CBCT and periodontal diagnosis, prognosis, and treatment/outcomes. The articles were reviewed and findings summarized. Author’s commentary on technological advances and additional potential uses of CBCT in the field of periodontics were included. There is evidence to suggest that CBCT imaging can be more accurate in diagnosing specific periodontal defects (intrabony and furcation defects), and therefore be helpful in the prognostic determination and treatment planning. However, at this time, CBCT cannot be recommended as the standard of care. It is up to the individual clinician to use one’s own judgment as to when the additional information provided by CBCT may be beneficial, while applying the As Low As Reasonably Achievable (ALARA) principle. With continued technological advances in CBCT imaging (higher resolution, reduced imaging artifacts, lower exposure, etc.) the author’s believe that CBCT usage will become more prominent in diagnosis and treatment of periodontal diseases.