The thickness of alveolar bone at the maxillary canine and premolar teeth in normal occlusion

Optical thickness measurement of occluded samples by lens-less Fourier transform digital holography, thermal loading, and machine learning

Thickness measurements of objects, especially transparent and semi-transparent objects, are essential for their characterization and identification. However, in the case of occluded objects, the optical thickness determination becomes difficult, and an indirect way must be devised. Thermal loading of the objects changes their opto-thermal properties, which will be reflected as a change in their optical thickness. The key to quantifying such occluded objects lies in collecting these opto-thermal signatures. This could be achieved by imaging the changes occurring to a probe wavefront passing through the object while it is being thermally loaded. Digital holographic interferometry is an ideal tool for observing phase changes, as it can be used to compare wavefronts recorded at different instances of time. Lens-less Fourier transform digital holographic imaging provides the phase information from a single Fourier transform of the recorded hologram and can be used to quantify occluded phase objects. Here we describe a technique for the measurement of change in optical thickness of thermally loaded occluded phase samples using lens-less Fourier transform digital holography and machine learning. The advantage of the proposed technique is that it is a single shot, lens-less imaging modality for quasi-real-time quantification of phase samples behind thin occlusions.

Evaluation of cuspid cortical anchorage with different sagittal patterns using cone-beam computed tomography: a retrospective study

BACKGROUND

No studies have focused on cortical anchorage resistance in cuspids, this study aimed to characterize the cortical anchorage according to sagittal skeletal classes using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 104 men and 104 women were divided into skeletal class I, II, and III malocclusion groups. Skeletal and dental evaluations were performed on the sagittal and axial cross-sections. One-way analysis of variance followed by least significant difference post-hoc tests was used for group differences. Multiple linear regression was performed to evaluate the relationship between influential factors and cuspid cortical anchorage.

RESULTS

All cuspids were close to the labial bone cortex in different sagittal skeletal patterns and had different inclinations. There was a significant difference in the apical root position of cuspids in the alveolar bone; however, no significant difference in the middle or cervical portions of the root was found between different sagittal facial patterns. The middle of the cuspid root was embedded to the greatest extent in the labial bone cortex, with no significant difference between the sagittal patterns. For all sagittal patterns, 6.03 ± 4.41° (men) and 6.08 ± 4.45° (women) may be appropriate root control angles to keep maxillary cuspids' roots detached from the labial bone cortex.

CONCLUSIONS

Comparison of skeletal class I, II, and III malocclusion patients showed that dental compensation alleviated sagittal skeletal discrepancies in the cuspid positions of all patients, regardless of the malocclusion class. Detailed treatment procedures and clear treatment boundaries of cuspids with different skeletal patterns can improve the treatment time, periodontal bone remodeling, and post-treatment long-term stability. Future studies on cuspids with different dentofacial patterns and considering cuspid morphology and periodontal condition may provide more evidence for clinical treatment.

Application of computer-aided design and 3D-printed template for accurate bone augmentation in the aesthetic region of anterior teeth

PURPOSE

To explore the outcomes of bone augmentation in the aesthetic zone of the anterior teeth using computer-aided design and a 3D-printed template.

METHODS

Ten patients with severe bone defects in the aesthetic zone of anterior teeth were included in the study; CT data were collected before surgery. The design of the osteotomy line in the bone defect area was determined under computer simulation. The position parameters and osteotomy line of the free bone were determined via virtual surgery. A 3D-printed template was prepared to guide the accurate placement of the bone graft. Reexamination was conducted to evaluate the position of the bone graft immediately after the operation and the resorbed capacity of the bone graft before implant restoration.

RESULTS

The position of the bone graft was consistent with the preoperative design. The amount of bone graft resorbed was within the acceptable range three months after the operation, and the effect of implant restoration was satisfactory.

CLINICAL SIGNIFICANCE

Use of computer-aided design and a 3D-printed template can be an effective approach for accurate bone augmentation in the aesthetic zone of the anterior teeth.

Buccal and palatal alveolar bone dimensions in the anterior maxilla: A micro-CT study

OBJECTIVE

Anterior maxillary immediate implant placement has become a popular procedure. It has aesthetic and functional risks. A prerequisite for success is sufficient alveolar bone for primary stability. Many cone-beam computed tomography (CBCT) studies have assessed alveolar bone dimensions in the anterior maxilla, with varying results. More accurate information on the alveolar bone dimensions in the anterior maxilla is required. The objective of the present study was to evaluate bone dimensions in the anterior maxilla using micro-CT, a high-resolution imaging tool.

MATERIALS AND METHODS

Seventy-two human skulls were scanned using micro-CT at the South African Nuclear Energy Corporation. Specialized software was used for 3-D rendering, segmentation, and visualization of the reconstructed volume data. Axial planes were created over each alveolus/tooth from canine to canine. Buccal and palatal bone dimensions were measured at crestal, 3 mm, 6 mm, and 9 mm levels.

RESULTS

Buccal bone rarely exceeded 0.5 mm, consisting of bundle bone only for all investigated teeth at all levels. Up to a third of teeth showed buccal fenestrations. Alveolar bone on the palatal side was thicker than buccal and increased from <1 mm at crestal level up to 3.77 mm, 4.56 mm, and 5.43 mm for centrals, laterals, and canines at the 9 mm level, respectively.

CONCLUSIONS

Immediate implants in the anterior maxillae has anatomical risks. Alveolar bone on the buccal aspect is very thin, with fenestrations in certain positions. Therefore, a thorough planning and individual approach are needed to avoid possible complications and achieve stable aesthetic and functional results in the long-term.

Morphologic Evaluation of Dentoalveolar Structures after Corticotomy-Assisted Orthodontic Treatment in Romanian Adult Patients

Background and Objectives: Corticotomy-facilitated orthodontics is an approach that can be useful in treating complex orthodontic cases and that could enhance the rate of tooth movement. The aim of this study was to evaluate the changes that occurred in the buccal cortical bone and at the root level after an orthodontic treatment when corticotomy was used, in Romanian patients. Materials and Methods: After dividing the subjects into two groups (maxillary and mandibular corticotomy), based on CBCT, measurements were made of the thickness of the cortical buccal bone at the cervical, median and apical level, and of the root length at T0 (before corticotomy) and T1 (6 months after surgery). Several tests were used for statistical analysis of the data. Results: In the maxillary arch, the bone thickness measured after corticotomy in males was 0.64 mm at the cervical level, 0.53 mm at the medial level and 0.30 mm in the apical area. In females, the values were 0.46 mm (cervical), 0.37 mm (medial) and 0.36 mm (apical). In the lower arch, the values obtained for these three regions were 0.37 mm, 0.30 mm and 0.37 mm for males and 0.58 mm, 0.32 mm and 0.43 mm for female subjects. All values were statistically significant. The root length for the lower teeth at T0 was 11.98 ± 2.24 mm at T0 and 11.97 ± 2.24 mm at T1. For the upper teeth, the root length at T0 was 13.83 ± 2.28 mm and 13.81 ± 2.28 mm. Conclusions: Comparing the measurements, it was observed that the biggest changes in the cortical bone were at the cervical level. In the maxillary arch, the most significant modifications were registered at the canines and the level of the first premolars, and in the lower arch at the incisors level. The measured root resorption of the teeth was considered to be statistically insignificant.

Alveolar bone thickness overlying healthy maxillary and mandibular teeth: A systematic review and meta-analysis

OBJECTIVE

To systematically review and meta-analyse the Alveolar Bone Thickness (ABT) overlying healthy teeth. The secondary objective was to review the association of ABT with gender, age, and smoking.

MATERIALS AND METHODS

The PubMed, Embase, Scopus, ProQuest, Web of Science, and Cochrane Library databases were searched up to July 2020. English articles (sample size≥10) which had used CT or CBCT to measure the ABT at clearly defined reference points were included. The maximum likelihood approach meta-analysis was used to estimate the means (95% CIs).

RESULTS

A total of 68 articles were included. The meta-analysis results were as follows: In the anterior maxilla, the mean labial plate thickness ranged from 0.42-1.75mm, while it was thicker for the posterior teeth (0.78-4.31mm). The palatal plate thickness ranged from 0.97-8.13mm. In the anterior mandible, the thickness of labial and lingual plates ranged from 0.4-3.71mm and 0.38-5.44mm, respectively. The alveolar bone was thicker for the posterior teeth both at the labial (0.66-6.31mm) and lingual (2.31-7.77mm) sides. Meta-regression revealed a significant relationship between gender and ABT at several points. There was a controversy regarding the association of ABT with age. No significant difference was evidenced between smokers and non-smokers.

CONCLUSIONS

This study presents a clear image of the alveolar bone structure. Since it has pooled ABT values from various populations, outcomes could be acknowledged as global averages. Therefore, it could provide perspective for several dental procedures, including orthodontic treatments and immediate implant placement.

Non-invasive evaluation of labial gingival and alveolar crest thickness in the maxillary anterior teeth region by 15-MHz B-mode ultrasonography

Background

Knowledge of gingival thickness (GT) and alveolar crest thickness (ACT) is essential when performing surgical and non-surgical procedures in the maxillary anterior teeth region. This study aimed at evaluating the GT and ACT in the maxillary anterior teeth region using 15-MHz B-mode Ultrasonic (US).

Methods

A total of 300 teeth from 50 healthy participants, comprising 25 women and 25 men, aged between 18 and 35 years were analyzed. We measured labial periodontal tissue structures of maxillary anterior teeth, including GT and ACT, at 3 mm apical to the gingival margin (GT3) and the crestal level, respectively. The GT and ACT measurements were correlated.

Results

The mean labial GT3 of the maxillary central incisors, lateral incisors, and canines were 1.24 ± 0.03 mm, 1.21 ± 0.03 mm and 1.11 ± 0.03 mm, respectively. Canine GT3 was significantly thin than those in the central and lateral incisors (P < 0.05). With regards to labial ACT, we recorded 0.79 ± 0.03 mm, 0.76 ± 0.02 mm and 0.73 ± 0.02 mm for maxillary central incisors, lateral incisors and canines, respectively. There were no significant differences in ACT of maxillary anterior teeth (P > 0.05). GT3 of men was greater than that of women (P < 0.05). In addition, GT and ACT were positively correlated (r = 0.32, P < 0.01).

Conclusion

15-MHz B-mode US is an effective tool for measuring labial GT and ACT of anterior teeth. There are sex-associated differences in GT3 and the correlation between the GT3 and ACT of anterior teeth is moderately positive.

How Is the Created Alveolar Space Finally Restored After Maxillary Anterior Segmental Distraction Osteogenesis?

OBJECTIVE

Maxillary anterior segmental distraction osteogenesis (MASDO) for cleft and palate patients is the alternative treatment option to correct malocclusion with maxillary arch deficiency and severe crowding. After MASDO, prosthetic considerations are crucial for patients with cleft lip and palate because it is related to facial esthetics and occlusal function. The objectives of this study were to investigate the final restoration type for created alveolar space by MASDO.

METHODS

Thirteen patients with cleft lip and palate who underwent MASDO and orthodontic treatment from the years 2000 to 2010 in Yonsei University were examined. Final restorations are classified as dental implants, conventional prosthesis, and orthodontic space closure. The relationship between the distracted areas and final restoration type was investigated. The authors evaluated lateral cephalograms obtained at predistraction osteogenesis (pre-DO; T1), postdistraction osteogenesis (post-DO; T2), and debond (T3), and measured changes from T1 to T2 and from T2 to T3.

RESULTS

There was no significant difference of final restoration percentage of dental implants, conventional prosthesis, and space closure with orthodontic treatment. However, dental implants and conventional prostheses were applied more frequently in the posterior area and in the anterior area, respectively. The relapse rate was observed as 36.7% and 22.4% in the values of N-A distance and ANB angulation in T2-T3 stage.

CONCLUSION

The MASDO site should be decided, based on final restoration goal. Among the created alveolar spaces, implants were applied mainly to the posterior site and the conventional prostheses were mostly restored to the anterior site. For space closure by orthodontic approach, the area could be both anterior or posterior.

The dimension and morphology of alveolar bone at maxillary anterior teeth in periodontitis: a retrospective analysis-using CBCT

The morphology of the alveolar bone at the maxillary anterior teeth in periodontitis patients was evaluated by cone-beam computed tomography (CBCT) to investigate the distribution of alveolar defects and provide guidance for clinical practice. Ninety periodontitis patients and 30 periodontally healthy individuals were selected to determine the morphology of the alveolar bone at the maxillary anterior teeth according to the degree of bone loss, tooth type, sex and age. The differences in the dimensions between periodontitis patients and healthy individuals were compared, and the distribution of alveolar bone defects was analyzed. A classification system was established regarding the sagittal positions and angulations of the teeth. The buccal residual bone was thicker and the lingual bone was thinner in the periodontitis patients than in the periodontally healthy individuals, and there were differences between the different tooth types, sexes and age subgroups. The buccal undercut was close to the alveolar ridge, while fenestration was reduced and the apical bone height was higher in periodontitis patients than in periodontally healthy individuals. The apical bone height increased with the aggravation of bone loss and age. The proportions of different sagittal positions changed with the aggravation of bone loss. Moreover, the teeth moved more buccally regarding the positions of the maxillary anterior teeth. The morphology of the alveolar bone at the maxillary anterior teeth differed between periodontitis patients and healthy individuals, and the differences were related to the degree of bone loss, tooth type, sex and age.

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.

A Comparison between Primary and Secondary Flap Coverage in Ridge Preservation Procedures: A Pilot Randomized Controlled Clinical Trial

Aims

To assess the bone dimensional changes after extraction and alveolar ridge preservation (ARP) using primary coverage (closed flap technique, CFT) or healing by secondary intention (open flap technique, OFT).

Materials and Methods

Ten patients (split mouth design) were planned for extraction and ARP. All sites received ARP with freeze-dried bone allograft (FDBA) and nonresorbable membrane after extraction. Clinical standardized measurements were used to assess the dimensional alterations of the alveolar ridge.

Results

All patients completed the study, and a total of 20 sites were randomized to CFT or OFT group. Center height (mean difference of 8.1 mm, SD =1.9 CFT, and 7.5 mm, SD= 1.8 OFT) and buccal height (mean difference of 0.8 mm, SD =1.0 CFT, and 0.3 mm, SD= 1.1 OFT) were significantly different within the same group. However, there was no statistically significant difference between groups. In the OFT group, the keratinized tissue width was higher and the pain VAS scores at 24 hours were lower compared with the CFT (p = 0.004 and p = 0.006, respectively).

Conclusions

Leaving the flap open did not have any effects on the dimensional changes of bone height or width. However, there was a wider band of keratinized tissue and less pain with the CFT compared with the OFT. The study protocol was registered at ClinicalTrials.gov, Identifier NCT03136913.

Alveolar bone plate measurements of maxillary anterior teeth: A retrospective Cone Beam Computed Tomography study, AlMadianh, Saudi Arabia

Purpose

To study bone profile (facial bone thickness and height of alveolar bone crest) of anterior maxillary teeth in the aesthetic area among Saudi dentulous adults.

Methods

This retrospective study was conducted at Taibah University College of Dentistry and Hospital, AlMadinah; Saudi Arabia. The analysis included 490 adult patients' Cone Beam Computed Tomography (CBCT) retrieved from Kodak Carestream-R4 database. Alveolar bone thicknesses and crest bone-height for maxillary anterior teeth were measured directly on CBCT images using built-in digital caliper. Descriptive statistics and comparative analysis were performed.

Results

Of the 490 CBCTs 186 were found useable for the study purpose. The mean age of the patients was 34.65 ± 11.57and 109 (59%) were males. Statistically significant (P < 0.001) differences were found between the mean ± SD facial plate thickness of the central incisors, lateral incisors, and canines (1.12 ± 0.28 mm, 1.14 ± 0.31 mm, and 1.03 ± 0.24 mm, respectively). In addition, facial plate height increased statistically significantly positively with age for the central incisors, lateral incisors, and canines (r = 0.543, n = 186, p = 0.001; r = 0.515, n = 186, p = 0.001; r = 0.474, n = 186, p = 0.001, respectively). Genderwise, males had statistically significantly (P < 0.00) higher facial bone thickness e.g. in central incisor (males 1.20 ± 0.29 VS females 1.04 ± 0.25, p = 0.001) and increased bone height (Males 2.62 ± 0.77VS females 2.09 ± 0.66, p = 0.001) compared to females.

Conclusion

In this study, the significant differences in bone thickness and crest height between anterior maxillary teeth in the aesthetic area was highlighted. Notably, increases in facial plate crest height was linked to age and male and female differed on both facial bone thickness and bone height.

A novel classification of anterior alveolar arch forms and alveolar bone thickness: A cone-beam computed tomography study

Purpose

This study classified alveolar arch forms and evaluated differences in alveolar bone thickness among arch forms in the anterior esthetic region using cone-beam computed tomography (CBCT) images.

Materials and Methods

Axial views of 113 CBCT images were assessed at the level of 3 mm below the cementoenamel junction (CEJ) of the right and left canines. The root center points of teeth in the anterior esthetic region were used as reference points. Arch forms were classified according to their transverse dimensions and the intercanine width-to-depth ratio. The buccolingual alveolar bone thickness of each tooth was measured at 3 mm below the CEJ and at the mid-root level. Differences in the mean thicknesses among arch forms were analyzed.

Results

Anterior maxillary arches could be classified as long narrow, short medium, long medium, and long wide arches. Significant differences in buccolingual alveolar bone thickness among the arch groups were found at both levels. The long wide arches presented the greatest bone thickness, followed by the long medium arches, while the long narrow and short medium arches were the thinnest.

Conclusion

Arch forms were classified as long narrow, short medium, long medium, and long wide. The buccolingual alveolar bone thickness exhibited significant differences among the arch forms.

Assessment of Bone Dimensions in the Anterior Maxilla: A Cone Beam Computed Tomography Study

PURPOSE

To evaluate labial and palatal bone thickness at the maxillary anterior teeth as well as distance from cemento-enamel junction (CEJ) to bone crest using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Measurements were obtained for maxillary anterior teeth of 120 subject CBCT volumes including thickness of labial and palatal plates of bone (coronal, middle, and apical thirds), and distance between CEJ and alveolar bone crest mid-labially, mesially, and distally.

RESULTS

The mean value of bone thickness at coronal, middle, and apical thirds of the labial side for central incisor roots were respectively: 0.73, 0.69, 0.60 (mm), for lateral incisors: 0.70, 0.61, 0.49 (mm), and for canines: 0.74, 0.53, 040 (mm). The thickness of palatal bone was significantly larger. The mean distance between CEJ and mid-labial bone crest for all sites was 2.16 mm.

CONCLUSION

Labial bone thickness is thin in the vast majority of maxillary anterior teeth. Use of CBCT facilitates planning for immediate implant placement and is helpful in the decision-making process when further bone augmentation is needed.

Maxillary Cortical Bone Thickness in a South-Eastern Anatolian Population: A Cone-Beam Computed Tomography Study

BACKGROUND The aim of this study was to measure the distance between the maxillary premolar and molar teeth apices to the buccal cortical bone and evaluate differences in gender and age group, using cone beam computed tomography (CBCT). MATERIAL AND METHODS This retrospective study comprised of 451 premolar and molar teeth of one hundred and thirteen patients who were admitted to Dicle University, Faculty of Dentistry, Department of Dentomaxillofacial Radiology for different reasons. Data were analyzed using Student's t-tests and Tukey HSD tests. RESULTS There was significant difference in buccal bone thickness by gender (p<0.05). The thinnest point of the maxillary buccal bone was measured in women as 2.11 mm and in men as 2.02 mm in the first premolar teeth. The thickest point of maxillary buccal bone was measured in women as 9.87 mm and in men 10.71 mm palatinal root of the first molar. A comparison of buccal bone thickness between age showed a statistically significant difference at the distobuccal and palatinal roots of the first molar, at the mesiobuccal root of the second molar (p<0.05). CONCLUSIONS The measurements of maxillar buccal bone thickness using CBCT for various dental procedures especially in endodontic surgery, orthodontic mini implant treatment, dental implant procedures, and healing after tooth extraction that are important knowledge.

Facial Alveolar Bone Width at the First and Second Maxillary Premolars in Healthy Patients: A Cone Beam Computed Tomography Study

The purpose of this study was to analyze the thickness of the facial alveolar bone at the first and second maxillary premolars and determinate the percentage of premolars that reached 2 mm in width. A retrospective study was performed, analyzing cone beam computed tomography scans from the database of the Oral Surgery Unit of the University of Valencia. Patients with periodontal disease, orthodontic treatment, absence among the first maxillary molars, premolars with endodontic treatment, or prosthetic restorations were excluded. The facial alveolar bone width was measured at 1, 2, 3, and 5 mm apical to the vestibular bone peak. A total of 44 patients were included in the study, with 72 first premolars and 72 second premolars analyzed. A descriptive analysis was performed and the normal means were assessed using the Kolmogorov-Smirnov test. The average width of the facial alveolar bone at first and second maxillary premolars was respectively: 1.41 ± 0.50 and 1.72 ± 0.56 at 1 mm, 1.68 ± 0.72 and 2.23 ± 0.66 at 2 mm, 1.71 ± 0.89 and 2.43 ± 0.82 at 3 mm, 1.44 ± 1.00 and 2.31 ± 1.06 at 5 mm from the vestibular bone peak. The facial alveolar bone width at the second maxillary premolars was greater than at the first maxillary premolars at all points measured. This information should be taken in account when planning immediate implants. Further studies are needed to analyze bone resorption at maxillary premolars to better understand facial alveolar bone width influence in implant treatment.

Classification of periodontal biotypes with the use of CBCT. A cross-sectional study

OBJECTIVES

The aim of this study is to investigate the relationship between periodontal morphometric parameters and to develop a biotype classification based on the variables examined with the use of cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Forty-two periodontally healthy subjects that underwent a CBCT examination as part of a different diagnostic procedure participated in the study. Measurements were performed on sectional images and included gingival thickness and labial bone plate thickness midbuccally, crown width to crown length ratio, bone crest to the CEJ distance and bone crest to the gingival margin distance midbuccally, and at the approximal aspects of 186 maxillary anterior teeth.

RESULTS

Gingival thickness at the level of CEJ was positively correlated with labial bone plate thickness and crown form. Crown form was not correlated with labial bone plate thickness. Cluster analysis supported the existence of four periodontal biotypes, "thin," "thick," "average," and "mixed." Labial bone plate thickness was thinner than 1 mm at 70 % of the measured sites.

CONCLUSIONS

Only 50 % of the teeth belonged to thin or thick biotype. The other 50 % of the teeth belonged to the average cluster or presented mixed characteristics. Assessment of labial bone plate thickness based on periodontal biotype should be made with caution.

CLINICAL RELEVANCE

Taking into consideration the characteristics of periodontal biotypes enables the clinician to avoid complications in periodontology, prosthetic dentistry, implant dentistry in the esthetic zone, and orthodontics.

Topographic analysis of the mandibular symphysis in a normal occlusion population using cone-beam computed tomography

At present, the relationship between the morphological characteristics of the sympheseal region and occlusion has not been well documented. The aim of the present study was to investigate the following, using cone-beam computed tomography (CBCT): Interforaminal distance, the anterior loop, labial bone thickness at the tooth apex, cortical bone thickness, and the basal bone height from the apex of the tooth to the base of the mandible. Three-dimensional CBCT was performed on 20 normal occlusion subjects (9 males and 11 females; mean age=21.9±3.0 years); the mean interforaminal distance was 53.1±3.6 mm, with 85% of the participants demonstrating a mental foramen located below the second premolars on both sides. The mean anterior loop was 1.9±0.8 mm, the mean horizontal distance value was 4.5±1.3 mm, and the mean cortical bone thickness value was 2.3±0.5 mm. An increasing tendency for cortical bone thickness was seen from the central incisor to the second premolar. The mean vertical distance value was 20.3±3.1 mm. Decreasing tendency of vertical distance was seen from the central incisor to the second premolar. Furthermore, the width (mental foramina of both sides and their anterior loops), height (teeth apices and the inferior border of the mandible), depth (cortical bone thickness of the symphysis), and safety margins for vital anatomical structures (anterior loop, tooth apex, and inferior border of mandible) should be taken into account prior to symphyseal block-bone harvesting. The results of the present study suggested that a pre-operative evaluation with CBCT may be useful for diagnosis and treatment planning, and for minimizing complications during block-bone graft.

Topical combined application of dexamethasone, vitamin C, and β-sodium glycerophosphate for healing the extraction socket in rabbits

An osteogenic inducer (OI) consisting of dexamethasone, vitamin C, and β-sodium glycerophosphate has the capacity to induce bone formation in vitro. The aim of this study was to assess the efficacy of the application of this OI on extraction socket healing. The bilateral first mandibular premolars were extracted from 75 New Zealand rabbits. Gelatin sponges carrying OI were implanted into the sockets. Sockets undergoing implantation of gelatin sponges alone were also evaluated, as well as non-implantation sockets. Specimens from each group were evaluated radiographically, histologically, and histomorphometrically using haematoxylin-eosin staining. Results showed earlier new bone formation and higher bone quality and quantity in the OI group compared to the other groups, and the differences were significant at 2, 4, 8, and 12 weeks postoperative. The OI significantly reduced the absorption of alveolar bone in terms of height; however, changes in the width were not significantly different between the three groups (P>0.05). The OI was shown to have a positive effect on healing of the tooth extraction sockets, was inexpensive, and was convenient to use during the operational procedure; therefore this could represent a promising implant material for human clinical application.

Stress distribution of posts on the endodontically treated teeth with and without bone height augmentation: A three-dimensional finite element analysis

AIMS

Adequate bone support is an essential factor to avoid undue stress to the tooth. This is important when the tooth is endodontically treated and requires a post. The purpose of the present finite element (FE) analysis study was to evaluate the stress distribution of post on endodontically treated tooth with reduced alveolar bone height support and after bone augmentation. The null hypothesis was that there is no difference between the stress distribution of post on endodontically treated teeth with reduced alveolar bone height support and after alveolar bone height augmented using bone graft substitute.

MATERIALS AND METHODS

The three-dimensional model was fabricated using ANSYS Workbench version 13.0 software to represent an endodontically treated mandibular second premolar restored with a full ceramic crown restoration and was analyzed using FE analysis. A load of 300N at an angle of 60° to the vertical was applied to the triangular ridge of the buccal cusp in a buccolingual plane. The stresses on the tooth with normal alveolar bone height, reduced alveolar bone height, and after bone augmentation because of reduced bone height were calculated using von misses stresses.

RESULTS

A maximum stress value of 136.04 MPa was observed in dentin with an alveolar bone height of 4 mm from the cemento-enamel junction (CEJ). However, after 2 mm of alveolar bone augmentation, the stress value was 104.32 MPa, which was comparable to the stress value of 105.56 observed with the normal bone height of 2 mm from the CEJ.

CONCLUSION

Similar values of stresses were observed in teeth with normal and augmented bone height. Increased stresses were observed with alveolar bone loss of 4 mm from the CEJ.

Use of cone beam computed tomography in periodontology

Diagnosis of periodontal disease mainly depends on clinical signs and symptoms. However, in the case of bone destruction, radiographs are valuable diagnostic tools as an adjunct to the clinical examination. Two dimensional periapical and panoramic radiographs are routinely used for diagnosing periodontal bone levels. In two dimensional imaging, evaluation of bone craters, lamina dura and periodontal bone level is limited by projection geometry and superpositions of adjacent anatomical structures. Those limitations of 2D radiographs can be eliminated by three-dimensional imaging techniques such as computed tomography. Cone beam computed tomography (CBCT) generates 3D volumetric images and is also commonly used in dentistry. All CBCT units provide axial, coronal and sagittal multi-planar reconstructed images without magnification. Also, panoramic images without distortion and magnification can be generated with curved planar reformation. CBCT displays 3D images that are necessary for the diagnosis of intra bony defects, furcation involvements and buccal/lingual bone destructions. CBCT applications provide obvious benefits in periodontics, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination.