Level Of Alveolar Crest Research Articles

Preliminary study on measuring interdental papilla height and thickness of the maxillary anterior teeth based on cone-beam computed tomography

To investigate the features of the fill of interdental spaces by gingival papillae and the associated factors. Fifteen volunteers with healthy gingiva were involved in this study. The height and thickness on the alveolar crest level of 62 maxillary anterior papilla were measured radiographically with cone-beam computed tomography (CBCT) scans. A standardized periodontal probe with Williams markings was used for measurements of the papilla width on the alveolar crest level. When the papilla was complete fill interdentally, the mean height of papillary tissue on the alveolar crest level (equal to contact point-bone crest) was (3.67 ± 0.51) mm. The mean thickness of papilla on the alveolar crest level was (8.38 ± 0.75) mm. The papilla height had a positive correlation with papilla thickness (r = 0.433, P < 0.001). The cone-beam computed tomography can be used for clear visualization of the papilla profile and the measurements of papilla height and thickness. Thicker and wider tissue was associated with an increased likelihood of having a complete papilla fill.

Influence of presence or absence of keratinized mucosa on the alveolar bony crest level as it relates to different buccal marginal bone thicknesses. An experimental study in dogs

To investigate the influence of the presence or absence of keratinized mucosa on the alveolar bony crest level as it relates to different buccal marginal bone thicknesses. In six beagle dogs, the mandibular premolars and first molars were extracted bilaterally. In the right side of the mandible (test), flaps were elevated, and the buccal as well as part of the lingual masticatory mucosa was removed. The flap was released coronally to allow a primary wound closure. In the left side, the wounds were left unsutured with the keratinized mucosa remaining (control). After 3months of healing, a complete absence of keratinized mucosa was found at the test sites. Two recipient sites were prepared at each side of the mandible, one in the premolar and one in the molar region. A buccal bony ridge width of approximately 1 and 2mm was obtained at the premolar and molar region, respectively. Implants were installed with the shoulder flush with the buccal alveolar bony crest, and abutments were connected to allow a nonsubmerged healing. At least 2mm of keratinized mucosa was surrounding the control sites, while at the test sites, the implants were bordered by alveolar mucosa. After 3months, the animals were euthanized and ground sections obtained. A higher vertical bony crest resorption was observed at the test compared with the control sites both at the premolar and molar regions, the differences being statistically significant. The top of the peri-implant mucosa was located more coronally at the control compared with the test sites. The horizontal resorption measured 1mm below the implant shoulder was similar at the test and control sites. Only limited differences were found between premolar and molar sites, with the exclusion of the horizontal resorption that was higher at the test compared with the control sites. A higher alveolar buccal bony crest resorption and a more apical soft tissue marginal position should be expected, when implants are surrounded with thin alveolar mucosa at the time of installation, independently of the thickness of the buccal bony crest.

A Novel Combined Surgical Approach to Vertical Alveolar Ridge Augmentation with Titanium Mesh, Resorbable Membrane, and rhPDGF-BB: A Retrospective Consecutive Case Series

The purpose of this case series was to report the clinical outcomes and histologic findings of vertical ridge augmentation using a combination of titanium mesh, resorbable collagen membrane, and recombinant human platelet-derived growth factor BB (rhPDGF-BB). Nineteen patients were included, and autogenous bone and anorganic bovine bone particles were used. The bone graft was mixed with rhPDGF-BB and loaded onto the bony defect up to the level of the adjacent alveolar crest. A pre-adapted titanium mesh was placed over the grafted region and covered with a resorbable collagen membrane, leaving no areas of the grafted region exposed. Seventeen patients exhibited good soft tissue healing. Postoperative flap dehiscence occurred relatively early in the healing period in one patient, whereas the covering collagen membrane was exposed during the later phase of the healing period in another. During reentry surgery for removal of the titanium mesh, three patients with favorable soft and hard tissue healing underwent bone biopsies for histologic evaluation of the augmented tissue just below the titanium mesh. The mean vertical height of augmented bone was 8.6 ± 4.0 mm. This report demonstrates the remarkable efficacy of guided bone regeneration using a combination of titanium mesh, resorbable collagen membrane, and rhPDGF for vertical ridge augmentation, thus expanding the indications for implant therapy and allowing recovery of the three-dimensional esthetic architecture in a severely absorbed alveolar ridge.

Evaluation of hydroxyapatite (Periobone-G) as a bone graft material and calcium sulfate barrier (Capset) in treatment of interproximal vertical defects: A clinical and radiologic study.

Background:This study has been undertaken to assess treatment response of interproximal vertical defects using an alloplast (Periobone-G) and calcium sulfate (Capset) as a barrier both clinically and radiographically.Materials and Methods:Eight patients were selected with 16 sites that were divided into control and experimental sites based on split mouth study design. Plaque index, gingival index, probing depth, clinical attachment level, gingival margin position were recorded at baseline and 9 months and radiographic assessment was done at baseline and 9 months after recording clinical parameters, the sites were randomly treated either with hydroxyapatite granules Periobone-G or hydroxyapatite granules (control group) was used to fill the osseous defect and calcium sulfate (Capset) (experiment group) barrier was placed.Result:The plaque score reduction was statistically highly significant within control and experimental groups. The gingival score reduction was significant within control and experimental groups, although there were no significant difference between the 2 groups. The pocket depth reduction was significant within control and experimental group, however, the hydroxyapatite + capset group showed significant reduction as compared with hydroxyapatite alone group. The clinical attachment gain and gingival margin position was significant within control and experimental groups, although there was no significant difference between the 2 groups. The amount of defect fill was significant in both control and experimental groups but the difference between the 2 groups was not significant. The mean change in alveolar crest level between control and experimental groups was significant (P=0.02). The percentage of original defect resolved was not significant.Conclusion:The use of calcium sulfate as a barrier proved its role in the treatment of interproximal defects. The application of calcium sulfate (Capset) barrier is easy and simple. The multifaceted properties of calcium sulfate demonstrate its usefulness in periodontal practice.

Alveolar Bone Morphology in Patients with Bilateral Complete Cleft Lip and Palate in the Mixed Dentition: Cone Beam Computed Tomography Evaluation

To verify the thickness and level of alveolar bone around the teeth adjacent to the cleft by means of cone beam computed tomography (CBCT) in patients with complete bilateral cleft lip and palate prior to bone graft surgery and orthodontic intervention. The sample comprised 10 patients with complete bilateral cleft lip and palate (five boys and five girls) in the mixed dentition. The mean age was 9.5 years, and all subjects showed a G3 interarch relationship according to the Bauru index. The thickness of alveolar bone surrounding the maxillary incisors and the maxillary canines was measured in CBCT axial section using the software iCAT Xoran System. The distance between the alveolar bone crest and the cement-enamel junction (CEJ) was measured in cross sections. The tomography images showed a thin alveolar bone plate around teeth adjacent to clefts. No bone dehiscence was observed in teeth adjacent to clefts during the mixed dentition. A slight increase in the distance between the alveolar bone crest and the CEJ was observed in the mesial and lingual aspects of canines adjacent to cleft. In patients with BCLP in the mixed dentition, teeth adjacent to the alveolar cleft are covered by a thin alveolar bone plate. However, the level of alveolar bone crest around these teeth seems to be normal, and no bone dehiscence was identified at this age.

Effect of mismatching abutments on implants with wider platforms – an experimental study in dogs

To evaluate the effect of mismatching abutments on implants with a wider platform on the peri-implant hard tissue remodeling and the soft tissue dimensions. Mandibular premolars and first molars of six Labrador dogs were extracted bilaterally. After 3months of healing, one tapered implant was installed on each side of the mandibular molar region with the implant shoulder placed at the level of the buccal alveolar bony crest. On the right side of the mandible, an abutment of reduced diameter in relation to the platform of the implant was used, creating a mismatch of 0.85mm (test), whereas an abutment of the same diameter of the implant platform was affixed in the left side of the mandible (control). The flaps were sutured to allow a non-submerged healing. After 4months, the animals were sacrificed and ground sections were obtained for histometric assessment. All implants were completely osseo-integrated. Bone levels were superior at the test than at the control sites. However, statistically significant differences were found only at the buccal and proximal aspects. The soft tissue vertical dimension was higher at the control compared with the test sites. However, statistically significant differences were demonstrated only at the buccal aspects. A mismatch of 0.85mm between the implant and the abutment yielded more coronal levels of bone-to-implant contact and a reduced height of the peri-implant soft tissue (biologic width), especially at the buccal aspect, if the implant shoulder was placed flush with the level of the buccal alveolar bony crest.

Crown Lengthening Revisited

Focused Clinical Question: What are the key considerations in selecting the best approach to crown lengthening?Summary: Crown lengthening is a surgical procedure that involves manipulation of either soft tissue or both soft and hard tissue around a tooth or teeth for esthetic or restorative purposes. Esthetic crown lengthening is indicated in patients with excessive gingival display (known as a gummy smile) or gingival overgrowth, whereas restorative (or functional) crown lengthening aims to gain retention and resistance form of sound tooth structure above the alveolar crest level in cases of subgingival caries, subgingival restorative margins, or tooth fracture. Both aim to increase the amount of supragingival tooth structure for esthetic and/or restorative purposes.Conclusions: In selecting the type of procedure for esthetic or restorative (or functional) crown lengthening, the key considerations include assessment of the width of keratinized gingiva and distance of the cemento‐enamel junction or finished restoration margin to alveolar bone around the tooth/teeth involved. This article reviews and presents a decision tree in the use of both types of procedures. In addition, the subtle differences between esthetic and restorative (or functional) crown lengthening are highlighted.

Digital Radiographic Evaluation of the Level of Alveolar Bone Crest in External Hexagon Implants Submitted to 2 Types of Implant Abutments Under Immediate Loading

The aim of this study was to evaluate by means of digital radiography the behavior of the alveolar bone crest in external hexagon implants following the use of 2 different types of abutments, one for conventional cemented prosthesis and one for modified cemented prosthesis. Ten external hexagon implants (platform 4.1) were placed in 5 patients. Initial instrumentation was carried out to obtain primary stability of the temporary prostheses under immediate loading. Each patient received both abutments for conventional and modified cemented prosthesis. Standardized digital periapical radiographies were performed at times T0 (immediately after implant placement) and T1 (4 months after implant placement). A straight line was initially established from the implant platform to the distal and mesial peri-implantar marginal bone tissue (immediately in contact with the implant) and measured by digital radiography, using Sidexis version 2.3 (Sirona Dental Systems GmbH, Bensheim, Germany) software. The data were submitted to paired-samples t-test analysis. There was no significant difference between the conventional and modified cemented prosthesis. In both cases, t-test results were within the null hypothesis level. The abutment for the modified cemented prosthesis resulted in no significant radiographic difference of alveolar bone crest height, when compared with the conventional cemented prostheses.

Role of teeth adjacent to implants installed immediately into extraction sockets: an experimental study in the dog

To evaluate the influence of the presence of both adjacent teeth on the level of alveolar bony crest at sites where implants were installed into the socket immediately after tooth extraction. Six Labrador dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in the right side of the mandible, after full-thickness flap elevation. In the left side of the mandible, an endodontic treatment of the mesial root of the third and fourth premolars was performed. Full-thickness flaps were elevated, the teeth hemi-sected, and the distal roots removed. Immediately after, implants were bilaterally installed with the margin flush to the buccal bony crest. The implants were placed in the center of the alveolus at the third premolars and toward the lingual bony plate of the alveolus at the fourth premolars. After 3months of healing, the animals were euthanized. All implants were integrated in mature bone. More bone resorption was observed at the test compared to the control sites. At the buccal aspect, a resorption of 2.8±0.5 and 1.6±0.4mm at the third premolars and of 2.4±0.6 and 0.8±0.7mm at the fourth premolars were found, at the test and control sites, respectively. At the lingual aspect, the bony crest was apically located in relation to the implant shoulder 1.5 ± 0.3 and 0.5 ± 0.5 mm at the third premolars and 1.6 ± 0.6 and 0.3 ± 1.1 mm at the fourth premolars, at the test and control sites, respectively. A lower buccal bone resorption was found at the control implants placed lingually. Multiple extractions of teeth adjacent to a socket into which implants were installed immediately after, tooth extraction induced more alveolar bone recession compared to sites where the adjacent teeth were preserved. Moreover, an implant placed more lingually yielded less recession of the buccal aspect of the implant.

Plasmin Is Essential in Preventing Periodontitis in Mice

Periodontitis involves bacterial infection, inflammation of the periodontium, degradation of gum tissue, and alveolar bone resorption, which eventually leads to loss of teeth. To study the role of the broad-spectrum protease plasmin in periodontitis, we examined the oral health of plasminogen (Plg)-deficient mice. In wild-type mice, the periodontium was unaffected at all time points studied; in Plg-deficient mice, periodontitis progressed rapidly, within 20 weeks. Morphological study results of Plg-deficient mice revealed detachment of gingival tissue, resorption of the cementum layer, formation of necrotic tissue, and severe alveolar bone degradation. IHC staining showed massive infiltration of neutrophils in the periodontal tissues. Interestingly, doubly deficient mice, lacking both tissue- and urokinase-type plasminogen activators, developed periodontal disease similar to that in Plg-deficient mice; however, mice lacking only tissue- or urokinase-type plasminogen activator remained healthy. Supplementation by injection of Plg-deficient mice with human plasminogen for 10 days led to necrotic tissue absorption, inflammation subsidence, and full regeneration of gum tissues. Notably, there was also partial regrowth of degraded alveolar bone. Taken together, our results show that plasminogen is essential for the maintenance of a healthy periodontium and plays an important role in combating the spontaneous development of chronic periodontitis. Moreover, reversal to healthy status after supplementation of Plg-deficient mice with plasminogen suggests the possibility of using plasminogen for therapy of periodontal diseases.

Periodontal effects of surgically assisted rapid palatal expansion evaluated clinically and with cone-beam computerized tomography: 6-month preliminary results

Transverse maxillary deficiency is frequently observed in patients who seek orthodontic treatment. In skeletally mature patients, transverse maxillary deficiency can be treated with surgically assisted rapid palatal expansion (SARPE). Forces delivered by the expander produce areas of compression in the periodontal ligament, which could lead to alveolar bone resorption and possible changes in the attachment level. The aim of this prospective clinical study was to evaluate the periodontal effects of SARPE by means of a complete clinical evaluation and cone-beam computerized tomography (CBCT) evaluation. The sample included 14 patients (5 males, 9 females), with a mean age of 23.0 ± 1.9 years (range: 16.4 to 39.7 years). All patients were treated using a bonded Hyrax-type expander, and the mean expansion was 9.82 mm (7.5 to 12.0 mm). All patients had a 1-year retention period. CBCT scans were taken, and periodontal charts were completed at time points T0 (initial) and T1 (6 months after expansion). SARPE seemed to have little detrimental clinical effects on the periodontium. Radiographic data demonstrated statistically significant changes: a significant decrease in the buccal alveolar bone thickness on most teeth, a significant increase in the palatal alveolar bone thickness on most teeth, a decrease in the buccal alveolar crest level of all canines and posterior teeth, and a tendency toward a decrease in the interproximal alveolar crest level on the mesial aspect of both central incisors. SARPE seems to have little detrimental effects on the periodontium clinically. However, radiographic data demonstrated some statistically significant changes, which could eventually have a significant clinical impact on the periodontium.

Assessment of combination techniques in enhancing the regenerative potential of tricalcium phosphate graft in treatment of infrabony periodontal defects

The purpose of the present study was to evaluate and compare the clinical outcome of infrabony defects following reconstructive surgery with the use of tricalcium phosphate (TCP) alone; TCP and citric acid (CA) root conditioning; and TCP, CA, and oxidized regenerated cellulose (ORC) membrane. Thirty-nine systemically healthy subjects with vertical infrabony defect were initially selected based on intraoral periapical radiographs and clinical examination to record probing pocket depth (PPD) and clinical attachment level (CAL). Only 21 defects revealed two-walled configuration on surgical debridement. These defects were selected and randomly allotted to the study groups. Group 1 defects were treated with TCP, group 2 with TCP+CA, and group 3 with TCP+CA+ORC. PPD, CAL, defect depth (DD), and level of alveolar crest (AC) were evaluated at the time of initial surgery and after 6 months at surgical re-entry. These measurements were utilized to calculate PPD reduction, CAL gain, defect fill (DF), %defect fill (%DF), and crestal resorption (CR). A paired t-test was used for assessing changes in each group. Unpaired t-test was used for intergroup comparisons. All three groups showed statistically significant PPD reduction, CAL gain, DF, and %DF, but insignificant CR at the end of 6 months. On intergroup comparison, no statistically significant differences were noted between the groups for all the parameters. Efficacy of combination techniques using TCP+CA; TCP+CA+ORC in treatment of periodontal infrabony defects is at least equal to that of TCP alone.

Clinical Management of Mid‐Root Fracture in Maxillary Central Incisors: Case Reports

Management of mid-root fractures presents a formidable challenge for clinicians because of the difficulty of achieving a stable reunion of fracture fragments. This article presents two varied treatment options for mid-root fractures. A 15-year-old female reported an impact injury to the maxillary anterior teeth 2 days after its occurrence. Clinically, the maxillary left central incisor was palatally-extruded with a negative vitality response and radiographic evidence of an oblique fracture at the middle third of the root. An endodontic implant was employed which utilized an open technique and has been on follow-up for ten months. A 32-year-old male reported an injury, which resulted in a mobile maxillary right central incisor, three months after its occurrence. Through clinical and radiographic means, a discolored, extruded, and non-vital maxillary right central incisor with an oblique root fracture at the alveolar-crest level was observed. Exploratory surgery was performed; an apical barrier was created with a mineral trioxide aggregate and obturated with gutta percha. The fragments were stabilized with a fiber post and patient has been on follow-up for five months. Short-term follow-up for both of the cases showed promising results both clinically and radiographically.

Influence of implant positioning in extraction sockets on osseointegration: histomorphometric analyses in dogs

To evaluate the influence of implant positioning into extraction sockets on osseointegration. Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, the implants were positioned in the center of the alveolus, while in the test sites, the implants were positioned 0.8 mm deeper and more lingually. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. All implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test sites. After 4 months of healing, at the buccal aspects of the control and test sites, the location of the implant rough/smooth limit to the alveolar crest was 2 + or - 0.9 mm and 0.6 + or - 0.9 mm, respectively (P<0.05). At the lingual aspect, the bony crest was located 0.4 mm apically and 0.2 mm coronally to the implant rough/smooth limit at the control and test sites, respectively (NS). From a clinical point of view, implants installed into extraction sockets should be positioned approximately 1 mm deeper than the level of the buccal alveolar crest and in a lingual position in relation to the center of the alveolus in order to reduce or eliminate the exposure above the alveolar crest of the endosseous (rough) portion of the implant.

Peri-implant bone reactions around immediately loaded conical implants with different prosthetic suprastructures: histological and histomorphometrical study on minipigs

The aim of this study was to evaluate peri-implant bone reactions around immediately loaded conical implants with metal and acrylic resin prosthetic restorations. Five splinted conical implants were inserted in each hemimandible of six minipigs at the alveolar crest level. Ten implants were inserted in each minipig. All the implants were immediately loaded. The implants were divided into a group with an acrylic resin prosthetic restoration and into another group with a metal prosthetic restoration. No postoperative complications or deaths of the minipigs occurred. All minipigs were killed after 3 months. No implant was lost. A total of 60 implants were retrieved and processed to obtain thin ground sections. Histology and histomorphometry showed the presence of compact, mature bone around all the implants. Bone was in close contact with the implant surface starting from the first or second implant threads. A high quantity of mineralized bone was present around immediately loaded conical, root form implants. No differences in the peri-implant bone response were found in the groups with different prosthetic reconstructions.

Radiographic Characteristics of Furcation Involvements in Mandibular Molars as Prognostic Indicators of Healing After Nonsurgical Periodontal Therapy

The authors conducted a study to evaluate the radiographic characteristics of Class II mandibular furcation involvements as prognostic indicators of healing after nonsurgical periodontal therapy. Twenty-three patients with chronic periodontitis (Class II furcation involvements in mandibular molars, probing pocket depth [PPD] of 5 millimeters or greater and bleeding on probing [BOP]) were selected to receive nonsurgical periodontal treatment. The authors evaluated visible plaque index, BOP, position of the gingival margin, PPD, relative attachment level (RAL) and relative horizontal attachment level. On radiographs, the authors measured root trunk, bone attachment level in the furcation region, lesion height (Lh), furcation width at alveolar crest level inside furcation (Fw) and 2 mm apical to the fornix (Fw2), and the perpendicular distance from the horizontal line connecting mesial and distal radiographic alveolar crest to furcation fornix. They analyzed all data using linear multiple regression. Six months after treatment, the furcations showed a mean RAL gain of 1.08 mm (+/- 1.25 mm) and a PPD decrease of 2.74 mm (+/- 1.58 mm). The authors found a statistically significant influence between Fw and PPD (P = .0044), Fw2 and PPD (P = .0014), Lh and PPD (P = .0241), and Fw2 and RAL (P = .0037). Within the limitations of this study, the results suggest that Fw, Fw2 and Lh may influence the response of Class II mandibular furcations to nonsurgical periodontal therapy and may serve as prognostic indicators for this therapy. Thus, narrower and shorter root furcations would be expected to have better outcomes.

Crown lengthening for altered passive eruption

Purpose: Passive eruption is characterized by the apical shift of the dentogingival junction. As this occurs, the length of the clinical crown increases as the epithelial attachment migrates apically. Altered passive eruption occurs when the margin of gingiva is malpositioned incisally on the anatomic crown in adulthood and results in excessive gingiva. The purpose of this article is to evaluate esthetic results of crown lengthening procedure in altered passive eruption.s. Materials and Methods: Three patients who complained My front teeth look too short were included. Bone sounding with periodontal probe revealed that alveolar bone crest was close to CEJ. Based on the diagnostic information, a diagnosis of altered passive eruption was made. They were performed apically positioned flap procedure with osseous resection. Results: Six months later, all patients achieved favorable esthetic results and gingival margins were healthy and stable. Conclusion: When the diagnostic procedures reveal alveolar bone crest levels approximating the CEJ, apically positioned flap procedure with osseous resection is indicated. (J Korean Acad Periodontol 2008;38:247-252)

Periodontal effects of rapid maxillary expansion with tooth-tissue-borne and tooth-borne expanders: A computed tomography evaluation

The force delivered during rapid maxillary expansion (RME) produces areas of compression on the periodontal ligament of the supporting teeth. The resulting alveolar bone resorption can lead to unwanted tooth movement in the same direction. The purpose of this study was to evaluate periodontal changes by means of computed tomography after RME with tooth-tissue-borne and tooth-borne expanders. The sample comprised 8 girls, 11 to 14 years old, with Class I or II malocclusions with unilateral or bilateral posterior crossbites Four girls were treated with tooth-tissue-borne Haas-type expanders, and 4 were treated with tooth-borne Hyrax expanders. The appliances were activated up to the full 7-mm capacity of the expansion screw. Spiral CT scans were taken before expansion and after the 3-month retention period when the expander was removed. One-millimeter thick axial sections were exposed parallel to the palatal plane, comprising the dentoalveolar area and the base of the maxilla up to the inferior third of the nasal cavity. Multiplanar reconstruction was used to measure buccal and lingual bone plate thickness and buccal alveolar bone crest level by means of the computerized method. RME reduced the buccal bone plate thickness of supporting teeth 0.6 to 0.9 mm and increased the lingual bone plate thickness 0.8 to 1.3 mm. The increase in lingual bone plate thickness of the maxillary posterior teeth was greater in the tooth-borne expansion group than in the tooth-tissue-borne group. RME induced bone dehiscences on the anchorage teeth's buccal aspect (7.1 +/- 4.6 mm at the first premolars and 3.8 +/- 4.4 mm at the mesiobuccal area of the first molars), especially in subjects with thinner buccal bone plates. The tooth-borne expander produced greater reduction of first premolar buccal alveolar bone crest level than did the tooth-tissue-borne expander.

Quantitative analysis of errors in alveolar crest level caused by discrepant projection geometry in digital subtraction radiography: An in vivo study

This study compared the difference between 3 intraoral radiographic techniques on digital subtraction radiography (DSR) in vivo that are commonly used in a clinical setting. We evaluated and statistically analyzed the errors in the DSR image in 6 regions with 3 radiographic techniques: paralleling technique with a bite block attached to XCP, paralleling technique using XCP, and bisecting-angle technique. The amount of error using the bisecting-angle technique was too large for DSR, compared to that of the paralleling technique with a bite block attached to XCP. In the mandibular anterior region, the paralleling technique using XCP was not different from paralleling technique with a bite block attached to XCP. The lowest degree of error was present in the anterior region whereas the highest was present in the molar region. Bisecting-angle technique should be avoided, and paralleling technique using XCP can be used in the mandibular anterior region for DSR.

Avaliação da expansão rápida da maxila por meio da tomografia computadorizada: relato de um caso

Este trabalho descreve os efeitos dentoesqueléticos e periodontais da expansão rápida da maxila (ERM), avaliados por meio da tomografia computadorizada (TC), em uma jovem de 11,6 anos de idade com má oclusão de Classe I e mordida cruzada posterior unilateral funcional. Durante a fase ativa da ERM, o expansor dentossuportado com parafuso Hyrax foi ativado 7mm. A paciente submeteu-se ao exame de TC helicoidal, antes da expansão e após a remoção do aparelho expansor, findo o período de três meses de contenção. Realizaram-se cortes axiais, de um milímetro de espessura, paralelamente ao plano palatino, englobando as regiões dentoalveolar e basal da maxila, até o terço inferior da cavidade nasal. Utilizando-se o recurso de reconstruções multiplanares, mensuraram-se pelo método computadorizado: as dimensões transversas maxilares, a inclinação dos dentes posteriores, a espessura das tábuas ósseas vestibular e lingual, e o nível da crista óssea alveolar vestibular. A expansão rápida da maaxila ocasionou um significante aumento transverso em todas as regiões aferidas, com magnitude decrescente do arco dentário para a base óssea. Os dentes posteriores foram movimentados para vestibular, com um componente de inclinação e translação associados. Tal efeito ortodôntico ocasionou uma redução na espessura da tábua óssea vestibular, e um concomitante aumento na espessura da tábua óssea lingual. Após a expansão, observou-se o desenvolvimento de deiscências ósseas por vestibular dos dentes de ancoragem.