Mandibular Interforaminal Region Research Articles

Marginal Bone Level Measurements of Unsplinted Implants Used for Mandibular Overdentures: A Six-Month Randomized Prospective Clinical Study Comparing Early and Delayed Loading Protocols.

Background and purpose Implant-supported mandibular overdentures are a good alternative for patients having poor retention of mandibular conventional dentures. The aim of this prospective study was to evaluate and compare the results between early loading and delayed loading of mandibular overdentures on two unsplinted implants. Materials and methods A total of 14 completely edentulous male patients in the age group of 50-60 years were selected for the study. Two 3.5×13 mm implants were placed in the mandibular interforaminal region. The patients were divided into two groups: (i) the test group in which the overdenture was connected after one week of surgery, and (ii) the control group, in which the overdenture was connected three months after surgery. Marginal bone levels were evaluated at baseline (during loading), three months, and six months post loading. Unpaired 't' test was used for the comparison of intergroup measurements. Results No implants were lost. Marginal bone resorptions showed no statistically significant differences between the two groups over six months period after loading. Conclusion The results of this prospective clinical study suggested that there was no significant difference in the clinical and radiographic state of patients treated with implant-supported mandibular overdentures loaded either one week or three months after implant surgery.

Mandibular İnterforaminal Bölgede İmplant Cerrahisinde Karşılaşılabilecek Vasküler Komplikasyonlar ve Yönetimi

Mandibular interforaminal bölge, birçok ağız ,diş ve çene cerrahisi protokolünde özellikle de dental implant uygulamalarında tercih edilen bir alandır. Son yıllardaki vaka raporları, mandibular interforaminal bölgede birçok komplikasyonla karşılaşılabileceğini göstermektedir. Bunlardan en tehlikeli ve yaşamı tehdit edeni de üst solunum yolu obstrüksüyonuna kadar varabilen lingual arter yaralanmalarıdır. Tecrübeye bağlı olmaksızın karşılaşılabilecek bu komplikasyondan kaçınmak ancak mandibular interforaminal bölgenin vasküler anatomisine hakim olmak, işlem öncesi gerekli radyografik tetkik ve incelemeleri yapmış olmaktan geçmektedir. Hastayla ilgili yetersiz radyografik tetkik bulunması ya da anatomik varyasyon varlığı gibi durumlarda bu şekilde bir kanama komplikasyonuyla karşı karşıya kalındığındaysa, hekimin süreci ve komplikasyonu yönetebilecek bilgi ve donanımda olması gereklidir. Bu çalışmada mandibular interforaminal bölgesinin anatomik vasküler anatomisi, lingual foramenler ve bulunma sıklıklarıyla birlikte komplikasyondan kaçınma ve başa çıkma yöntemleriyle ilgili literatür özetlenmiştir. Böylece diş hekimlerinin bu ciddi komplikasyonla ilgili bilgilerini tazelemek amaçlanmaktadır.

Morphology and morphometric analysis of mental foramen in south Indian population – A CBCT study

It is essential to define the exact location of the mental foramen to avoid potential injury to the neurovascular bundle during surgical procedures in the mandibular interforaminal region. This radiographic study was aimed to evaluate the morphology and morphometric dimensions of mental foramen (MF) among Indian population. This study also investigated the dimorphic variations of mental foramen with respect to gender and laterality. The images of 80 subjects( 160 mandibular sites) with the age range of 20 to 60 years who had undergone cone beam computed tomographic (CBCT) were retrieved from the archives and examined for morphology and morphometry of mental foramen. Oval shaped mental foramen was one and a half times greater than round shape, which was predominant in females. Position 4 was the most common location on right and left side respectively. Type I and type III were the most common radiographic appearance of mental foramen on right and left side respectively. The mean mesiodistal, superoinferior and buccolingual dimensions of MF were 2.49 ± 0.86 mm, 2.83 ± 0.73 mm and 2.44 ± 0.72 mm respectively. The mean dimensions of the mental foramen were significantly higher among the males when compared to females. The mental foramen was positioned at an average of 11.13 ± 3.40 mm from the alveolar crest (MF-C) on the right side and was positioned at 10.79 ± 3.21 mm on the left side. The distance of the mental foramen from the alveolar crest was significantly higher among the Group I when compared to Group IV. The morphology of the mental foramen did not show any variations among the gender and age in the Indian population. The morphometric values of the mental foramen showed variability of 1-2 mm among different subjects of our population.

Assessment of Implant-Related Anatomical Landmarks in the Mandibular Interforaminal Region in an Iranian Population Using Cone-Beam Computed Tomography.

Background:This study was aimed to assess the implant-related anatomical landmarks in the mandibular interforaminal region in an Iranian population using cone-beam computed tomography (CBCT).Methods:In this retrospective cross-sectional study, 378 CBCT images of the mandible were evaluated for the presence of the incisive canal, anterior loop of the inferior alveolar nerve (IAN), mandibular canal, mental foramen, and incisive canal. The effect of age and gender of patients on the abovementioned variables was also evaluated. Data were analyzed using independent t-test, analysis of variance, and Chi-square test.Results:The anterior loop and the incisive canal were present in 36.24% and 97.62% of the cases, respectively. The mean length of the anterior loop and the incisive canal was 2.70 ± 1.20 mm and 12 ± 3.29 mm in the right, and 2.86 ± 1.24 mm and 12.21 ± 3.38 mm in the left side, respectively. The mean diameter of the mental foramen and incisive canal was 4.25 ± 1.08 mm and 1.89 ± 0.46 mm in the right, and 4.21 ± 1.02 mm and 1.94 ± 0.45 mm in the left side, respectively. The descending path was the most common path of the incisive canal. The distance from the incisive canal to the buccal plate and inferior border of the mandible was significantly shorter in females (P < 0.001).Conclusion:Considering the high variability and clinical significance of the incisive canal and anterior loop of the IAN, and their high prevalence, it is recommended to assess the presence/absence of these structures in the interforaminal region of the mandible on CBCT scans before surgical procedures in this region.

Three-dimensional radiographic assessment of the mandibular interforaminal donor site in different vertical facial growth types

PurposeTo assess volumetrically, the impact of vertical facial growth types (VFGT) on the mandibular interforaminal region as a potential bone donor site. Material and methods60 cone beam computed tomography (CBCT) scans of adult individuals were classified in three groups according to their SN-GoGn angle: hypodivergent group (hG) (N=20), normodivergent group (NG) (N=19) and hyperdivergent group (HG) (N=21). Total harvestable bone volume (TBV), cortico-cancellous bone volume (CBV-cBV), and cortical bone surface (CBS) were evaluated. ANOVA test followed by Tukey post hoc tests were used to compare the mean continuous outcomes according to their VFGT. ResultsThe whole sample showed a mean TBV of 1376.32±541.01mm3, CBV of 468.52±121.54mm3 and cBV of 908.73±474.71mm3. The mean CBS amounted to 782.58±146.80mm2.The comparison between the groups stated a significantly different mean TBV and cBV (-p-value<0.001). The mean CBS was significantly different (-p-value=0.015): the smallest for the NG, but not significantly different (-p-value<0.001): the highest for the HG, intermediate for the NG and the smallest for the hG. ConclusionHypodivergent individuals have the thickest cancellous bone suitable for an onlay bone graft, while hyperdivergent individuals have the thinnest bone ideal for a 3D grafting approach.

Evaluation of mandibular incisive canal and its relationship to adjacent anatomical landmarks using cone-beam computed tomography

Introduction: One of the most common accidental complications that occur during surgical procedures in the mandibular interforaminal region is the numbness of the chin and lower lip. This happens when vital structures such as the mental foramen, the mandibular incisive canal (MIC) and the anterior loop of the inferior alveolar nerve are not properly identified and protected. orthopantomogram has the least accuracy in identifying this structure. Hence, a better image such as computed tomography or cone-beam computed tomography (CBCT) should be used in the inter-mental foramen area. Aim: The aim is to assess the presence, position, and dimensions of MIC and its relationship to adjacent anatomical landmarks using CBCT. Materials and Methods: A total of 50 patients with 100 MICs of age 20–70 years are studied, and the collected data were subjected to statistical analysis. Results: Statistically significant result was obtained with the MIC to root tip of canine, MIC to lower cortex, MIC to buccal cortical plate, and diameter of MIC with regard to gender, which is more in males. MIC is more toward the buccal plate, and there is no statistically significant difference between the right and left sides. The diameter of MIC is larger in males compared to females and larger on left side compared to right side. Conclusion: Analyzing MIC using CBCT scans can be a useful tool in avoiding implant surgical complications in the anterior mandible.

EFFECT OF HYPERBARIC OXYGEN THERAPY ON THE OSSEOINTEGRATION AROUND IMPLANTS AFTER MANDIBULAR RECONSTRUCTION BY DESTRACTION OSTEOGENESIS

Increases in mandibular width by distraction osteogenesis have recently been shown to be an acceptable and stable treatment option for deficiencies, and also, in the oral rehabilitation, where one of the major problems is the alveolar bone loss, and adjacent soft tissues.Aim: The aim of this study is to evaluate the influence of hyperbaric oxygen therapy (HBOT), on the osseointegration of implants retained partial mandibular overdenture after reconstruction of mandibular deficiency by distraction osteogenesis. Methods: This study was conducted on eight male patients with a lack of the anterior mandibular jaw bone due to anterior marginal mandibulectomy, and partially edentulous maxillary arch (different classes), selected from the maxillofacial outpatient clinic, Faculty of Dentistry, Misr University for Science and Technology, (mean age 43 years, minimum 35 years and maximum 51 years). For all patient, distraction the insufficient alveolar ridge by using an Extraosseous Track Alveolar Distractor (KLS Martin, Germany), after consolidation period, patients received maxillary and mandibular conventional acrylic partial dentures prior to implant insertion. Then, each patient received two endoosseous implants in the mandibular interforaminal region, (following two stage surgical protocols), to retain partial mandibular overdentures. Patients were randomly divided by closed envelops, into two equal groups. Group I; Patients were received hyperbaric oxygen therapy (HBOT), on a protocol of five sequential sessions (study group), while Group II; Patients were received no hyperbaric oxygen therapy (HBOT), as a control group. Ball attachments were screwed to the implants, after four months of surgery. All patients received new mandibular removable partial overdentures were retained by two implants, and designed as Kennedy class IV partial overdentures, to fitted partial mandibular overdentures. Marginal bone height changes and bone density were assessed using cone beam computed tomography(CBCT); at time of prosthetic loading, then after six, and twelve months.Results: Decrease in marginal bone height and increase in bone density through a follow-up period (one year) were observed in both groups , however; group I; that received HBOT revealed less marginal bone resorption and more increase in bone density than group II. Conclusion: After mandibular reconstruction by distraction osteogenesis, hyperbaric oxygen therapy effective treatment, and improve osseointegration around implants retained partial ovedentures, as it associated with increased bone density and reduced marginal bone loss after one year follow up.

CBCT Evaluation of the Vital Mandibular Interforaminal Anatomical Structures.

Background:Oral implants are considered safe in the mandibular anterior region, but complications often occur if vital structures such as inferior alveolar nerve, mandibular incisive canal (MIC), anterior mental loop (AL), or mental foramen (MF) are not properly identified.Aim:The aim was to evaluate vital anatomical structures in the mandibular interforaminal region and to investigate sexual dimorphism and differences with respect to left and right side regions using cone-beam computed tomography (CBCT).Materials and Methods:Eighty CBCT scans (forty male and forty female) were analyzed for MF position and shape, presence and measurement of AL and MIC (both in mm), emergence patterns of mandibular canal, and symmetry of MF and AL. A pilot study was conducted on five patients to determine interobserver reliability among two oral and maxillofacial radiologists, considered for interpretation of CBCT images. All the scans were taken by CS 9300, CBCT machine adjusted at 80 kVp, 15 mA, voxel size 0.3 × 0.3 × 0.3, and field of view of 10 × 5 (mandible only). The acquired images were reconstructed into multiplanar views (axial, panoramic, and cross-sectional) for evaluation.Results:The mean age of the study population was 42.64 ± 16.22 years, with males noted with slightly higher age. Position 4 of MF (below the apex of the second premolar) was noted the most on the right side, whereas position 3 (between the first and second premolars) was noted on the left side, with 75% of symmetrical MF position. The oval-shaped MF was most common among both genders and sides. The prevalence of MIC was noted in 93.75% of patients with a mean length of 12.09 ± 5.95 mm. The prevalence of AL was 53.13%, with a mean length of 1.07 ± 1.42 mm. No statistically significant sexual dimorphism (P > 0.05) was found between genders or sides for all the evaluated interforaminal parameters.Conclusion:CBCT evaluation of vital anatomical structures needs to be elicited before planning an interforaminal placement of implants, and no sexual dimorphism was found regarding them.

Comparative study of bone height changes around immediately loaded porous tantalum parallel sided Trabecular &amp; Screw shaped implants retaining mandibular implant- overdentures using CBCT (RCT)

Objective: This study was conducted to evaluate the crestal bone height changes of immediately loaded Porous trabecular tantalum dental implants (PTTM ) and screw shaped titanium implants in mandibular two implant overdenture with CBCT scan. Subjects & Methods: Fourteen completely edentulous patients were rehabilitated with maxillary complete dentures & immediately loaded mandibular two implant overdentures. Patients were selected according to certain inclusion & exclusion criteria. Conventional maxillary & mandibular complete dentures were constructed for all patients. Patients were then randomly divided into two equal groups according to the implant type. Group (I-Intervention Group): TM implants & Group (II- control Group): Conventional titanium Screw implants were utilized. Implants were installed in the mandibular interforaminal region. Implants were immediately loaded with ball retained overdentures. Radiographic Evaluation of crestal bone height changes around the implants was made with CBCT scan; at the denture insertion visit, 6, 12 , & 24 months after denture insertion. Data were collected, tabulated & statistically analyzed. Results: All patients were satisfied with their implant overdentures, No implant loss were recorded during the follow-up Period. The results of this study had revealed that the crestal bone height gradually decreased throughout the study period in the two studied groups. The mean values of crestal bone loss were (0.497mm± 0.161, 0.362mm ±0.045, 0.120mm.±0.13, 0.9 mm±0.67) and (0.65mm± 0.076 , 0.338mm±0. 047, 0.75 ±0.407, 1.20 ±0.108) in group I & Group II respectively at 0-6 month, 6- 12 month, 12- 18 month and from 0-24 month intervals. On comparing the studied Groups: The crestal bone loss was greater in Group (II) than Group (I) along the whole follow-up intervals. In the 1st & 2nd follow -up intervals; (0-6month & 6-12 Months) bone loss was greater in Group (II) than Group- I with statistically insignificant difference (P-values 0.069 ns &0.400 ns respectively). However, in the 3rd interval (6-12months) & (12-18 months) and( 0-24months), bone loss was significantly higher in Group-II than Group-I; with (P=0.000*). Conclusions: Within the limitation of the current study: Trabecular Tantalum Dental Implants (PTTM) may induce less crestal bone loss than conventional screw-shaped titanium implants in immediately loaded mandibular implant overdentures.

Assessment of prevalence and position of mandibular incisive canal: A cone beam computed tomography study.

Objectives:To avoid anatomical and functional damage to mandibular interforaminal region during surgeries, it is necessary to detect the existence of mandibular incisive canal (MIC) and its proximity to adjacent structures. This study was aimed to evaluate the prevalence of MIC and its proximity to adjacent structures among Indian population.Materials and Methods:The images of 80 subjects with the age range of 20–60 years who had undergone cone beam computed tomography examination of the mandible were retrieved from the archival records. There was equal distribution of males and females.Results:The prevalence of MIC in the current study sample was found to be 43.89% with a slightly higher prevalence on left side as compared to right side, and higher prevalence among females as compared to males. Among different age groups, there was an increased incidence in the age group of >50 years. The distance of MIC from labial and lingual cortical plates and lower border of mandible were 4.338 ± 1.478 mm, 4.34 ± 1.53 mm and 9.417 ± 1.832 mm respectively.Conclusions:To conclude, the prevalence of MIC among Indian population was lower as compared to the prevalence among other populations. There were variations in prevalence in terms of age, gender and laterality, which could be used as a reference for further studies conducted on larger sample size. Mapping the incisive nerve canal will enable oral radiologists, to plan safely and negotiate the interforaminal region.

Analysis of the frequency of visualization of morphological variations in anatomical bone features in the mandibular interforaminal region through cone-beam computed tomography.

The purpose of this study was to analyze the frequency of visualization of anatomical bone features and their possible variations in the mandibular interforaminal region through cone-beam computed tomography (CBCT). This is a cross-sectional study that evaluated CBCT scans of the mandible of 141 women and 61 men, obtained by imaging archives from two private clinics of dental radiology. The study analyzed the frequency of visualization of: lingual symphyseal foramen (LSF), additional mental foramen (AdMF), absence of mental foramen (AbMF), mandibular incisive canal (MIC), and anterior loop (AL). Length measurements for MIC and AL were determined at first and following that the respective distances towards vestibular and lingual cortical walls were also individually verified. Statistical analyses included: Student's t test, Chi-square test, and ANOVA for the evaluation of the anatomical features observed through panoramic and parasagittal images' reconstructions. LSF presence was found in 97%, MIC in 75.9%, AL in 24%, AdMF in 4.7%, and AbMF in 2.5%. Chi-square tests demonstrated value results of p < 0.05 only for the presence of left AL in women when compared to men. Mean values for length measures of MIC and AL were of 10.1 and 2.12mm, respectively. Mean distance from AL towards vestibular and lingual cortical walls was of 2.53 and 4.05mm, respectively. Anatomical variability concerning the mandibular interforaminal region emphasizes the importance of performing CBCT in pre-operative assessment of the mandible for surgical procedures with oral implants.

Available bone morphology and status of neural structures in the mandibular interforaminal region: three-dimensional analysis of anatomical structures.

This study aimed to clarify the size and morphology of the mandible and to determine state of neural structures for the planning of the dental implantation using cone-beam computerized tomography (CBCT). Of the 252 patients, CBCT images of 48 selected patients were evaluated. The bone height and width were measured and the type of the mental portion of the inferior alveolar canal, the anterior loop length (ALL), the location of the incisive canal and lingual foramen were identified with cross-sectional and multiplane reformatted CBCT images. According to buccal and lingual concavities, the shape of the mandible is classified as type A, B and C. Bone widths of males were significantly higher than female (p < 0.05). The thickest part of the alveolar bone was measured in the middle triple zone (d line) and the thinnest part was measured in the area near the alveolar crest (b line). The most seen type of mandible was type B (45.8%) that mandible was concave on the buccal side. Bone heights had a tendency to increase towards to the anterior mandible, and bone height in male patients was slightly but not significantly greater than that in female patients. ALL was 4.2 ± 1.2mm and visible incisive canal length on CBCT was 9.7 ± 3.8mm. CBCT assessment of morphological features of the alveolar bone and locations of nerve canals and foramina in the anterior-premolar region of mandible represent useful practical anatomical information about the interforaminal region. This information is the guide to the dentist before implant surgery.

Analysis of crestal bone loss around single piece ball attachment implant placed bilaterally in canine region and wear of O-ring in implant supported overdenture: Three year follow-up.

Single piece implant in fixed prosthesis is widely been evaluated, however, long term evaluation of crestal bone loss and the wear of O-ring in single piece ball attachment implant supported overdenture is yet to be evaluated PURPOSE: The present article evaluates the crestal bone loss around single piece ball attachment implants placed bilaterally in the canine region and the wear of O-ring in implant supported overdenture over a period of three years. Twelve completely edentulous patients between the age group of 55-65 years were selected. Two 3.3 mm × 13 mm myriad snap fit implants were placed in the mandibular interforaminal region. All the implants were conventionally loaded at three months after surgical placement. Intra-oral periapical radiographs were made and crestal bone loss was measured at the end of one year and three years. The elasticity and wear of O-Ring was assessed after three years of usage. The crestal bone loss showed no significant difference between the first and third year after implant placement. The mean bone loss at the end of third year was 1.5 mm. Analysis of O-ring for change in the elasticity showed reduction in displacement and a significant increase in maximum displacement and elongation. The area of O-ring and yield stress did not show any changes from the standard value. Compression set damage was observed in the O-ring at the end of three years. The present study shows that the bilateral single piece implant supported overdenture has a success rate equivalent to the two piece implant supported overdenture and is a viable treatment option.

Anterior mandibular bone grafts by submental approach

Background: Some cases of totally edentulous mandibles are associated with extreme osseous resorption, which do not allow the placement of dental implants, even in the symphysis area. In these cases, bone reconstruction techniques are limited by the risk of gingival tear and graft exposure. Technical Note: The bone graft technique with a submental approach avoids an intraoral break and the risk of graft exposure or infection. The reconstruction was done with calvarian bone apposition in the mandibular interforaminal region. The graft was generally placed on the upper surface of the symphysis and occasionally on the underside. The scar was hidden in the submental fold. Discussion: We believe this surgical technique is mainly indicated for cases with extreme bone resorption. It allows the reconstruction of the mandibular symphysis, without an intraoral approach. The postoperative courses are uneventful thanks to the cranial bone harvesting technique. This approach can also be indicated for elderly patients who complain about ill-fitting dentures.

Characteristics of intrabony nerve canals in mandibular interforaminal region by using cone‐beam computed tomography and a recommendation of safe zone for implant and bone harvesting

Cone-beam computed tomography can accurately show anatomic structure of intrabony nerve canals in mandibular interforaminal region. The aim was to evaluate the characteristics of intrabony nerve canals in mandibular interforaminal region by using cone-beam computed tomography (CBCT) and determine a safe zone for implant and bone harvesting. Hemimandibles (824) CBCT images were obtained. The length of the anterior loop (AL), the length and diameter of the mandibular incisive canal (MIC) and its spatial distance in various landmarks were measured. The prevalence of the AL was 93.57%, and the MIC was 97.33%. The mean lengths of the anterior extension of the anterior loop (aAL), caudal extension of the anterior loop (cAL) and the MIC were 2.53 ± 1.27 mm, 6.04 ± 1.66 mm, 9.97 ± 5.15 mm, respectively. The MIC was closer to buccal border and inferior margin of mandible. The length of the AL and diameter of the MIC varied with gender. The safe zone recommended for implant surgery is 4 mm anterior and 8 mm inferior to the mental foramen, and 10 mm above the inferior margin of mandible. The chin bone should be harvested at least 10 mm below the tooth apices along with a limited depth of 4 mm.

Clinical and radiological investigations of mandibular overdentures supported by conventional or mini-dental implants: A 2-year prospective follow-up study

Statement of problemConventional dental implants are not applicable in the mandibular interforaminal region if bone volume is limited. Mini-dental implants offer an alternative means of supporting mandibular overdentures in a narrow residual ridge, without additional surgery. PurposeThe purpose of this nonrandomized clinical trial was to compare the ability of mini-dental implants with that of conventional dental implants in supporting mandibular overdentures during a 2-year clinical follow-up. Bone quality, bone resorption, implant stability, and oral health were assessed radiographically. Material and methodsA total of 32 participants with edentulism were included. Twenty-two participants (99 implants) received 4 to 5 mini-dental implants (diameter: 1.8-2.4 mm; length: 13-15 mm, study group), and 10 participants (35 implants) received 2 to 4 conventional dental implants (diameter: 3.3-3.7 mm; length: 11-13 mm, control group). The selection of the participants in the study or control group was based on the available bone volume in the mandible. The selection was not randomized. The density of cortical bone thickness was measured in Hounsfield units (HU) from computed tomography data, and patients were followed for 2 years. The participants were examined 3, 6, 12, and 24 months after surgery. Primary stability immediately after the insertion of dental implants (Periotest), secondary stability 6 months after implantation, modified plaque, bleeding on probing indices, and probing depth were measured and analyzed statistically (α=.05). ResultsThe mean HU value 6 months after implantation in the participants who received mini-dental implants was significantly (P=.035) higher (1250 HU) than that in the participants who received conventional dental implants (1100 HU). The probing depths around the conventional dental implants (1.6 and 1.8 mm, respectively) were significantly higher than those around the mini-dental implants (1.3 and 1.2 mm, respectively) 12 and 24 months after surgery, respectively (P<.001). The mean primary and secondary stability values for conventional dental implants were −4.0 and −4.9, respectively. The primary and secondary stability values for the mini-dental implants were −0.3 and −1.4, respectively. The Periotest values of the primary (measured immediately after implant insertion) and secondary implant stabilities (measured 6 months after implant insertion) were significantly higher for the conventional dental implants than for the mini-dental implants (P<.001). ConclusionsBased on this 2-year clinical trial, patients receiving mini-dental implants had clinical outcomes similar to those of patients receiving conventional dental implants to support overdenture prostheses.

Changes in biting forces with implant-supported overdenture in the lower jaw: A comparison between conventional and mini implants in a pilot study

The biting ability of patients improves noticeably after receiving implant-supported overdentures in comparison to conventional complete dentures. However, the change of biting with such treatment concepts has been quantitatively investigated in only a limited number of studies. The aim of the present study has been to measure the biting forces of edentulous patients with complete dentures and after receiving implant-supported overdentures.A total of 26 edentulous patients were included. Ten patients received two to four conventional implants (control group, Ø3.3–3.7mm, L11–13mm) and 16 patients received four to five mini implants (study group, Ø1.8–2.4mm, L13–15mm) inserted in the mandibular interforaminal region. All patients received a lower overdenture with ball/rubber ring attachments and a complete denture for the maxilla. The biting forces were measured using Prescale pressure sheets type low before the insertion of implants and after receiving implant-supported overdenture. The measured sheets were later scanned and analysed using FPD-8010E software.The range of biting forces before the insertion of implants was 80N–122N for the control group and 66–88N for the study group. After the insertion of implants, the range of biting forces increased to 167N–235N for the control group and to 81N–138N for the study group. However, the increase in biting forces after the insertion of implants was not significant for either group. No significant difference was obtained between the two implant systems.The biting forces improved after insertion of implants regardless of which implant system was used. However, the degree of improvement is noticeably related to the original bone quality of the mandible at the insertion regions of implants.

CONE BEAM COMPUTED TOMOGRAPHIC ASSESSMENT OF THE ANATOMICAL CHARACTERISTICS OF THE LINGUAL FORAMEN AND ITS BONY CANAL IN THE MEDIAN REGION OF THE MANDIBLE IN A GROUP OF EGYPTIAN PATIENTS

The mandibular interforaminal region has long been considered as the safest area for bone harvesting and implant placement. However, this region includes some important structures such as the lingual foramen and canal. With the increasing use of implants, the number of reported post­operative complications has been rising, therefore, preoperative assessment is a critical component of dental implant surgery to prevent the possibility of neurovascular accidents and complications. Objectives: This study was undertaken to investigate the frequency and assess the anatomical characteristics of the lingual foramina and their associated bony canals in a group of Egyptian patients using CBCT and to determine the relation of age and gender to these characteristics. Material and Methods: CBCT scans of 44 Egyptian males and 56 Egyptian females were examined to assess the frequency, distribution, diameter and vertical position of the lingual foramen as well as the course, length, angulation, bifurcation of the canal and the amount of bone buccal to it. Results: of the 100 examined cases, 44.0% showed 1 lingual foramen, 44.0% showed 2 lingual foramina, 9.0% showed 3 lingual foramina and 3.0% showed 4 lingual foramina. 93.0% were superior and 49.0% were inferior. The mean distance to the alveolar crest was 18.2 ± 4.1 mm and to the menton was 13.1 ± 3.0 mm and the mean canal length was 7.3 ± 2.4 mm. 90% of the canals ran downwards, 5.0% upwards, 5.0% horizontal and in the axial plane 16.0% of the canals ran to the right, 17.0% to the left while 67.0% ran anteriorly and only 21.0% presented bifurcations. The mean vertical angulation was 60.0 ± 20.4 degrees and the mean horizontal angulation was 4.1 ± 6.9 degrees. The mean canal diameter was 0.94 ± 0.27 mm and the mean distance buccal to the foramen was 6.3 ± 1.8 mm. There was a statistically significant negative correlation between age and superior distance and a statistically significant positive correlation between age and inferior distance while no correlation was found between gender and any characteristic. Conclusions: The lingual foramina and canals present many anatomical characteristics and variations and the CBCT images were able to demonstrate them. The clinical use of CBCT to evaluate each case individually is of utmost importance during preoperative planning to avoid post-operative complications bringing the patients’ care to a higher standard of safety and perfection.

A prospective cross-over study to evaluate the effect of two different occlusal concepts on the masseter muscle activity in implant-retained mandibular overdentures.

BackgroundThe purpose of this prospective cross-over study is to evaluate the effect of bilateral balanced occlusion and canine guidance occlusion on the masseter muscle activity using implant-retained mandibular overdentures.MethodsAfter evaluation of 12 completely edentulous patients using cone beam computed tomography (CBCT), mucoperiosteal flaps were reflected exposing the mandibular interforaminal region. Two implants were placed in the interforaminal region for each of the 12 patients. After a healing period of 3 months, acrylic maxillary complete dentures and mandibular overdentures were fabricated with bilateral balanced occlusion for 6 patients and canine guidance occlusion for the other 6 patients. Electromyographic evaluation of the masseter muscles, during clenching on a silicon index and chewing peanuts and cake, was conducted on the patients after using their dentures for 4 weeks. Each occlusion concept was then converted into the other concept using the same dentures, and the procedure of evaluation was repeated after 4 weeks. The recordings were analyzed statistically using Wilcoxon signed ranks test. p < 0.05 was considered statistically significant.ResultsThe highest electromyographic activity of the masseter muscles was recorded during clenching on a preformed silicon index followed by chewing peanut then cake for both occlusal concepts. The recordings of the masseter muscle associated with canine guidance occlusion were higher than bilateral balanced occlusion but with no statistically significant difference except between the right masseter muscles during clenching (p = 0.042*).ConclusionsBoth bilateral balanced occlusion and canine guidance occlusion can be used successfully in implant-retained mandibular overdentures without affecting masseter muscle activity.

Anatomical relationship between the sublingual fossa and the lateral lingual foramen

This study investigated the locational relationship between the sublingual fossa (SF) and the lateral lingual foramen (LLF) in order to gain useful knowledge so that perforation of the lingual cortical bone and damage to the adjacent blood vessels can be avoided when placing an endosseous implant (implant) in the mandibular interforaminal region. The deepest point of the SF (SFP) and the LLF were identified in 38 Japanese cadaver mandibles (20 edentulous and 18 dentate) by computed tomography (CT) and physical measurement. Their locations were measured. In the edentulous cases, the SFP was located approximately 15mm vertically from the alveolar crest in the direction of the mandibular lower margin in the canine and premolar regions, and the LLF was located within a 5mm radius from the SFP. Thus, significant attention to the locational relationship between the SFP and the LLF, as seen on preoperative CT, is required when placing an implant ≥3.75mm in diameter and ≥15mm in length in this region.