Matteo Giansanti

Accuracy of two stereolithographic surgical templates: A retrospective study

BACKGROUND The use of computer software and stereolithography for dental implant therapy has significantly increased during the last few years. The aim of this study was to evaluate and compare the mean accuracy and maximum deviations values of dental implant placement using two stereolithographic (SLA) guide systems. MATERIALS AND METHODS Twenty patients were selected and 227 implants were inserted using bone-, tooth- and mucosa-supported SLA surgical guides. Thirty-one guides, both single- and multiple-type, were used. Some of the single-type surgical guides were fixed with osteosynthesis screws. A postoperative computer tomography (CT) was performed and an iterative closest point algorithm was used to match the jaw of the CT preoperative with the jaw of the postoperative CT. Quantitative data of each group were described. The t-test was used to determine the influence of the utilization of the different types of SLA on accuracy values. RESULTS t-Test demonstrated a better accuracy of the multiple-type guides in almost all deviation values when the mucosa-supported guides were considered. Regarding the bone-supported template, the single-type fixed group showed a better accuracy while the highest values of deviation were registered by the multiple-type guides. The single-type group showed a better accuracy when the tooth support was considered. CONCLUSIONS The results of the present study indicated best accuracy of the single-type guide using a bone or tooth support. The multiple-type guide recorded the best accuracy data when the mucosa support was considered comparing either a fixed and a not-fixed single-type guide.

Depth deviation and occurrence of early surgical complications or unexpected events using a single stereolithographic surgi-guide §

The purpose of this study was to determine the accuracy of depth implant insertion and to describe the frequency of early surgical complications or unexpected events, recorded using a single, totally guided, stereolithographic surgi-guide (bone-, mucosa- and teeth-supported) for both osteotomy site preparation and implant delivery. Ten adults were included in this study. Six patients were treated in both arches, and the number of computer aided implantology (CAI) interventions was 16, which equalled the number of guides used, for a total of 111 implants inserted. Complications and unexpected events occurred during the positioning of the surgical guide and whilst preparing the implant site and installing implants. In order to minimize the risk of complications and unexpected events, attention must be paid to every stage of treatment, including checking computed tomography (CT) images, guide manufacturing, proper guide positioning in the mouth, guide fixation, rotational allowance of drill in tubes, shape and sharpness of the drills, first entry point, mouth opening and guided implant insertion.

Minimally invasive corticotomy in orthodontics: a new technique using a CAD/CAM surgical template

Accelerating orthodontic tooth movement is a topical issue. Despite the different techniques described in the literature, the corticotomy is the only effective and safe means of accelerating orthodontic tooth movement. Although effective, the corticotomy presents significant postoperative discomfort. The aggressive nature of these particular methods, related to the elevation of mucoperiosteal flaps and to the length of the surgery, has resulted in reluctance to proceed with this technique among both patients and the dental community. To overcome the disadvantages of the corticotomy, this technical note describes an innovative, minimally invasive, flapless procedure combining piezoelectric surgical cortical micro-incisions with the use of a 3D Printed CAD/CAM surgical guide.

Early peri-implant bone loss: a prospective cohort study

The aim of this study was to measure the early peri-implant bone level changes before the completion of an implant-abutment connection and to evaluate the influence of demographic, biologically relevant, anatomical, and implant-specific variables on these changes. A prospective cohort study design was used. STROBE guidelines were followed. The sample comprised 493 implants placed using a two-stage surgical procedure. Random allocation was used to determine the implant placement depth. Peri-apical radiographs taken at implant insertion and at the second surgery 2 months later were matched. Kappa statistics were used to compute intra- and inter-examiner reliability. The statistical analysis was performed at the implant level. Two-way analysis of variance (ANOVA) with the Bonferroni adjusted post hoc test was used to evaluate the influence of variables. One-way ANOVA with Tukeys range test and unpaired Student t-tests were used to analyze significant variables. Early marginal bone remodelling was -0.86 mm. The timing of implant placement (P=0.00) and the depth of implant placement (P≤0.05) significantly influenced early bone remodelling. Relevant radiographic early bone loss was found, but implants initially positioned below the alveolar crest and inserted ≥3 months after tooth extraction showed statistically significant higher marginal bone loss during the healing phase.

Accuracy of positioning of implants inserted using a mucosa-supported stereolithographic surgical guide in the edentulous maxilla and mandible.

PURPOSE The aim of this study was to evaluate the accuracy of implants inserted using a mucosa-supported stereolithographic surgical guide and to determine the influence of surgical management of the guide (fixed or unfixed), arch (maxilla or mandible), and smoking habit (normal or hyperplastic mucosa) on accuracy. MATERIALS AND METHODS In completely edentulous subjects, preoperative computed tomography (CT) was performed, and the images were used to plan implant positions. After the implants were placed, CT was performed again, and the presurgical and postoperative images were compared. With computer software, the jaw contours from the two CT scans were matched and the deviations between the planned and actual implant positions were evaluated. Surgical technique, arch, and smoking habit were examined as independent variables, and their influence on accuracy was evaluated with a t test. RESULTS Twenty-eight surgical guides (225 implants) were included in this study. Deviations between planned and actual positions were seen in the global coronal (mean±SD: 1.68±0.6 mm), global apical (2.19 ± 0.83 mm), and angular (4.67 ± 2.68 degrees) dimensions. Fixation of surgical guides (fixed: 4.09 degrees; not fixed: 5.62 degrees) and use of the guide in the maxilla (4.36 degrees; mandible: 5.46 degrees) resulted in statistically significantly less angular deviation (ie, better accuracy). Nonsmoking patients showed statistically significantly better accuracy in global coronal (nonsmokers: 1.54 mm; smokers: 1.83 mm) and global apical (nonsmokers: 2.08 mm; smokers: 2.27 mm) deviations. CONCLUSION The greater supporting surface of the maxilla and fixation of the surgical guide improved the accuracy of the guides. The reduced mucosa thickness in nonsmokers decreased global coronal and global apical deviation.

Is it possible to improve the accuracy of implants inserted with a stereolithographic surgical guide by reducing the tolerance between mechanical components

When using a stereolithographic surgical guide, a potentially clinically relevant error may be the mechanical error caused by the bur guide cylinder gap due to the presence of a rotational allowance of drills in the tubes. The aim of the present study was to determine if it is possible to reduce the total error by limiting the tolerance among the mechanical components and to evaluate its clinical incidence. Sixty implants were inserted in eight totally edentate subjects using the External Hex Safe(®) system with mechanical components modified to minimize the tolerance. Pre- and postoperative computed tomography images were compared, and the angular deviation was calculated between the planned and the placed implants. The mean angular deviation was 2.02° (range 0.81-3.48°; standard deviation 0.87). The results of the present study show that by limiting the error that originates from mechanical components, the total error could be significantly reduced.

Minimally invasive corticotomy in orthodontics using a three-dimensional printed CAD/CAM surgical guide.

The aim of this prospective study was to evaluate the effectiveness of an innovative, minimally invasive, flapless corticotomy procedure in orthodontics. The STROBE guidelines were followed. Ten patients with severe dental crowding and a class I molar relationship were selected to receive orthodontic treatment with clear aligners and corticotomy-facilitated orthodontics. The mean age of these patients was 21 years (range 17-28, standard deviation 6.08 years); the male to female ratio was 2:1. The main outcome was a reduction in the total treatment time to correct dental crowding. The secondary outcomes were periodontal index changes, the degree of root resorption, and patient perceptions of the method used, assessed using the short-form Oral Health Impact Profile (OHIP-14). The occurrence of early surgical complications or unexpected events was also recorded. All patients completed the treatment to correct dental crowding. The average treatment time was reduced by two-thirds. The procedure did not significantly modify the periodontal indices or oral health-related quality of life. No early surgical complications or unexpected events were observed. In short, the results indicate that this new procedure is safe and accelerates tooth movement without periodontal complications or discomfort. However, the efficacy of this procedure must be confirmed in controlled clinical trials.

Accuracy of a computer-aided implant surgical technique.

The purpose of this in vivo retrospective study was to evaluate the accuracy of a computer-designed stereolithographic surgical guide. One hundred eleven implants were placed in 10 patients. Pre- and postoperative computed tomography images were compared using specific software. Global, angular, depth, and lateral deviations were calculated between planned and placed implants. Mean global deviations between planned and placed implants at the coronal and apical aspects were 1.52 mm (range, 0.13 to 3.00 mm) and 1.97 mm (range, 0.34 to 4.23 mm), respectively, while the mean angular deviation was 4.68 degrees (range, 0.10 to 15.25 degrees). This study highlighted a reasonable mean accuracy with relatively high maximum deviations between the postoperative position and the preoperative plan. These results should serve as a warning for the clinician if implants are placed near vital structures.

The combined use of computer-guided, minimally invasive, flapless corticotomy and clear aligners as a novel approach to moderate crowding: A case report

The aim of this case report was to describe an innovative orthodontic treatment method that combined surgical and orthodontic techniques. The novel method was used to achieve a positive result in a case of moderate crowding by employing a computer-guided piezocision procedure followed by the use of clear aligners. A 23-year-old woman had a malocclusion with moderate crowding. Her periodontal indices, oral health-related quality of life (OHRQoL), and treatment time were evaluated. The treatment included interproximal corticotomy cuts extending through the entire thickness of the cortical layer, without a full-thickness flap reflection. This was achieved with a three-dimensionally printed surgical guide using computer-aided design and computer-aided manufacturing. Orthodontic force was applied to the teeth immediately after surgery by using clear appliances for better control of tooth movement. The total treatment time was 8 months. The periodontal indices improved after crowding correction, but the oral health impact profile showed a slight deterioration of OHRQoL during the 3 days following surgery. At the 2-year retention follow-up, the stability of treatment was excellent. The reduction in surgical time and patient discomfort, increased periodontal safety and patient acceptability, and accurate control of orthodontic movement without the risk of losing anchorage may encourage the use of this combined technique in appropriate cases.

Morphological and topographical characteristics of posterior supernumerary molar teeth: an epidemiological study on 25,186 subjects.

Objectives: To investigate the prevalence , gender difference , arch , morphology and position within the arch of supernumerary molar (SM) teeth in a referred Italian Caucasian population. Study Design: Records of 25,186 young patients were evaluated. Only data related to supernumerary teeth in the posterior region of the jaws were analyzed. The diagnosis of hyperdontia was formulated during the clinical and radiological examinations based on panoramic radiographs. Statistical analysis was conducted at level of subjects in the assessment of prevalence of SMs and sex ratio. Statistical analysis was conducted at level of teeth according to their morphological and topographic characteristics. The analysis of association between supernumerary morphology and arch, between supernumerary position and arch and between morphology and position was performed using the χ2 test (P≤ 0.05). Results: 61 posterior supernumerary teeth were found in 45 patients. The male to female ratio was 2.5:1 ;the mean age was 21.23 (IC:95%).The SMs were found more frequently in the maxilla (62.3%) than in the mandible; supernumerary teeth (60.7%) were more frequent than supplemental teeth. The SMs were mostly of tuberculate shape (56.8%) and paramolars teeth (64.9%) were more common than distomolars. 54% of teeth were erupted in the arch. No statistically significant relationship were found between the supernumerary teeth shape and the arch (P= 0.087) , between supernumerary teeth position and the arch (P=0.511) and between morphology and position (P=0.216). Conclusions: Epidemiological studies related to supernumerary teeth can be useful to clinicians in the early diagnosis of this anomaly. In this retrospective study the prevalence of SMs was 0.18%. SMs were more frequent in males and in the maxilla. Supernumerary were more frequent than supplemental; the conical morphology and paramolar position were the most common shape and position. Key words:Hyperdontia, prevalence, supernumerary molars, distomolar, paramolar.